JP4057434B2 - Distribution control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distribution control device used in a load distribution system, and more particularly to a distribution control device having a load distribution function for distributing traffic to a distribution destination.
[0002]
[Prior art]
In recent years, network services using Internet technology have become widespread. Internet service providers are required to stably cope with unexpected and sudden increase in users / traffic.
[0003]
In particular, when operating e-commerce / virtual stores, service stoppages such as poor response and abnormal communication (the contents of a shopping cart disappear during a shopping operation) can cause discomfort to service users and provide trust to service providers. This causes serious problems such as lowering the degree.
[0004]
Here, as a general method for the service provider to cope with the increase in users / traffic, a method of distributing the processing load by adding more content servers / network devices and scalability that can immediately expand the network The method etc. of ensuring are mentioned.
[0005]
In addition, in a distribution device that distributes packets to a content server / network device, it is an indispensable condition to distribute packets faster than the processing speed of the distribution destination (content server / network device).
[0006]
Conventionally, a server load distribution device, a firewall device, a cache device, or the like has been used as the network device that is the distribution destination. The server load distribution device is a device that distributes a server load according to an HTTP (Hyper Text Transfer Protocol) message. The firewall device is a device that detects a virus using an HTTP message such as SYN flood / Nimda. The cache device is a device that returns cache contents according to the requested content.
[0007]
Such network devices (server load distribution device, firewall device, cache device, etc.) manage traffic sessions (communication exchanges).
[0008]
Here, hereinafter, a network device that manages a traffic session is referred to as a higher layer device, and a case where a TCP (Transport Control Protocol) session / connection is handled as an example of the session will be described.
[0009]
For details of TCP, please refer to RFC793 (basic specification of TCP) and literature (eg "TCP / IP Illustrated, Volume 1: The Protocols", W. Richard Stevens).
[0010]
Conventionally, there are three types of load distribution systems for distributing packets to a plurality of higher layer devices and realizing load distribution: a star type, a copy (multicast) type, and a redirect (master / slave) type. Can be mentioned.
[0011]
FIG. 40 is a block diagram showing a configuration of the above-described conventional star-type load distribution system. In this figure, the client 10₁And client 10₂Is a computer device that is connected to the Internet 20 and transmits / receives packets to / from the server group 61 via the distribution device 30 and the higher layer device group 51.
[0012]
The distribution device 30 includes the Internet 20 and a higher layer device 50.₁~ 50_ThreeBetween the client 10 and the client 10 in accordance with a preset distribution rule.₁And 10₂Each higher layer device (higher layer device 50) corresponding to the packet (traffic) from₁~ 50_ThreeIs one of the higher layer devices).
[0013]
Here, the distribution device 30 includes “client 10” as one of the distribution rules.₁Packets from the higher layer device 50₁It is assumed that rule 1 “assign to” is set.
[0014]
Higher layer device 50₁~ 50_ThreeAre network devices that serve as packet distribution destinations in the distribution device 30, and constitute a higher layer device group 51. Also, the higher layer device 50₁~ 50_ThreeEach manages a traffic session.
[0015]
For example, the higher layer device 50₁Manages sessions 1_1,... Higher layer device 50₂Manages sessions 2_1,... Higher layer device 50_ThreeManages sessions 3_1,...
[0016]
Here, the higher layer apparatus 50₁The distribution device 30 and the server 60_{1 _ 1}~ 60_{1 _ n} It is inserted between. Higher layer device 50₂The distribution device 30 and the server 60_{2 _ 1}~ 60_{2 _ n} It is inserted between.
[0017]
Also, the higher layer device 50_ThreeThe distribution device 30 and the server 60_{Three _ 1}~ 60_{Three _ n} It is inserted between. These servers 60_{1 _ 1}~ 60_{1 _ n} , Server 60_{2 _ 1}~ 60_{2 _ n} And server 60_{Three _ 1}~ 60_{Three _ n} Constitutes a server group 61.
[0018]
Next, the operation of the conventional star-type load distribution system shown in FIG. 40 will be described. In the following, the client 10₁A case in which packets 1 to 3 are transmitted in the same session 1_1 will be described.
[0019]
First, client 10₁Packet 1 is transmitted to the distribution device 30 via the Internet 20. The distribution device 30 transmits the received packet 1 to the higher layer device 50 in accordance with the rule 1 described above.₁Sort out.
[0020]
As a result, the packet 1 is distributed in the session 1_1, and the packet 1 is assigned to the higher layer device 50.₁For example, the server 60₁_₁Received. This session 1_1 includes the higher layer device 50₁It is managed by.
[0021]
Subsequently, the client 10₁When the packet 2 corresponding to the session 1_1 is transmitted from the Internet, the packet 2 is received by the distribution device 30 via the Internet 20, and then the higher layer device 50 according to the rule 1 described above.₁Be distributed to. The packet 2 is sent to the higher layer device 50.₁For example, the server 60₁_₁Received.
[0022]
Subsequently, the client 10₁When the packet 3 corresponding to the session 1_1 is transmitted from the Internet, the packet 3 is received by the distribution device 30 via the Internet 20, and then the higher layer device 50 according to the rule 1 described above.₁Be distributed to.
[0023]
The packet 3 is sent to the higher layer device 50.₁For example, the server 60₁_₁Received. As a result, the packet communication for transmitting the packets 1 to 3 is terminated, and the session 1_1 is disconnected upon normal termination.
[0024]
Here, in the maintenance of the load distribution system shown in FIG. 40, a situation occurs in which, for example, a higher layer device is added or a higher layer device as a distribution destination is changed in order to improve the processing performance of the entire system.
[0025]
In such a situation, the configuration of the higher layer device group 51 as a distribution destination of the distribution device 30 changes. That is, with the addition or change of the higher layer device, a specific higher layer device is added to the higher layer device group 51 or the higher layer device is changed due to the configuration.
[0026]
For example, in the distribution device 30, the above-described rule 1 (“client 10₁Packets from the higher layer device 50₁”) Is rule 2 (“ client 10₁Packets from the higher layer device 50₂”)”.
[0027]
[Patent Document 1]
JP 2000-112909 A
[Patent Document 2]
JP 2002-183106 A
[0028]
[Problems to be solved by the invention]
By the way, as described above, in the conventional load distribution system (see FIG. 40), when the distribution-destination high-level layer device for the same traffic is changed due to the change of the distribution rule in the distribution device 30 at the time of maintenance, There is a problem that inconsistency occurs in the target traffic session, normal processing cannot be performed, and the session is disconnected.
[0029]
In the following, in the session 1_1 shown in FIG.₁Packet 1 transmitted from the higher layer device 50 according to the rule 1 described above in the distribution device 30.₁A case where the distribution rule is changed from rule 1 (old rule) to rule 2 (new rule) will be described.
[0030]
In this case, after changing the distribution rule, the client 10₁When the packet 2 corresponding to the session 1_1 is transmitted from the high-layer device 50 according to the rule 2, the distribution device 30₂It is distributed to.
[0031]
However, the higher layer device 50₂Then, since the information of the session 1_1 is not held, the packet 2 cannot be normally received, and the discard or the like occurs. On the other hand, the higher layer device 50₁Then, since the packet 2 following the packet 1 cannot be received, the session 1_1 is disconnected due to a timeout or the like.
[0032]
Here, as a method for avoiding the disconnection of the session, the higher layer device 50 may be used.₁~ 50_ThreeBy exchanging session information between each other, it is possible to achieve session matching so that the higher layer device that is the distribution destination in the new rule can maintain the state of the session under the old rule.
[0033]
However, this method has a serious drawback in that, when exchanging session information, the processing load of the higher layer device is increased and the network bandwidth between the higher layer devices is consumed unnecessarily.
[0034]
The present invention has been made in view of the above, and provides a distribution control device capable of preventing session disconnection when a distribution rule is changed without increasing the processing load of a traffic distribution destination and the consumption of network bandwidth. For the purpose.
[0035]
[Means for Solving the Problems]
In order to achieve the above object, the present invention receives a request for changing a distribution rule for distributing traffic to a distribution destination device group, and determines whether the traffic session is an existing session established before the rule change request. A session determining means for determining whether the session is a new session established later; and when the session determining means determines that the session is the existing session, the traffic is distributed according to a distribution rule before the rule change request. A distribution unit that distributes traffic to the destination device group, on the other hand, when it is determined that the session is the new session, according to a distribution rule after the rule change request; Features.
[0036]
According to the present invention, it is possible to prevent session disconnection for changing the distribution rule without increasing the processing load of the traffic distribution destination and the consumption of the network bandwidth.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments 1 to 6 of the distribution control device according to the present invention will be described below in detail with reference to the drawings.
[0038]
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a load distribution system to which the first exemplary embodiment of the present invention is applied. In the load balancing system shown in FIG.₁And client 100₂Is a computer device that is connected to the Internet 200 and transmits / receives packets to / from the server group 601 via the distribution device 300 and the higher layer device group 501.
[0039]
Client 100₁Is assigned an IP address <101.0.0.1>. In addition, the client 100₂Is assigned an IP address <102.0.0.1>.
[0040]
The distribution device 300 includes an Internet 200 and a higher layer device 500.₁~ 500_ThreeAnd the client 100 according to a preset distribution rule.₁And 100₂Packets (traffic) from the higher layer device 500₁~ 500_ThreeIs a device that distributes to any one of the higher layer devices.
[0041]
Specifically, the distribution device 300 is a client 100₁And 100₂Based on the distribution rule, the destination IP address of the packet (traffic) from the higher layer device 500₁~ 500_ThreeThe distribution process is executed by rewriting the IP address of any one of the higher layer devices.
[0042]
The network administrator terminal 400 is a computer terminal operated by the network administrator, and is connected to the distribution device 300. The network administrator terminal 400 transmits a maintenance request packet to the distribution device 300 when performing maintenance for changing the distribution rule in the distribution device 300, for example.
[0043]
This maintenance request packet has the format shown in FIG. 3A (sorting rule type, necessary parameters, and higher layer device list). An example of the maintenance request is as shown in FIG.
[0044]
Here, in the distribution device 300, as shown in FIG. 4, there are two device states: a maintenance state in which the maintenance is performed and a normal state in which the maintenance is not performed.
[0045]
Returning to FIG. 1, the higher layer apparatus 500₁~ 500_ThreeAre network devices that serve as packet distribution destinations in the distribution device 300, and manage the session state of the traffic. These higher layer devices 500₁~ 500_ThreeConstitutes the higher layer apparatus group 501. A representative IP address <200.0.0.10> is assigned to the higher layer apparatus group 501.
[0046]
Here, the higher layer apparatus 500₁The distribution device 300 and the server 600₁_₁~ 600₁__n It is inserted between. Higher layer device 500₂The distribution device 300 and the server 600₂_₁~ 600₂__n It is inserted between. Also, the higher layer apparatus 500_ThreeThe distribution device 300 and the server 600_Three_₁~ 600_{Three _ n} It is inserted between. These servers 600_{1 _ 1}~ 600_{1 _ n} , Server 600_{2 _ 1}~ 600_{2 _ n} And server 600_{Three _ 1}~ 600_{Three _ n} Constitutes a server group 601.
[0047]
Also, the higher layer apparatus 500₁~ 500_ThreeFrom the server group 601 to the client 100₁And 100₂The source IP address is rewritten to the representative IP address <200.0.0.10> of the higher layer apparatus group 501 and transmitted.
[0048]
Therefore, the distribution device 300 is configured so that the higher layer device 500₁~ 500_Three To client 100₁, 100₂The IP address rewriting process is not performed on the packet transmitted to the client, and the packet is simply transferred to the client side.
[0049]
Further, as another configuration, the higher layer apparatus 500₁~ 500_ThreeBut the client 100₁And 100₂The source IP address may be rewritten to the IP address <200.0.0.1-3> of each higher layer device and transmitted.
[0050]
In this case, the distribution device 300 is configured by the higher layer device 500.₁~ 500_Three To client 100₁, 100₂Has a function of rewriting the transmission source IP address to the representative IP address <200.0.0.10> of the higher layer apparatus group 501.
[0051]
In the following, communication between the higher layer apparatus group 501 and the server group 601, and the server group 601 to the client 100₁And 100₂Since the processing for the packet transmitted to is not the essence of the first embodiment, its detailed description is omitted.
[0052]
FIG. 2 is a block diagram illustrating a configuration of the sorting apparatus 300 illustrated in FIG. In the distribution apparatus 300 shown in the figure, the client-side packet receiving unit 301 includes the client 100 shown in FIG.₁And 100₂Is transmitted via the Internet 200, and the packet is converted into received packet data in a format that can be internally processed by the distribution device 300.
[0053]
The client side packet reception unit 301 receives a maintenance request packet (see FIG. 3A) from the network administrator terminal 400 (see FIG. 1), and a maintenance start signal for instructing the start of maintenance. To the maintenance / normal state switching unit 302.
[0054]
Further, when receiving the packet of the maintenance request (see FIG. 3A), the client-side packet receiving unit 301 passes the distribution rule corresponding to the distribution rule type to the new rule application unit 306 as a new rule. .
[0055]
Further, the client side packet receiving unit 301 includes the client 100.₁, 100₂When a packet is received, a packet reception process such as a header check is performed on the packet, and the received packet data is passed to each unit.
[0056]
As shown in FIG. 4, the maintenance / normal state switching unit 302 switches the apparatus state of the sorting apparatus 300 to the maintenance state or the normal state. When the maintenance / normal state switching unit 302 receives a maintenance start signal from the client-side packet reception unit 301, the maintenance / normal state switching unit 302 determines the device state of the distribution device 300 as the maintenance state, and switches the device state from the normal state to the maintenance state.
[0057]
On the other hand, when a maintenance end signal is received from a timer 309, which will be described later, the apparatus state is determined as the normal state, and the apparatus state is switched from the maintenance state to the normal state.
[0058]
Here, as shown in FIG. 4, when the distribution device 300 receives a maintenance request packet for changing the distribution rule transmitted from the network administrator terminal 400, the distribution rule (the old rule) before the change is received. ) And the changed distribution rule (new rule).
[0059]
Here, examples of the packet distribution rule include <Rule A>, <Rule B>, and <Rule C> shown in FIGS. 5A, 5B, and 5C.
[0060]
For example, when <Rule A> is applied, the client 100₁Packets from the higher layer apparatus 500 are distributed by the distribution apparatus 300._ThreeBe distributed to. In addition, the client 100₂Packets from the higher layer apparatus 500 are distributed by the distribution apparatus 300.₂Be distributed to.
[0061]
In the example shown in FIG. 4, when maintenance is started when the device state is the normal state and the rule A (normal rule) is used, the device state is changed from the normal state to the maintenance state. In this maintenance state, the rule A is set as the old rule, and the rule B as the new rule is set.
[0062]
In this maintenance state, rule A (old rule) and rule B (new rule) are used together until packet communication in session (1) (existing session) corresponding to rule A ends, and session (1) (existing session). Packets (intermediate packet, end packet) corresponding to (session) are distributed according to rule A (old rule).
[0063]
On the other hand, packets (start packet, intermediate packet) corresponding to session (2) (new session) newly established in the maintenance state are distributed according to rule B (new rule).
[0064]
Here, in the session, for example, three types of packets are transmitted: a start packet, an intermediate packet, and an end packet. The start packet has the SYN flag set to ON, and is distinguished from other midway packets and end packets (SYN flag set to OFF).
[0065]
Thus, by providing a combined period in which the new rule and the old rule are used together until all existing sessions are completed when the distribution rule is changed, it is possible to prevent the session from being disconnected when the distribution rule is changed.
[0066]
In the next normal state, rule A (old rule) is not used, rule B is changed from the new rule to a normal rule, and a packet (end packet) corresponding to session {circle around (2)} is rule B (normal rule). According to the distribution.
[0067]
In the next maintenance state, the rule B is set as the old rule, and the rule C as the new rule is set.
[0068]
In this maintenance state, rule B (old rule) and rule C (new rule) are used together until packet communication in session (3) (existing session) corresponding to rule B ends, and session (3) (existing) Packets (intermediate packet, end packet) corresponding to session) are distributed according to rule B (old rule).
[0069]
On the other hand, the packet (start packet) corresponding to the session (4) (new session) newly established in the maintenance state is distributed according to the rule C (new rule).
[0070]
Also, in the next normal state, rule B (old rule) is not used, rule C is changed from the new rule to the normal rule, and packets (intermediate packet, end packet) corresponding to session (4) are rule C ( Sorted according to normal rules).
[0071]
As described above, the distribution apparatus 300 selects a distribution rule as described below, and distributes packets.
[0072]
-Normal state: Sort according to the rule before the change of the distribution rule ("normal rule").
・ Maintenance status: Packets corresponding to sessions that have been started before maintenance (existing sessions) are distributed according to the “old rules”.
A packet corresponding to a session (new session) established in the maintenance state is distributed by the “new rule”.
[0073]
Here, in order to prevent the session from being disconnected when the distribution rule is changed, it is necessary to confirm the start and end of each session and the time (= new or existing). For this purpose, all the states of the session start / end / must be identified. If such identification processing is performed for all sessions, the processing load increases, and it is difficult to realize a high-speed distribution device.
[0074]
Therefore, the distribution apparatus 300 performs high-speed packet distribution processing in the normal state by performing session identification processing only in the maintenance state and not performing session identification in the packet distribution processing in the normal state.
[0075]
Returning to FIG. 2, the maintenance / normal state switching unit 302 notifies the distribution destination determination unit 307 and the new / existing session determination unit 303 of the current device state (normal state or maintenance state) based on the above-described determination.
[0076]
The new / existing session determination unit 303 determines whether the traffic session to be processed is a new session or an existing session. Specifically, the new / existing session determination unit 303 searches the new session identifier database 304, which will be described later, when the apparatus state is the maintenance state and the client-side packet reception unit 301 receives a packet, thereby detecting the packet. Determines whether the packet is for a new session or an existing session.
[0077]
In addition, the new / existing session determination unit 303 passes a reset signal to the timer 309 every time a packet other than the start packet is received in the maintenance state.
[0078]
As shown in FIG. 6, the new session identifier database 304 has a new session identifier consisting of “source IP address”, “source port number”, “destination IP address”, and “destination port number” for a packet. Stored. This new session identifier is included in the packet and is for identifying the new session.
[0079]
“Source IP address” is the source of the packet (client 100₁, 100₂). The “transmission source port number” is the port number of the transmission source. The “transmission destination IP address” is a representative IP address of the transmission destination (higher layer apparatus group 501). “Destination port number” is the port number of the destination.
[0080]
Further, as shown in FIG. 7, when the maintenance is started, the new session identifiers extracted from the start packet (“source IP address”, “source port number”, “destination IP address”, and “destination port number”) ]) Is added to the new session identifier database 304 as an entry.
[0081]
At the end of maintenance, the entry (new session identifier) is deleted from the new session identifier database 304.
[0082]
Returning to FIG. 2, when the received packet data is passed from the client side packet receiving unit 301, the old rule applying unit 305 determines a distribution destination according to the old rule, and assigns the obtained distribution destination identifier to the distribution destination determining unit. 307 is notified.
[0083]
When receiving the received packet data from the client-side packet receiving unit 301, the new rule applying unit 306 determines a distribution destination according to the new rule, and notifies the distribution destination determination unit 307 of the obtained distribution destination identifier.
[0084]
In addition, when the distribution rule is passed from the client side packet reception unit 301, the new rule application unit 306 applies this as a new rule. Further, the new rule application unit 306 passes the existing new rule to the old rule application unit 305 as an old rule. In this case, the old rule application unit 305 applies the old rule passed from the new rule application unit 306.
[0085]
The distribution destination determination unit 307 is received by the client side packet reception unit 301 based on the device state (normal state / maintenance state), the session type (new session / existing session), the old rule distribution destination, and the new rule distribution destination. The packet distribution destination is determined, and the distribution destination is notified to the server-side packet transmission unit 308.
[0086]
FIG. 8 is a diagram for explaining the correspondence between the packet type and the distribution rule in the first embodiment. In this figure, when the packet type is a start packet, an intermediate packet or an end packet (see FIG. 4), the device state is a maintenance state, and the session type is a new session, the new rule is applied as a distribution rule.
[0087]
Further, when the packet type is an in-progress packet or an end packet (see FIG. 4), the device state is a maintenance state, and the session type is an existing session, the old rule is applied as the distribution rule.
[0088]
Further, when the packet type is a start packet, an intermediate packet or an end packet (see FIG. 4), the device state is a normal state, and the session type is an existing session or a new session, the normal rule is applied as a distribution rule. In the first embodiment, the normal rule is stored in the new rule application unit 306 in the normal state.
[0089]
Returning to FIG. 2, the server-side packet transmission unit 308 determines that the higher layer apparatus 500 is based on the distribution destination notified from the distribution destination determination unit 307.₁~ 500_ThreeThe packet is transmitted to any one of the higher layer devices. The server-side packet transmission unit 308 determines an IP / MAC / VLAN, an output physical port, etc., and updates the header of the transmission packet.
[0090]
The timer 309 measures the packet arrival interval and determines the maintenance end time. Specifically, the timer 309 receives a reset signal from the new / existing session determination unit 303 every time a packet arrives in the maintenance state.
[0091]
Each time the timer 309 receives the reset signal, the timer 309 starts counting down from a preset time, and when a time-out occurs, the timer 309 sends a maintenance end signal to the maintenance / normal state switching unit 302 as an existing session is normally completed. hand over.
[0092]
Next, the operation of the first embodiment will be described with reference to the sequence diagram shown in FIG. 9 and the flowcharts shown in FIGS. FIG. 9 is a sequence diagram for explaining the operation of the load distribution system shown in FIG.
[0093]
Here, it is assumed that <rule A> shown in FIG. 5A is set as the packet distribution rule in the old rule application unit 305 of the distribution apparatus 300 shown in FIG. On the other hand, it is assumed that <rule B> shown in FIG. 5B is set in the new rule application unit 306 as a packet distribution rule.
[0094]
In the sorting apparatus 300, the apparatus state is assumed to be a normal state. Therefore, in this case, the normal state is notified from the maintenance / normal state switching unit 302 to the new / existing session determining unit 303 and the distribution destination determining unit 307.
[0095]
Here, in step SB1 shown in FIG. 10, the client side packet receiving unit 301 of the distribution apparatus 300 shown in FIG. 2 determines whether or not a packet has been received via the Internet 200 (see FIG. 1). In this case, the determination result is “No” and the determination is repeated.
[0096]
In step SC1 shown in FIG. 11, the maintenance / normal state switching unit 302 determines whether a maintenance start signal is passed from the client side packet reception unit 301. In this case, the determination result is “No”. To do.
[0097]
In step SC3, the maintenance / normal state switching unit 302 determines whether or not a maintenance end signal is passed from the timer 309. In this case, the determination result is “No”. Thereafter, the maintenance / normal state switching unit 302 repeats the determinations of step SC1 and step SC3 until the determination result becomes “Yes”.
[0098]
In step SD1 shown in FIG. 12, the new / existing session determination unit 303 determines whether or not the received packet data is passed from the client side packet reception unit 301. In this case, the determination result is “No”. Repeat the same judgment.
[0099]
In step SF1 shown in FIG. 14, each of the new rule applying unit 306 and the old rule applying unit 305 determines whether or not received packet data is passed from the client side packet receiving unit 301. The result is “No” and the same determination is repeated.
[0100]
In step SG1 shown in FIG. 15, the distribution destination determination unit 307 determines whether or not the packet distribution destination is notified from both the old rule application unit 305 and the new rule application unit 306. The result is “No” and the same determination is repeated.
[0101]
In step SH1 shown in FIG. 16, the server-side packet transmission unit 308 determines whether or not the received packet data has been passed from the client-side packet reception unit 301. In this case, the determination result is “No”. Repeat the same judgment.
[0102]
(Distribution processing of packet 1 in normal state)
In the normal state, in step SA1 shown in FIG.₁Transmits packet 1 in the existing session 1. In this packet 1, <source IP address> is <101.0.0.1>, <source port number> is <200>, <destination IP address> is <200.0.0.10>, and <destination port number> is It is set to <80>.
[0103]
In step SA2, the packet 1 is received by the client side packet receiving unit 301 of the distribution apparatus 300 shown in FIG. 2 via the Internet 200 shown in FIG.
[0104]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 1 corresponds to the maintenance request. In this case, the determination result is “No”.
[0105]
In step SB5, the client side packet receiving unit 301 converts the received packet 1 into received packet data, and a new / existing session determining unit 303, an old rule applying unit 305, a new rule applying unit 306, and a server side packet transmitting unit 308. After passing to step SB1, the determination of step SB1 is performed.
[0106]
When the received packet data (packet 1) is passed from the client side packet receiving unit 301, the new / existing session determining unit 303 sets the determination result of step SD1 shown in FIG. In step SD <b> 2, the new / existing session determination unit 303 checks the device state based on the notification from the maintenance / normal state switching unit 302. In this case, the apparatus state is a normal state.
[0107]
In step SD3, the new / existing session determination unit 303 determines whether or not the apparatus state is a maintenance state. In this case, the determination result is “No” and the determination in step SD1 is performed. In other words, in the normal state, the new / existing session determination unit 303 performs no processing on the received packet data (packet 1).
[0108]
When the received packet data (packet 1) is passed from the client side packet receiving unit 301, the old rule applying unit 305 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the old rule application unit 305 applies rule A (see FIG. 5A) as the currently set old rule, and determines the distribution destination of the packet 1 in the rule A.
[0109]
In this case, according to rule A (old rule), the client 100₁Since the packet 1 is received from the higher layer apparatus 500, the distribution destination of the packet 1 is_ThreeIP address <200.0.0.3>. In step SF3, the old rule application unit 305 determines that the distribution destination (higher layer apparatus 500)_ThreeIP address <200.0.0.3>) to the distribution destination determination unit 307.
[0110]
When the received packet data (packet 1) is passed from the client side packet receiving unit 301, the new rule applying unit 306 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the new rule applying unit 306 applies rule B (see FIG. 5B) as the new rule that is currently set, and determines the distribution destination of packet 1 in the rule B.
[0111]
In this case, according to the rule B (new rule), the client 100₁Since the packet 1 is received from the higher layer apparatus 500, the distribution destination of the packet 1 is₁IP address <200.0.0.1>. In step SF3, the new rule application unit 306 determines the distribution destination (higher layer apparatus 500).₁IP address <200.0.0.1>) to the distribution destination determination unit 307.
[0112]
Then, the distribution destination (higher layer device 500) is transferred from the old rule application unit 305._ThreeIP address <200.0.0.3>) and the distribution destination (higher layer device 500) from the new rule application unit 306₁) Is notified to the distribution destination determination unit 307, the distribution destination determination unit 307 sets “Yes” as a result of the determination made at step SG1 shown in FIG.
[0113]
In step SG2, the distribution destination determination unit 307 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “Yes”. And
[0114]
In step SG5, the distribution destination determination unit 307 determines the distribution destination (higher layer apparatus 500) notified from the new rule application unit 306.₁IP address <200.0.0.1>) is determined as a distribution destination of the packet 1 and notified to the server-side packet transmission unit 308, and then the determination in step SG1 is performed.
[0115]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0116]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 307. In this case, the determination result is “Yes”. On the other hand, when the distribution destination is not notified from the distribution destination determination unit 307, the server-side packet transmission unit 308 repeats the same determination with “No” as the determination result in step SH2.
[0117]
In step SH3, the server-side packet transmission unit 308 updates the header of packet 1 corresponding to the received packet data, and generates packet 1 for transmission. Specifically, the server-side packet transmission unit 308 assigns the distribution destination (higher layer device 500) notified from the new rule application unit 306.₁<Destination IP address> of packet 1 is rewritten from <200.0.0.10> to <200.0.0.1>.
[0118]
In step SH4, the server-side packet transmission unit 308 distributes the packet 1 generated in step SH3 in the existing session 1 (see FIG. 9) to the higher layer apparatus 500 that is the distribution destination.₁After transmitting to (see step SA3 in FIG. 9), the determination in step SH1 is performed.
[0119]
(Maintenance request by packet 2)
In step SA4 shown in FIG. 9, the network administrator changes the distribution rule (new rule) in the distribution device 300 from the current rule B (see FIG. 5B) to rule C (see FIG. 5C). In order to change to the above, a maintenance request is issued using the network administrator terminal 400 shown in FIG.
[0120]
Thereby, the packet 2 corresponding to the maintenance request is transmitted from the network administrator terminal 400 to the distribution device 300. In step SA5 illustrated in FIG. 9, the packet 2 is received by the client-side packet reception unit 301 of the distribution device 300.
[0121]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 2 corresponds to the maintenance request. In this case, the determination result is “Yes”.
[0122]
In step SB3, the client side packet receiving unit 301 notifies the new rule applying unit 306 of the rule C (see FIG. 5C) as the new rule. Thereby, the rule C is set as a new rule in the new rule application unit 306.
[0123]
Also, the new rule application unit 306 notifies the old rule application unit 305 of the rule B (see FIG. 5B) set before the rule C is set. As a result, the rule B is set as the old rule in the old rule application unit 305.
[0124]
In step SB4, the client side packet receiving unit 301 passes the maintenance start signal to the maintenance / normal state switching unit 302, and then performs the determination in step SB1.
[0125]
When the maintenance start signal is received, the maintenance / normal state switching unit 302 sets “Yes” as a result of the determination made at step SC1 shown in FIG. In step SC2, the maintenance / normal state switching unit 302 notifies the new / existing session determination unit 303 and the distribution destination determination unit 307 that the current device state is the maintenance state.
[0126]
In step SC3, the maintenance / normal state switching unit 302 determines whether or not a maintenance end signal is passed from the timer 309. In this case, the determination result is “No” and the determination in step SC1 is performed.
[0127]
(Distribution of packet 3 in the maintenance state)
In the maintenance state, at step SA6 shown in FIG.₁Transmits the packet 3 in the same existing session 1 as the packet 1 described above. In this packet 3, in the same manner as the packet 1 described above, <source IP address> is <101.0.0.1>, <source port number> is <200>, and <destination IP address> is <200.0.0.10. >, <Destination port number> is set to <80>.
[0128]
In step SA7, the packet 3 is received by the client side packet receiving unit 301 of the distribution apparatus 300 shown in FIG. 2 via the Internet 200 shown in FIG.
[0129]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 3 corresponds to the maintenance request. In this case, the determination result is “No”.
[0130]
In step SB5, the client side packet receiving unit 301 converts the received packet 3 into received packet data, and a new / existing session determining unit 303, an old rule applying unit 305, a new rule applying unit 306, and a server side packet transmitting unit 308. After passing to step SB1, the determination of step SB1 is performed.
[0131]
When the received packet data (packet 3) is passed from the client side packet receiving unit 301, the new / existing session determining unit 303 sets the determination result of step SD1 shown in FIG. In step SD <b> 2, the new / existing session determination unit 303 checks the device state based on the notification from the maintenance / normal state switching unit 302. In this case, the apparatus state is a maintenance state.
[0132]
In step SD3, the new / existing session determination unit 303 determines whether or not the apparatus state is a maintenance state. In this case, the determination result is “Yes”. In step SD4, the new / existing session determination unit 303 executes a maintenance state process.
[0133]
Specifically, in step SE1 shown in FIG. 13, the new / existing session determination unit 303 determines the session identifier (<source IP address> = <101.0.0.1>, <source port number> = < 200>, <destination IP address> = <200.0.0.10>, <destination port number> = <80>) as a key, the new session identifier database 304 is searched for the presence or absence of the same entry as the session identifier. To check.
[0134]
In step SE2, the new / existing session determination unit 303 determines whether there is an entry in the new session identifier database 304 that is the same as the session identifier of the packet 3, and in this case, the determination result is “No”.
[0135]
In step SE3, the new / existing session determining unit 303 checks whether or not the packet 3 is a session start packet. In step SE4, the new / existing session determination unit 303 determines whether the SYN flag of the packet 3 is on / off. In this case, assuming that the SYN flag of the packet 3 is set to OFF, the new / existing session determination unit 303 sets the determination result in step SE4 to “No”.
[0136]
In step SE7, the new / existing session determination unit 303 transmits a reset signal to the timer 309. Upon receiving the reset signal, the timer 309 starts counting down for a preset time (for example, 15 seconds).
[0137]
In step SE8, the new / existing session determination unit 303 notifies the distribution destination determination unit 307 that the session of the packet 3 is an existing session, and then performs the determination of step SD1 shown in FIG.
[0138]
When the received packet data (packet 3) is passed from the client side packet receiving unit 301, the old rule applying unit 305 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the old rule application unit 305 applies the rule B (see FIG. 5B) as the old rule that is currently set, and determines the distribution destination of the packet 3 in the rule B.
[0139]
In this case, according to rule B (old rule), the client 100₁Packet 3 is received, the distribution destination of this packet 3 is the higher layer device 500₁IP address <200.0.0.1>. In step SF3, the old rule application unit 305 determines that the distribution destination (higher layer apparatus 500)₁IP address <200.0.0.1>) to the distribution destination determination unit 307.
[0140]
When the received packet data (packet 3) is passed from the client side packet receiving unit 301, the new rule applying unit 306 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the new rule application unit 306 applies the rule C (see FIG. 5C) as the new rule that is currently set, and determines the distribution destination of the packet 3 in the rule C.
[0141]
In this case, according to rule C (new rule), the client 100₁Packet 3 is received, the distribution destination of this packet 3 is the higher layer device 500₂IP address <200.0.0.2>. In step SF3, the new rule application unit 306 determines the distribution destination (higher layer apparatus 500).₂IP address <200.0.0.2>) to the distribution destination determination unit 307.
[0142]
Then, the distribution destination (higher layer device 500) is transferred from the old rule application unit 305.₁IP address <200.0.0.1>) and the distribution destination (higher layer device 500) from the new rule application unit 306₂Are assigned to the distribution destination determination unit 307, the distribution destination determination unit 307 sets “Yes” as a result of the determination made at step SG1 shown in FIG.
[0143]
In step SG2, the distribution destination determination unit 307 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “No”. And
[0144]
In step SG3, the distribution destination determination unit 307 determines whether the session of the packet 3 is an existing session based on the notification (new session or existing session) from the new / existing session determination unit 303. In this case, The determination result is “Yes”.
[0145]
In step SG4, the distribution destination determination unit 307 determines the distribution destination (higher layer apparatus 500) notified from the old rule application unit 305.₁IP address <200.0.0.1>) is determined as the distribution destination of the packet 3 and notified to the server-side packet transmission unit 308, and then the determination in step SG1 is performed.
[0146]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0147]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 307. In this case, the determination result is “Yes”.
[0148]
In step SH3, the server-side packet transmitter 308 updates the header of the packet 3 corresponding to the received packet data, and generates a packet 3 for transmission. Specifically, the server-side packet transmission unit 308 assigns the distribution destination (higher layer device 500) notified from the new rule application unit 306.₁<Destination IP address> of packet 3 is rewritten from <200.0.0.10> to <200.0.0.1>.
[0149]
In step SH4, the server-side packet transmission unit 308 distributes the packet 3 generated in step SH3 in the existing session 1 (see FIG. 9) to the higher layer apparatus 500 that is the distribution destination.₁After transmitting to (see step SA8 in FIG. 9), the determination in step SH1 is performed.
[0150]
(Distribution of packet 4 in maintenance state)
Then, in the maintenance state, in step SA9 shown in FIG.₂Transmits a packet 4 in a new session 2 different from the existing sessions 1 of the packets 1 and 3 described above. In this packet 4, <source IP address> is <102.0.0.1>, <source port number> is <300>, <destination IP address> is <200.0.0.10>, and <destination port number> is It is set to <80>.
[0151]
In step SA10, the packet 4 is received by the client side packet receiving unit 301 of the distribution device 300 shown in FIG. 2 via the Internet 200 shown in FIG.
[0152]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 4 corresponds to the maintenance request. In this case, the determination result is “No”.
[0153]
In step SB5, the client side packet receiving unit 301 converts the received packet 4 into received packet data, and a new / existing session determining unit 303, an old rule applying unit 305, a new rule applying unit 306, and a server side packet transmitting unit 308. After passing to step SB1, the determination of step SB1 is performed.
[0154]
When the received packet data (packet 4) is passed from the client side packet receiving unit 301, the new / existing session determining unit 303 sets the determination result of step SD1 shown in FIG. In step SD <b> 2, the new / existing session determination unit 303 checks the device state based on the notification from the maintenance / normal state switching unit 302. In this case, the apparatus state is a maintenance state.
[0155]
In step SD3, the new / existing session determination unit 303 determines whether or not the apparatus state is a maintenance state. In this case, the determination result is “Yes”. In step SD4, the new / existing session determination unit 303 executes a maintenance state process.
[0156]
Specifically, in step SE1 shown in FIG. 13, the new / existing session determination unit 303 determines the session identifier (<source IP address> = <102.0.0.1>, <source port number> = < 300>, <destination IP address> = <200.0.0.10>, <destination port number> = <80>) as a key, the new session identifier database 304 is searched for the presence or absence of the same entry as the session identifier. To check.
[0157]
In step SE2, the new / existing session determination unit 303 determines whether there is an entry in the new session identifier database 304 that is identical to the session identifier of the packet 4, and in this case, the determination result is “No”.
[0158]
In step SE3, the new / existing session determination unit 303 determines whether or not the packet 4 is a session start packet from the ON / OFF state of the SYN flag of the packet 4. In this case, if the SYN flag of the packet 4 is set to ON, the new / existing session determination unit 303 sets the determination result in step SE4 to “Yes”.
[0159]
In step SE5, the new / existing session determination unit 303 adds an entry to the new session identifier database 304. Specifically, the new / existing session determination unit 303 determines the session identifier (<source IP address> = <102.0.0.1>, <source port number> = <300>, <destination IP address> of the packet 4. = <200.0.0.10>, <destination port number> = <80>) is added to the new session identifier database 304 as an entry.
[0160]
In step SE6, the new / existing session determination unit 303 notifies the distribution destination determination unit 307 that the session of the packet 4 is a new session, and then performs the determination in step SD1 shown in FIG.
[0161]
When the received packet data (packet 4) is passed from the client-side packet receiving unit 301, the old rule applying unit 305 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the old rule application unit 305 applies the rule B (see FIG. 5B) as the old rule that is currently set, and determines the distribution destination of the packet 4 in the rule B.
[0162]
In this case, according to rule B (old rule), the client 100₂Since the packet 4 is received, the distribution destination of the packet 4 is the higher layer apparatus 500.₁IP address <200.0.0.1>. In step SF3, the old rule application unit 305 determines that the distribution destination (higher layer apparatus 500)₁IP address <200.0.0.1>) to the distribution destination determination unit 307.
[0163]
Further, when the received packet data (packet 4) is passed from the client side packet receiving unit 301, the new rule applying unit 306 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the new rule application unit 306 applies rule C (see FIG. 5C) as a new rule that is currently set, and determines a distribution destination of the packet 4 in the rule C.
[0164]
In this case, according to rule C (new rule), the client 100₂Since the packet 4 is received, the distribution destination of the packet 4 is the higher layer apparatus 500.₂IP address <200.0.0.2>. In step SF3, the new rule application unit 306 determines the distribution destination (higher layer apparatus 500).₂IP address <200.0.0.2>) to the distribution destination determination unit 307.
[0165]
Then, the distribution destination (higher layer device 500) is transferred from the old rule application unit 305.₁IP address <200.0.0.1>) and the distribution destination (higher layer device 500) from the new rule application unit 306₂Are assigned to the distribution destination determination unit 307, the distribution destination determination unit 307 sets “Yes” as a result of the determination made at step SG1 shown in FIG.
[0166]
In step SG2, the distribution destination determination unit 307 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “No”. And
[0167]
In step SG3, the distribution destination determination unit 307 determines whether or not the session of the packet 4 is an existing session based on the notification (new session or existing session) from the new / existing session determination unit 303. In this case, The determination result is “No”.
[0168]
In step SG5, the distribution destination determination unit 307 determines the distribution destination (higher layer apparatus 500) notified from the new rule application unit 306.₂IP address <200.0.0.2>) is determined as a distribution destination of the packet 4 and notified to the server-side packet transmission unit 308, and then the determination in step SG1 is performed.
[0169]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0170]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 307. In this case, the determination result is “Yes”.
[0171]
In step SH3, the server-side packet transmitter 308 updates the header of the packet 4 corresponding to the received packet data, and generates a packet 4 for transmission. Specifically, the server-side packet transmission unit 308 assigns the distribution destination (higher layer device 500) notified from the new rule application unit 306.₂<Destination IP address> of packet 4 is rewritten from <200.0.0.10> to <200.0.0.2>.
[0172]
In step SH4, the server-side packet transmission unit 308 distributes the packet 4 generated in step SH3 in the new session 2 (see FIG. 9) to the higher layer apparatus 500 that is the distribution destination.₂After transmitting to (see step SA11 in FIG. 9), the determination in step SH1 is performed.
[0173]
(Distribution of packet 5 in maintenance state)
Then, in the maintenance state, in step SA12 shown in FIG.₂Transmits the packet 5 in the same new session 2 as the packet 4 described above. In this packet 5, <source IP address> is <102.0.0.1>, <source port number> is <300>, <destination IP address> is <200.0.0.10>, and <destination port number> is It is set to <80>.
[0174]
In step SA13, the packet 5 is received by the client side packet receiving unit 301 of the distribution device 300 shown in FIG. 2 via the Internet 200 shown in FIG.
[0175]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 5 corresponds to the maintenance request. In this case, the determination result is “No”.
[0176]
In step SB5, the client side packet receiving unit 301 converts the received packet 5 into received packet data, and a new / existing session determining unit 303, an old rule applying unit 305, a new rule applying unit 306, and a server side packet transmitting unit 308. After passing to step SB1, the determination of step SB1 is performed.
[0177]
When the received packet data (packet 5) is passed from the client side packet receiving unit 301, the new / existing session determining unit 303 sets the determination result of step SD1 shown in FIG. In step SD <b> 2, the new / existing session determination unit 303 checks the device state based on the notification from the maintenance / normal state switching unit 302. In this case, the apparatus state is a maintenance state.
[0178]
In step SD3, the new / existing session determination unit 303 determines whether or not the apparatus state is a maintenance state. In this case, the determination result is “Yes”. In step SD4, the new / existing session determination unit 303 executes a maintenance state process.
[0179]
Specifically, in step SE1 shown in FIG. 13, the new / existing session determination unit 303 determines the session identifier (<source IP address> = <102.0.0.1>, <source port number> = < 300>, <destination IP address> = <200.0.0.10>, <destination port number> = <80>) as a key, the new session identifier database 304 is searched for the presence or absence of the same entry as the session identifier. To check.
[0180]
In step SE2, the new / existing session determination unit 303 determines whether there is an entry in the new session identifier database 304 that is the same as the session identifier of the packet 5. In this case, the determination result is “Yes”.
[0181]
In step SE6, the new / existing session determination unit 303 notifies the distribution destination determination unit 307 that the session of the packet 5 is a new session, and then performs the determination in step SD1 shown in FIG.
[0182]
When the received packet data (packet 5) is passed from the client side packet receiving unit 301, the old rule applying unit 305 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the old rule application unit 305 applies the rule B (see FIG. 5B) as the old rule that is currently set, and determines the distribution destination of the packet 5 in the rule B.
[0183]
In this case, according to rule B (old rule), the client 100₂Since the packet 5 is received from the higher layer apparatus 500, the distribution destination of the packet 5 is₁IP address <200.0.0.1>. In step SF3, the old rule application unit 305 determines that the distribution destination (higher layer apparatus 500)₁IP address <200.0.0.1>) to the distribution destination determination unit 307.
[0184]
When the received packet data (packet 5) is passed from the client side packet receiving unit 301, the new rule applying unit 306 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the new rule application unit 306 applies rule C (see FIG. 5C) as a new rule that is currently set, and determines a distribution destination of the packet 5 in the rule C.
[0185]
In this case, according to rule C (new rule), the client 100₂Since the packet 5 is received from the higher layer apparatus 500, the distribution destination of the packet 5 is₂IP address <200.0.0.2>. In step SF3, the new rule application unit 306 determines the distribution destination (higher layer apparatus 500).₂IP address <200.0.0.2>) to the distribution destination determination unit 307.
[0186]
Then, the distribution destination (higher layer device 500) is transferred from the old rule application unit 305.₁IP address <200.0.0.1>) and the distribution destination (higher layer device 500) from the new rule application unit 306₂Are assigned to the distribution destination determination unit 307, the distribution destination determination unit 307 sets “Yes” as a result of the determination made at step SG1 shown in FIG.
[0187]
In step SG2, the distribution destination determination unit 307 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “No”. And
[0188]
In step SG3, the distribution destination determination unit 307 determines whether or not the session of the packet 5 is an existing session based on the notification (new session or existing session) from the new / existing session determination unit 303. In this case, The determination result is “No”.
[0189]
In step SG5, the distribution destination determination unit 307 determines the distribution destination (higher layer apparatus 500) notified from the new rule application unit 306.₂IP address <200.0.0.2>) is determined as a distribution destination of the packet 5 and notified to the server-side packet transmission unit 308, and then the determination of step SG1 is performed.
[0190]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0191]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 307. In this case, the determination result is “Yes”.
[0192]
In step SH3, the server-side packet transmission unit 308 updates the header of the packet 5 corresponding to the received packet data, and generates a transmission packet 5. Specifically, the server-side packet transmission unit 308 assigns the distribution destination (higher layer device 500) notified from the new rule application unit 306.₂<Destination IP address> of packet 5 is rewritten from <200.0.0.10> to <200.0.0.2>.
[0193]
In step SH4, the server-side packet transmission unit 308 distributes the packet 5 generated in step SH3 in the new session 2 (see FIG. 9) to the higher layer apparatus 500 that is the distribution destination.₂After transmitting to (see step SA14 in FIG. 9), the determination in step SH1 is performed.
[0194]
When the countdown of the timer 309 becomes 0, in step SA15 shown in FIG. 9, the timer 309 transmits a maintenance end signal to the maintenance / normal state switching unit 302 to end the maintenance.
[0195]
When the maintenance end signal is received, the maintenance / normal state switching unit 302 sets “Yes” as a result of the determination made at step SC3 shown in FIG. In step SC4, the maintenance / normal state switching unit 302 notifies the new / existing session determination unit 303 and the distribution destination determination unit 307 that the current apparatus state is the normal state.
[0196]
As a result, the new / existing session determination unit 303 deletes all entries in the new session identifier database 304 because the current apparatus state has changed from the maintenance state to the normal state.
[0197]
(Distribution of packet 6 in normal state)
In the normal state, in step SA16 shown in FIG.₂Transmits the packet 6 in the same new session 2 as the packets 4 and 5 described above. In this packet 6, <source IP address> is <102.0.0.1>, <source port number> is <300>, <destination IP address> is <200.0.0.10>, and <destination port number> is It is set to <80>.
[0198]
In step SA17, the packet 6 is received by the client side packet receiving unit 301 of the distribution device 300 shown in FIG. 2 via the Internet 200 shown in FIG.
[0199]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 6 corresponds to the maintenance request. In this case, the determination result is “No”.
[0200]
In step SB5, the client side packet receiving unit 301 converts the received packet 6 into received packet data, and a new / existing session determining unit 303, an old rule applying unit 305, a new rule applying unit 306, and a server side packet transmitting unit 308. After passing to step SB1, the determination of step SB1 is performed.
[0201]
When the received packet data (packet 6) is passed from the client side packet receiving unit 301, the new / existing session determining unit 303 sets the determination result of step SD1 shown in FIG. In step SD <b> 2, the new / existing session determination unit 303 checks the device state based on the notification from the maintenance / normal state switching unit 302. In this case, the apparatus state is a normal state.
[0202]
In step SD3, the new / existing session determination unit 303 determines whether or not the apparatus state is a maintenance state. In this case, the determination result is “No” and the determination in step SD1 is performed. In other words, in the normal state, the new / existing session determination unit 303 performs no processing on the received packet data (packet 6).
[0203]
When the received packet data (packet 6) is passed from the client side packet receiving unit 301, the old rule applying unit 305 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the old rule application unit 305 applies the rule B (see FIG. 5B) as the old rule that is currently set, and determines the distribution destination of the packet 6 in the rule B.
[0204]
In this case, according to rule B (old rule), the client 100₂Since the packet 6 is received from the higher layer apparatus 500, the distribution destination of the packet 6 is₁IP address <200.0.0.1>. In step SF3, the old rule application unit 305 determines that the distribution destination (higher layer apparatus 500)₁IP address <200.0.0.1>) to the distribution destination determination unit 307.
[0205]
When the received packet data (packet 6) is passed from the client side packet receiving unit 301, the new rule applying unit 306 sets “Yes” as a result of the determination made at step SF1 shown in FIG. In step SF2, the new rule application unit 306 applies rule C (see FIG. 5C) as a new rule that is currently set, and determines a distribution destination of the packet 6 in the rule C.
[0206]
In this case, according to rule C (new rule), the client 100₂Since the packet 6 is received from the higher layer apparatus 500, the distribution destination of the packet 6 is₂IP address <200.0.0.2>. In step SF3, the new rule application unit 306 determines the distribution destination (higher layer apparatus 500).₂IP address <200.0.0.2>) to the distribution destination determination unit 307.
[0207]
Then, the distribution destination (higher layer device 500) is transferred from the old rule application unit 305.₁IP address <200.0.0.1>) and the distribution destination (higher layer device 500) from the new rule application unit 306₂Are assigned to the distribution destination determination unit 307, the distribution destination determination unit 307 sets “Yes” as a result of the determination made at step SG1 shown in FIG.
[0208]
In step SG2, the distribution destination determination unit 307 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “Yes”. And
[0209]
In step SG5, the distribution destination determination unit 307 determines the distribution destination (higher layer apparatus 500) notified from the new rule application unit 306.₂IP address <200.0.0.2>) is determined as a distribution destination of the packet 6 and notified to the server-side packet transmission unit 308, and then the determination of step SG1 is performed.
[0210]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0211]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 307. In this case, the determination result is “Yes”.
[0212]
In step SH3, the server-side packet transmitter 308 updates the header of the packet 6 corresponding to the received packet data, and generates a transmission packet 6. Specifically, the server-side packet transmission unit 308 assigns the distribution destination (higher layer device 500) notified from the new rule application unit 306.₂<Destination IP address> of packet 6 is rewritten from <200.0.0.10> to <200.0.0.2>.
[0213]
In step SH4, the server-side packet transmission unit 308 distributes the packet 6 generated in step SH3 in the new session 2 (see FIG. 9) to the higher layer apparatus 500 that is the distribution destination.₂After sending to (see step SA18 in FIG. 9), the determination in step SH1 is performed.
[0214]
As described above, according to the first embodiment, in response to a maintenance request for changing a rule applied when traffic (packets) is distributed to the higher layer apparatus group 501, an old rule (rule before change) ) And the new rule (the rule after the change) are used together (see Fig. 4), and if it is determined that the traffic session that occurred within this combined period is an existing session, follow the old rule The traffic is distributed to the higher layer device group 501. On the other hand, if it is determined that the session is a new session, the traffic is distributed to the higher layer device group 501 according to the new rule. Do not increase the processing load of the traffic distribution destination and the consumption of network bandwidth. , It is possible to prevent the session disconnection at the time of change of the distribution rules.
[0215]
Further, according to the first embodiment, a new session identifier for identifying a new session established within the combined use period is stored in the new session identifier database 304 (see FIG. 6), and the new session identifier and traffic are stored in the new session identifier database 304 (see FIG. 6). Since the existing session or new session is determined by checking the included session identifier, the session when changing the distribution rule without increasing the processing load of the traffic distribution destination and the consumption of network bandwidth Cutting can be prevented.
[0216]
Further, according to the first embodiment, the timer 309 measures the arrival interval of traffic corresponding to the existing session, and when the arrival interval reaches the set time, the existing session is normally terminated and a maintenance end signal is sent. Since the combined period is passed to the maintenance / normal state switching unit 302, the existing session can be prevented from being disconnected by a simple method of timing the arrival interval.
[0217]
(Embodiment 2)
In the first embodiment described above, a configuration example in which the apparatus state is the normal state and the new / existing session determination unit 303 (see FIG. 2) does not perform any processing on the received packet data (packet). As described above, the above process may not be executed even when the new rule distribution destination and the old rule distribution destination are the same. Hereinafter, this configuration example will be described as a second embodiment.
[0218]
FIG. 17 is a block diagram showing a configuration of a load distribution system to which the second exemplary embodiment of the present invention is applied. In this figure, parts corresponding to those in FIG. 1 are given the same reference numerals and explanation thereof is omitted. 17, a distribution device 700 is provided instead of the distribution device 300 shown in FIG.
[0219]
FIG. 18 is a block diagram showing a configuration of the sorting apparatus 700 shown in FIG. In this figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. 18, instead of the new / existing session determination unit 303, the old rule application unit 305, the new rule application unit 306, and the distribution destination determination unit 307 shown in FIG. 2, a new / existing session determination unit 701, old rule application A section 702, a new rule application section 703, and a distribution destination determination section 704 are provided. In the distribution apparatus 700, a distribution destination comparison unit 705 is newly provided.
[0220]
In addition to the function of the new / existing session determination unit 303 (see FIG. 2), the new / existing session determination unit 701 receives the received packet when the new rule distribution destination and the old rule distribution destination are the same. Has the function of not performing any processing.
[0221]
When the client side packet receiving unit 301 receives a packet, the old rule application unit 702 determines a distribution destination based on the old rule, and assigns the distribution destination identifiers to the distribution destination determination unit 704 and the distribution destination comparison unit 705. To notify.
[0222]
When the client side packet receiving unit 301 receives a packet, the new rule applying unit 703 determines a distribution destination based on the new rule, and assigns the obtained distribution destination identifier to the distribution destination determination unit 704 and the distribution destination comparison unit 705. To notify.
[0223]
The distribution destination comparison unit 705 compares the distribution destination notified from the new rule application unit 703 with the distribution destination notified from the old rule application unit 702, and compares the comparison result (same or different) with the new / existing session determination unit. 701 and the distribution destination determination unit 704 are notified.
[0224]
Based on the comparison result from the device state (normal state / maintenance state), session state (new session / existing session), old rule distribution destination, new rule distribution destination, distribution destination comparison unit 705, the distribution destination determination unit 704 The client side packet receiving unit 301 determines a distribution destination of the received packet, and notifies the server side packet transmission unit 308 of the distribution destination.
[0225]
Next, in the same manner as in the first embodiment, the client 100 shown in FIG.₁And 100₂And higher layer device 500₁And 500₂The operation when packet communication is performed in the sequence shown in FIG. 9 will be described.
[0226]
Here, in the second embodiment, in order to simplify the description, the rule B shown in FIG. 19 is used instead of the rule B (see FIG. 5B) used in the first embodiment. In the rule B shown in the figure, the underlined portion is a change point.
[0227]
The operation of the second embodiment in FIG. 9 is substantially the same as the operation of the first embodiment, but the difference in operation between the first and second embodiments in the case of packet 4 and packet 5. Appears.
[0228]
Therefore, the distribution of the packets 4 and 5 will be described in detail below. Note that the distribution of the packet 5 is the same as that of the packet 4, and therefore the description thereof is omitted.
[0229]
(Distribution of packet 4 in maintenance state)
In the maintenance state, in step SA9 shown in FIG.₂Transmits a packet 4 in a new session 2 different from the existing sessions 1 of the packets 1 and 3 described above. In this packet 4, <source IP address> is <102.0.0.1>, <source port number> is <300>, <destination IP address> is <200.0.0.10>, and <destination port number> is It is set to <80>.
[0230]
At this time, the rule B (see FIG. 19) is set in the old rule application unit 702. In the new rule application unit 306, a rule C (see FIG. 5C) is set.
[0231]
Here, in step SI1 shown in FIG. 20, the new / existing session determination unit 701 determines whether or not the received packet data is passed from the client side packet reception unit 301. In this case, the determination result is “No”. The same judgment is repeated.
[0232]
Further, in step SJ1 shown in FIG. 21, the new rule applying unit 703 determines whether or not the received packet data is passed from the client side packet receiving unit 301. In this case, the determination result is “No” and the same. Repeat judgment.
[0233]
Further, in step SJ1 shown in FIG. 21, the old rule applying unit 702 determines whether or not the received packet data is passed from the client side packet receiving unit 301. In this case, the determination result is “No” and the same result is obtained. Repeat judgment.
[0234]
In step SK1 shown in FIG. 22, the distribution destination comparison unit 705 determines whether the distribution destination is notified from both the new rule application unit 703 and the old rule application unit 702. In this case, the determination result is displayed. The determination is repeated as “No”.
[0235]
In step SL1 shown in FIG. 23, the distribution destination determination unit 704 determines whether or not the packet distribution destination is notified from both the new rule application unit 703 and the old rule application unit 702. The result is “No” and the same determination is repeated.
[0236]
In step SA10 shown in FIG. 9, the packet 4 is received by the client side packet receiving unit 301 of the distribution apparatus 700 shown in FIG. 18 via the Internet 200 shown in FIG.
[0237]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 4 corresponds to the maintenance request. In this case, the determination result is “No”.
[0238]
In step SB5, the client side packet receiving unit 301 converts the received packet 4 into received packet data, and a new / existing session determining unit 701, an old rule applying unit 702, a new rule applying unit 703, and a server side packet transmitting unit 308. After passing to step SB1, the determination of step SB1 is performed.
[0239]
When the received packet data (packet 4) is passed from the client side packet receiving unit 301, the new / existing session determining unit 701 sets “Yes” as a result of the determination made at step SI1 shown in FIG. In step SI2, the new / existing session determination unit 701 determines whether or not the comparison result is notified from the distribution destination comparison unit 705. In this case, the determination result is “No” and the determination is repeated.
[0240]
When the received packet data (packet 4) is passed from the client side packet receiving unit 301, the old rule applying unit 702 sets “Yes” as a result of the determination made at step SJ1 shown in FIG. In step SJ2, the old rule application unit 702 applies rule B (see FIG. 19) as the old rule that is currently set, and determines a distribution destination of the packet 4 in the rule B.
[0241]
In this case, according to rule B (old rule), the client 100₂Since the packet 4 is received, the distribution destination of the packet 4 is the higher layer apparatus 500.₂IP address <200.0.0.2>. In step SJ3, the old rule application unit 702 sends the distribution destination (higher layer apparatus 500).₂Of the IP address <200.0.0.2>) to the distribution destination determination unit 704 and the distribution destination comparison unit 705.
[0242]
When the received packet data (packet 4) is passed from the client side packet receiving unit 301, the new rule applying unit 703 sets “Yes” as a result of the determination made at step SJ1 shown in FIG. In step SJ2, the new rule application unit 703 applies the rule C (see FIG. 5C) as the new rule that is currently set, and determines the distribution destination of the packet 4 in the rule C.
[0243]
In this case, according to rule C (new rule), the client 100₂Since the packet 4 is received, the distribution destination of the packet 4 is the higher layer apparatus 500.₂IP address <200.0.0.2>. In step SJ3, the new rule application unit 703 executes the distribution destination (higher layer device 500).₂Of the IP address <200.0.0.2>) to the distribution destination determination unit 704 and the distribution destination comparison unit 705.
[0244]
Then, the new rule application unit 703 distributes the distribution destination (higher layer device 500).₂IP address <200.0.0.2>) is distributed from the old rule application unit 702 (higher layer apparatus 500)₂When the IP address <200.0.0.2> is notified, the distribution destination comparing unit 705 sets “Yes” as a result of the determination made at step SK1 shown in FIG.
[0245]
In step SK2, the distribution destination comparison unit 705 distributes the distribution destination (higher layer apparatus 500) from the new rule application unit 703.₂IP address <200.0.0.2>) and the distribution destination from the old rule application unit 702 (higher layer device 500)₂IP address <200.0.0.2>).
[0246]
In step SK3, the distribution destination comparison unit 705 determines whether or not both distribution destinations are the same based on the comparison result in step SK2. In this case, the determination result is “Yes”. In step SK4, the distribution destination comparison unit 705 notifies the comparison result (same) to the new / existing session determination unit 701 and the distribution destination determination unit 704.
[0247]
If the determination result in step SK3 is “No”, in step SK5, the distribution destination comparison unit 705 notifies the new / existing session determination unit 701 and the distribution destination determination unit 704 of the comparison result (separate).
[0248]
As a result, the new / existing session determination unit 701 sets “Yes” as the determination result of step SI2 shown in FIG. In step SI3, the new / existing session determination unit 701 determines whether or not both allocation destinations are the same based on the notified comparison result (same in this case). In this case, the determination result is “Yes”. In step SI1, the determination is made.
[0249]
As described above, when the apparatus state is the maintenance state and the distribution destinations are the same, the new / existing session determination unit 701 receives the received packet data (packet 4) in the same manner as in the normal state described in the first embodiment. ) Is not executed.
[0250]
If the determination result in step SI3 is “No”, steps SI4 to SI6 are executed in the same manner as in steps SD2 to SD4 (see FIG. 12).
[0251]
The distribution destination from the old rule application unit 702 (higher layer device 500)₂IP address <200.0.0.2>) and the distribution destination from the new rule application unit 703 (higher layer device 500)₂, IP address <200.0.0.2>) is notified to the distribution destination determination unit 704, the distribution destination determination unit 704 sets “Yes” as a result of the determination made at step SL1 shown in FIG.
[0252]
In step SL2, the distribution destination determination unit 704 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “No”. And
[0253]
In step SL3, the distribution destination determination unit 704 determines whether or not both distribution destinations are the same based on the comparison result notified from the distribution destination comparison unit 705. In this case, the determination result is “Yes”. To do.
[0254]
In step SL6, the distribution destination determination unit 704 distributes the distribution destination (higher layer apparatus 500) notified from the new rule application unit 703.₂IP address <200.0.0.2>) is determined as a distribution destination of the packet 4 and notified to the server-side packet transmission unit 308, and then the determination in step SL1 is performed.
[0255]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0256]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 704. In this case, the determination result is “Yes”.
[0257]
In step SH3, the server-side packet transmitter 308 updates the header of the packet 4 corresponding to the received packet data, and generates a packet 4 for transmission. Specifically, the server-side packet transmission unit 308 assigns the distribution destination (higher layer device 500) notified from the new rule application unit 703.₂<Destination IP address> of packet 4 is rewritten from <200.0.0.10> to <200.0.0.2>.
[0258]
In step SH4, the server-side packet transmission unit 308 distributes the packet 4 generated in step SH3 in the new session 2 (see FIG. 9) to the higher layer apparatus 500 that is the distribution destination.₂After transmitting to (see step SA11 in FIG. 9), the determination in step SH1 is performed.
[0259]
On the other hand, when the determination result in step SL3 shown in FIG. 23 is “No”, in step SL4, the distribution destination determination unit 704 is based on the notification (new session or existing session) from the new / existing session determination unit 701. Then, it is determined whether or not the session of the packet 4 is an existing session. If the determination result is “No”, the process of step SL6 is executed.
[0260]
On the other hand, if the determination result in step SL4 is “Yes”, in step SL5, the distribution destination determination unit 704 determines the distribution destination notified from the old rule application unit 702 as the distribution destination of the packet 4, and the server side packet After notifying the transmitting unit 308, the determination in step SL1 is performed.
[0261]
As described above, according to the second embodiment, for the traffic generated within the combined period, the comparison result from the distribution destination comparison unit 705 shows that the distribution destination to which the old rule is applied and the distribution to which the new rule is applied. When the destination is the same, the new / existing session determination unit 701 does not make a determination, and when both the destinations are the same, the traffic is transferred to the higher layer apparatus group 501 based on the destination to which the new rule is applied. Since the distribution is performed, the distribution process can be speeded up by the amount that the above determination is not performed.
[0262]
(Embodiment 3)
In the first embodiment described above, the configuration example in which the distribution rule (distribution destination fixed rule) in which the packet distribution destination is fixed has been described. For example, in the rule B shown in FIG.₁When the start packet, the midway packet, and the end packet corresponding to the same session are sequentially received by the distribution device 300 (see FIG. 1), all of the start packet, the midway packet, and the end packet are included in the higher layer device 500.₁Be distributed to.
[0263]
Here, as a packet distribution rule, in addition to the above-described distribution destination fixing rule, there is also a random rule that distributes packets at random.
[0264]
When this random rule is applied, when a start packet, an intermediate packet, and an end packet corresponding to the same session are sequentially received by the distribution device 300 (see FIG. 1), the start packet, the intermediate packet, and the end packet Since the distribution destination is determined at random, the distribution destination of each packet is different and session disconnection occurs.
[0265]
Therefore, even when the random rule is applied, it is necessary to have a configuration for randomly determining the distribution destination for each session and distributing the start packet, intermediate packet, and end packet corresponding to the same session to the same distribution destination. . Hereinafter, this configuration example will be described as a third embodiment.
[0266]
FIG. 24 is a block diagram showing a configuration of a load distribution system to which the third exemplary embodiment of the present invention is applied. In this figure, parts corresponding to those in FIG. 1 are given the same reference numerals and explanation thereof is omitted. In FIG. 24, a distribution device 800 is provided instead of the distribution device 300 shown in FIG.
[0267]
FIG. 25 is a block diagram showing the configuration of the sorting apparatus 800 shown in FIG. In this figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. 25, an old rule application unit 801 and a new rule application unit 802 are provided instead of the old rule application unit 305 and the new rule application unit 306 shown in FIG. In the distribution apparatus 800, a distribution destination information holding unit 803 is newly provided.
[0268]
When receiving the received packet data from the client-side packet receiving unit 301, the old rule applying unit 801 determines a distribution destination based on the old rule, and notifies the distribution destination determining unit 307 of the obtained distribution destination identifier. In the old rule application unit 801, it is assumed that a random rule for randomly distributing packets in session units is set as an old rule.
[0269]
Further, when a packet of a session that has not been distributed in the past (in this case, a start packet) is received, the old rule application unit 801 distributes the start packet according to the old rule (random rule). After notifying the determination unit 307, the “distribution rule”, “transmission source IP address”, “transmission source port number”, “transmission destination IP address”, “transmission destination port number” and “distribution destination IP” shown in FIG. The distribution destination information consisting of “address” is stored in the distribution destination information holding unit 803.
[0270]
In the distribution destination information, “transmission source IP address”, “transmission source port number”, “transmission destination IP address”, and “transmission destination port number” are the session identifiers stored in the new session identifier database 304 shown in FIG. It corresponds to.
[0271]
The “distribution rule” is a distribution rule (random rule B ′ in the figure) applied to a packet of a session that has not been distributed in the past (in this case, a start packet). The “distribution destination IP address” is a distribution destination (higher layer device 500) determined by applying the “distribution rule”.₁~ 500_ThreeAny one of the higher layer devices).
[0272]
In addition, when a packet of a session that has been distributed in the past (in this case, an intermediate packet or an end packet) is received, the old rule application unit 801 uses the distribution rule (old rule) and the session identifier as keys to distribute The distribution destination IP address is searched from the information holding unit 803. The old rule application unit 801 notifies the distribution destination determination unit 307 of the distribution destination IP address of the search result as the distribution destination of the packet.
[0273]
When receiving the received packet data from the client-side packet receiving unit 301, the new rule applying unit 802 determines a distribution destination using the new rule, and notifies the distribution destination determination unit 307 of the obtained distribution destination identifier. In the new rule application unit 802, a random rule for randomly distributing packets is set as a new rule.
[0274]
Further, when a packet of a session that has not been distributed in the past (in this case, a start packet) is received, the new rule application unit 802 distributes the distribution destination of the start packet according to the new rule (random rule) After notifying the determination unit 307, the “distribution rule”, “transmission source IP address”, “transmission source port number”, “transmission destination IP address”, “transmission destination port number” and “distribution destination IP” shown in FIG. The distribution destination information consisting of “address” is stored in the distribution destination information holding unit 803.
[0275]
In addition, when a packet of a session that has been distributed in the past (in this case, a halfway packet or an end packet) is received, the new rule application unit 802 uses the distribution rule (new rule) and the session identifier as keys as a distribution destination. The distribution destination IP address is searched from the information holding unit 803. The new rule application unit 802 notifies the distribution destination determination unit 307 of the distribution destination IP address of the search result as the distribution destination of the packet.
[0276]
Next, in the same manner as in the first embodiment, the client 100 shown in FIG.₁And 100₂And higher layer device 500₁And 500₂The operation when packet communication is performed in the sequence shown in FIG. 9 will be described.
[0277]
In the operation of the third embodiment in FIG. 9, a case where packets are randomly distributed in session units will be described. Specifically, packet 1 and packet 3 corresponding to the existing session 1 are distributed to the same distribution destination by the random rule B ′, and packet 4, packet 5 and packet 6 corresponding to the new session are the same by the random rule C ′. A case of distribution to the distribution destination will be described.
[0278]
Here, it is assumed that <Random Rule A '> (not shown) is set as the packet distribution rule in the old rule application unit 801 of the distribution apparatus 300 shown in FIG. On the other hand, it is assumed that the above-described <random rule B ′> (see FIG. 26) is set in the new rule application unit 802 as a packet distribution rule.
[0279]
Further, in the sorting device 800, the device state is assumed to be a normal state. Therefore, in this case, the normal state is notified from the maintenance / normal state switching unit 302 to the new / existing session determining unit 303 and the distribution destination determining unit 307.
[0280]
In step SM1 shown in FIG. 27, each of the new rule application unit 802 and the old rule application unit 801 determines whether or not the received packet data is passed from the client side packet reception unit 301. The result is “No” and the same determination is repeated.
[0281]
(Distribution processing of packet 1 (start packet) in normal state)
In the normal state, in step SA1 shown in FIG.₁Transmits packet 1 (start packet) in the existing session 1. In this packet 1 (start packet), <source IP address> is <101.0.0.1>, <source port number> is <200>, <destination IP address> is <200.0.0.10>, <destination Port number> is set to <80>.
[0282]
In step SA2, packet 1 (start packet) is received by the client-side packet receiver 301 of the distribution apparatus 800 shown in FIG. 25 via the Internet 200 shown in FIG.
[0283]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet reception unit 301 determines whether or not the received packet 1 (start packet) corresponds to the maintenance request. In this case, the determination result is “No”.
[0284]
In step SB5, the client side packet receiving unit 301 converts the received packet 1 (start packet) into received packet data, and the new / existing session determining unit 303, the old rule applying unit 801, the new rule applying unit 802, and the server side After passing to the packet transmission unit 308, the determination of step SB1 is performed.
[0285]
When the received packet data (packet 1 (start packet)) is passed from the client side packet receiving unit 301, the new / existing session determination unit 303 sets the determination result of step SD1 shown in FIG. In step SD <b> 2, the new / existing session determination unit 303 checks the device state based on the notification from the maintenance / normal state switching unit 302. In this case, the apparatus state is a normal state.
[0286]
In step SD3, the new / existing session determination unit 303 determines whether or not the apparatus state is a maintenance state. In this case, the determination result is “No” and the determination in step SD1 is performed.
[0287]
When the received packet data (packet 1 (start packet)) is passed from the client side packet receiving unit 301, the old rule applying unit 801 sets “Yes” as a result of the determination made at step SM1 shown in FIG.
[0288]
In step SM2, the old rule application unit 801 uses the currently set distribution rule (in this case, the random rule A ′) and the session identifier included in the packet 1 (start packet) as keys, and the distribution destination information holding unit 803. Check if there is an entry in.
[0289]
In step SM3, the old rule application unit 801 determines whether there is an entry in the distribution destination information holding unit 803. In this case, the determination result is “No”. In step SM4, the old rule application unit 801 applies the currently set random rule A ′ and randomly assigns the assignment destination (for example, the higher layer device 500)._ThreeIP address <200.0.0.3>).
[0290]
In step SM5, the old rule application unit 801 adds an entry (distribution destination information) to the distribution destination information holding unit 803. In step SM6, the old rule application unit 801 notifies the distribution destination to the distribution destination determination unit 307, and then performs the determination in step SM1.
[0291]
When the received packet data (packet 1 (start packet)) is passed from the client side packet receiving unit 301, the new rule applying unit 802 sets “Yes” as a result of the determination made at step SM1 shown in FIG.
[0292]
In step SM2, the new rule application unit 802 uses the currently set distribution rule (in this case, the random rule B ′) and the session identifier included in the packet 1 (start packet) as keys, and the distribution destination information holding unit 803. Check if there is an entry in.
[0293]
In step SM3, the new rule application unit 802 determines whether there is an entry in the distribution destination information holding unit 803, and in this case, the determination result is “No”. In step SM4, the new rule application unit 802 applies the currently set random rule B ', and randomly assigns it to a distribution destination (for example, the higher layer device 500).₁IP address <200.0.0.1>).
[0294]
In step SM5, the new rule application unit 802 adds an entry (distribution destination information) corresponding to the “distribution rule” (random rule B ′) illustrated in FIG. 26 to the distribution destination information holding unit 803. In step SM6, the new rule application unit 802 notifies the distribution destination to the distribution destination determination unit 307, and then performs the determination in step SM1.
[0295]
The distribution destination from the old rule application unit 801 (higher layer device 500)_ThreeIP address <200.0.0.3>) and the distribution destination from the new rule application unit 802 (higher layer device 500)₁) Is notified to the distribution destination determination unit 307, the distribution destination determination unit 307 sets “Yes” as a result of the determination made at step SG1 shown in FIG.
[0296]
In step SG2, the distribution destination determination unit 307 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “Yes”. And
[0297]
In step SG5, the distribution destination determination unit 307 determines the distribution destination (higher layer device 500) notified from the new rule application unit 802.₁IP address <200.0.0.1>) is determined as a distribution destination of the packet 1 (start packet) and notified to the server-side packet transmission unit 308, and then the determination in step SG1 is performed.
[0298]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0299]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 307. In this case, the determination result is “Yes”.
[0300]
In step SH3, the server-side packet transmitter 308 updates the header of packet 1 (start packet) corresponding to the received packet data, and generates packet 1 (start packet) for transmission. Specifically, the server-side packet transmission unit 308 assigns the distribution destination (higher layer apparatus 500) notified from the new rule application unit 802.₁<Destination IP address> of packet 1 (start packet) is rewritten from <200.0.0.10> to <200.0.0.1>.
[0301]
In step SH4, the server-side packet transmission unit 308 distributes the packet 1 (start packet) generated in step SH3 in the existing session 1 (see FIG. 9) to the higher layer apparatus 500 that is the distribution destination.₁After transmitting to (see step SA3 in FIG. 9), the determination in step SH1 is performed.
[0302]
(Maintenance request by packet 2)
In step SA4 shown in FIG. 9, the network administrator changes the distribution rule in the distribution device 300 from the current random rule B ′ to the random rule C ′, and the network administrator terminal 400 shown in FIG. Make a maintenance request using.
[0303]
As a result, the network administrator terminal 400 transmits the packet 2 corresponding to the maintenance request to the distribution device 800. In step SA5 illustrated in FIG. 9, the packet 2 is received by the client-side packet reception unit 301 of the distribution device 800.
[0304]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 2 corresponds to the maintenance request. In this case, the determination result is “Yes”.
[0305]
In step SB3, the client side packet receiving unit 301 notifies the new rule applying unit 802 of the random rule C ′ as the new rule. As a result, a random rule C ′ is set as a new rule in the new rule application unit 802.
[0306]
Further, the new rule application unit 802 notifies the old rule application unit 801 of the random rule B ′ set before the random rule C ′ is set. As a result, the random rule B ′ is set as the old rule in the old rule application unit 801.
[0307]
In step SB4, the client side packet receiving unit 301 passes the maintenance start signal to the maintenance / normal state switching unit 302, and then performs the determination in step SB1.
[0308]
When the maintenance start signal is received, the maintenance / normal state switching unit 302 sets “Yes” as a result of the determination made at step SC1 shown in FIG. In step SC2, the maintenance / normal state switching unit 302 notifies the new / existing session determination unit 303 and the distribution destination determination unit 307 that the current device state is the maintenance state.
[0309]
In step SC3, the maintenance / normal state switching unit 302 determines whether or not a maintenance end signal is passed from the timer 309. In this case, the determination result is “No” and the determination in step SC1 is performed.
[0310]
(Distribution of packet 3 in the maintenance state)
In the maintenance state, at step SA6 shown in FIG.₁Transmits packet 3 (end packet) in the same existing session 1 as packet 1 (start packet) described above. In this packet 3 (end packet), similarly to the above-described packet 1 (start packet), <source IP address> is <101.0.0.1>, <source port number> is <200>, <destination <IP address> is set to <200.0.0.10>, and <destination port number> is set to <80>.
[0311]
In step SA7, the packet 3 (end packet) is received by the client side packet receiving unit 301 of the distribution apparatus 800 shown in FIG. 25 via the Internet 200 shown in FIG.
[0312]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 3 (end packet) corresponds to the maintenance request. In this case, the determination result is “No”.
[0313]
In step SB5, the client side packet receiving unit 301 converts the received packet 3 (end packet) into received packet data, and the new / existing session determining unit 303, the old rule applying unit 801, the new rule applying unit 802, and the server side. After passing to the packet transmission unit 308, the determination of step SB1 is performed.
[0314]
When the received packet data (packet 3 (end packet)) is passed from the client side packet reception unit 301, the new / existing session determination unit 303 sets the determination result in step SD1 shown in FIG. In step SD <b> 2, the new / existing session determination unit 303 checks the device state based on the notification from the maintenance / normal state switching unit 302. In this case, the apparatus state is a maintenance state.
[0315]
In step SD3, the new / existing session determination unit 303 determines whether or not the apparatus state is a maintenance state. In this case, the determination result is “Yes”. In step SD4, the new / existing session determination unit 303 executes a maintenance state process.
[0316]
Specifically, in step SE1 shown in FIG. 13, the new / existing session determination unit 303 determines the session identifier (<source IP address> = <101.0.0.1>, <source port> of packet 3 (end packet). Number> = <200>, <destination IP address> = <200.0.0.10>, <destination port number> = <80>) as a key, and the new session identifier database 304 is searched and is the same as the above session identifier Check for entry.
[0317]
In step SE2, the new / existing session determination unit 303 determines whether there is an entry in the new session identifier database 304 that is the same as the entry identifier of packet 3 (end packet). In this case, the determination result is “No”. "
[0318]
In step SE3, the new / existing session determination unit 303 determines whether or not the packet 3 (end packet) is a session start packet from ON / OFF of the SYN flag of the packet 3 (end packet). In this case, if the SYN flag of packet 3 (end packet) is set to OFF, the new / existing session determination unit 303 sets the determination result in step SE4 to “No”.
[0319]
In step SE7, the new / existing session determination unit 303 transmits a reset signal to the timer 309. Upon receiving the reset signal, the timer 309 starts counting down for a preset time (for example, 15 seconds).
[0320]
In step SE8, the new / existing session determination unit 303 notifies the distribution destination determination unit 307 that the session of packet 3 (end packet) is an existing session, and then determines the determination in step SD1 shown in FIG. Do.
[0321]
When the received packet data (packet 3 (end packet)) is passed from the client side packet receiving unit 301, the old rule applying unit 801 sets “Yes” as a result of the determination made at step SM1 shown in FIG.
[0322]
In step SM2, the old rule application unit 801 uses the currently set distribution rule (in this case, the random rule B ′) and the session identifier included in the packet 3 (end packet) as keys, and the distribution destination information holding unit 803. Check if there is an entry in.
[0323]
In this case, the distribution destination information holding unit 803 shown in FIG. 26 stores a session identifier of the packet 3 and an entry (distribution destination information) corresponding to the “distribution rule” (random rule B ′).
[0324]
In step SM3, the old rule application unit 801 determines whether there is an entry in the distribution destination information holding unit 803. In this case, the determination result is “Yes”. In step SM7, the old rule application unit 801 reads the distribution destination information corresponding to the “distribution rule” (random rule B ′) from the distribution destination information holding unit 803.
[0325]
In step SM6, the old rule application unit 801 determines the distribution destination (higher layer apparatus 500 from the distribution destination information).₁IP address <200.0.0.1>) is acquired and the distribution destination is notified to the distribution destination determination unit 307, and then the determination in step SM1 is performed.
[0326]
When the received packet data (packet 3 (end packet)) is passed from the client side packet receiving unit 301, the new rule applying unit 802 sets “Yes” as a result of the determination made at step SM1 shown in FIG.
[0327]
In step SM2, the new rule applying unit 802 uses the currently set distribution rule (in this case, the random rule B ′) and the session identifier included in the packet 3 (end packet) as keys, and the distribution destination information holding unit 803. Check if there is an entry in.
[0328]
In step SM3, the new rule application unit 802 determines whether there is an entry in the distribution destination information holding unit 803, and in this case, the determination result is “No”. In step SM4, the new rule application unit 802 applies the currently set random rule C ′ and randomly distributes the distribution destination (for example, the higher layer device 500).₂IP address <200.0.0.2>).
[0329]
In step SM5, the new rule application unit 802 adds an entry (distribution destination information) corresponding to the “distribution rule” (random rule C ′) illustrated in FIG. 26 to the distribution destination information holding unit 803. In step SM6, the new rule application unit 802 notifies the distribution destination to the distribution destination determination unit 307, and then performs the determination in step SM1.
[0330]
The distribution destination from the old rule application unit 801 (higher layer device 500)₁IP address <200.0.0.1>) and the distribution destination from the new rule application unit 802 (higher layer device 500)₂Are assigned to the distribution destination determination unit 307, the distribution destination determination unit 307 sets “Yes” as a result of the determination made at step SG1 shown in FIG.
[0331]
In step SG2, the distribution destination determination unit 307 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “No”. And
[0332]
In step SG3, the distribution destination determination unit 307 determines whether the session of the packet 3 (end packet) is an existing session based on the notification (new session or existing session) from the new / existing session determination unit 303. In this case, the determination result is “Yes”.
[0333]
In step SG4, the distribution destination determination unit 307 determines the distribution destination (higher layer apparatus 500) notified from the old rule application unit 801.₁IP address <200.0.0.1>) is determined as a distribution destination of the packet 3 (end packet) and notified to the server-side packet transmission unit 308, and then the determination in step SG1 is performed.
[0334]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0335]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 307. In this case, the determination result is “Yes”.
[0336]
In step SH3, the server-side packet transmitter 308 updates the header of the packet 3 (end packet) corresponding to the received packet data, and generates a packet 3 (end packet) for transmission. Specifically, the server-side packet transmission unit 308 sends the distribution destination (higher layer device 500) notified from the old rule application unit 801.₁<Destination IP address> of packet 3 (end packet) is rewritten from <200.0.0.10> to <200.0.0.1>.
[0337]
In step SH4, the server-side packet transmission unit 308 transmits the packet 3 (end packet) generated in step SH3 in the existing session 1 (see FIG. 9) to the same distribution layer as packet 1 (start packet). Device 500₁After transmitting to (see step SA8 in FIG. 9), the determination in step SH1 is performed.
[0338]
(Distribution of packet 4 (start packet) in maintenance state)
Then, in the maintenance state, in step SA9 shown in FIG.₂Transmits a packet 4 (start packet) in a new session 2 different from the existing sessions 1 of the packets 1 and 3 described above. In this packet 4 (start packet), <source IP address> is <102.0.0.1>, <source port number> is <300>, <destination IP address> is <200.0.0.10>, <destination Port number> is set to <80>.
[0339]
In step SA10, the packet 4 (start packet) is received by the client side packet receiving unit 301 of the distribution device 800 shown in FIG. 25 via the Internet 200 shown in FIG.
[0340]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 4 (start packet) corresponds to the maintenance request. In this case, the determination result is “No”.
[0341]
In step SB5, the client side packet receiving unit 301 converts the received packet 4 (start packet) into received packet data, and the new / existing session determining unit 303, the old rule applying unit 801, the new rule applying unit 802, and the server side After passing to the packet transmission unit 308, the determination of step SB1 is performed.
[0342]
When the received packet data (packet 4 (start packet)) is passed from the client-side packet receiving unit 301, the new / existing session determining unit 303 sets the determination result in step SD1 shown in FIG. In step SD <b> 2, the new / existing session determination unit 303 checks the device state based on the notification from the maintenance / normal state switching unit 302. In this case, the apparatus state is a maintenance state.
[0343]
In step SD3, the new / existing session determination unit 303 determines whether or not the apparatus state is a maintenance state. In this case, the determination result is “Yes”. In step SD4, the new / existing session determination unit 303 executes a maintenance state process.
[0344]
Specifically, in step SE1 shown in FIG. 13, the new / existing session determination unit 303 determines the session identifier (<source IP address> = <102.0.0.1>, <source port> of packet 4 (start packet). Number> = <300>, <destination IP address> = <200.0.0.10>, <destination port number> = <80>) as a key, and searches for a new session identifier database 304, which is the same as the above session identifier. Check for entry.
[0345]
In step SE2, the new / existing session determination unit 303 determines whether there is an entry in the new session identifier database 304 that is identical to the session identifier of the packet 4 (start packet). In this case, the determination result is “No”. "
[0346]
In step SE3, the new / existing session determining unit 303 determines whether or not the packet 4 (start packet) is a session start packet from the ON / OFF state of the SYN flag of the packet 4 (start packet). In this case, if the SYN flag of packet 4 (start packet) is set to ON, the new / existing session determination unit 303 sets the determination result in step SE4 to “Yes”.
[0347]
In step SE5, the new / existing session determination unit 303 adds an entry to the new session identifier database 304. Specifically, the new / existing session determination unit 303 determines the session identifier (<source IP address> = <102.0.0.1>, <source port number> = <300>, <transmission of the packet 4 (start packet). (Destination IP address> = <200.0.0.10>, <destination port number> = <80>) is added to the new session identifier database 304 as an entry.
[0348]
In step SE6, the new / existing session determination unit 303 notifies the distribution destination determination unit 307 that the session of packet 4 (start packet) is a new session, and then determines the determination in step SD1 shown in FIG. Do.
[0349]
When the received packet data (packet 4 (start packet)) is passed from the client side packet receiving unit 301, the old rule applying unit 801 sets “Yes” as a result of the determination made at step SM1 shown in FIG.
[0350]
In step SM2, the old rule application unit 801 uses the currently set distribution rule (in this case, the random rule B ′) and the session identifier included in the packet 4 (start packet) as keys, and the distribution destination information holding unit 803. Check if there is an entry in.
[0351]
In step SM3, the old rule application unit 801 determines whether there is an entry in the distribution destination information holding unit 803. In this case, the determination result is “No”. In step SM4, the old rule applying unit 801 applies the currently set random rule B ', and randomly assigns the assignment destination (for example, the higher layer device 500).₁IP address <200.0.0.1>).
[0352]
In step SM5, the old rule application unit 801 adds an entry (distribution destination information) to the distribution destination information holding unit 803. In step SM6, the old rule application unit 801 notifies the distribution destination to the distribution destination determination unit 307, and then performs the determination in step SM1.
[0353]
When the received packet data (packet 4 (start packet)) is passed from the client side packet receiving unit 301, the new rule applying unit 802 sets “Yes” as a result of the determination made at step SM1 shown in FIG.
[0354]
In step SM2, the new rule application unit 802 uses the currently set distribution rule (in this case, the random rule C ′) and the session identifier included in the packet 4 (start packet) as keys, and the distribution destination information holding unit 803. Check if there is an entry in.
[0355]
In step SM3, the new rule application unit 802 determines whether there is an entry in the distribution destination information holding unit 803, and in this case, the determination result is “No”. In step SM4, the new rule application unit 802 applies the currently set random rule C ′ and randomly distributes the distribution destination (for example, the higher layer device 500).₂IP address <200.0.0.2>).
[0356]
In step SM5, the new rule application unit 802 adds an entry (distribution destination information) corresponding to the “distribution rule” (random rule C ′) illustrated in FIG. 26 to the distribution destination information holding unit 803. In step SM6, the new rule application unit 802 notifies the distribution destination to the distribution destination determination unit 307, and then performs the determination in step SM1.
[0357]
The distribution destination from the old rule application unit 801 (higher layer device 500)₁IP address <200.0.0.1>) and the distribution destination from the new rule application unit 802 (higher layer device 500)₂Are assigned to the distribution destination determination unit 307, the distribution destination determination unit 307 sets “Yes” as a result of the determination made at step SG1 shown in FIG.
[0358]
In step SG2, the distribution destination determination unit 307 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “No”. And
[0359]
In step SG3, the distribution destination determination unit 307 determines whether the session of the packet 4 (start packet) is an existing session based on the notification (new session or existing session) from the new / existing session determination unit 303. In this case, the determination result is “No”.
[0360]
In step SG4, the distribution destination determination unit 307 determines the distribution destination (higher layer device 500) notified from the new rule application unit 802.₂IP address <200.0.0.2>) is determined as a distribution destination of the packet 4 (start packet) and notified to the server-side packet transmission unit 308, and then the determination in step SG1 is performed.
[0361]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0362]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 307. In this case, the determination result is “Yes”.
[0363]
In step SH3, the server-side packet transmitter 308 updates the header of the packet 4 (start packet) corresponding to the received packet data, and generates a packet 4 (start packet) for transmission. Specifically, the server-side packet transmission unit 308 assigns the distribution destination (higher layer apparatus 500) notified from the new rule application unit 802.₂<Destination IP address> of packet 4 (start packet) is rewritten from <200.0.0.10> to <200.0.0.2>.
[0364]
In step SH4, the server-side packet transmission unit 308 distributes the packet 4 (start packet) generated in step SH3 in the new session 2 (see FIG. 9) to the distribution-destination higher layer apparatus 500.₂After transmitting to (see step SA11 in FIG. 9), the determination in step SH1 is performed.
[0365]
(Distribution of packet 5 in maintenance state)
Then, in the maintenance state, in step SA12 shown in FIG.₂Transmits packet 5 (intermediate packet) in the same new session 2 as packet 4 (start packet) described above. In this packet 5 (intermediate packet), <source IP address> is <102.0.0.1>, <source port number> is <300>, <destination IP address> is <200.0.0.10>, <destination Port number> is set to <80>.
[0366]
In step SA13, the packet 5 (intermediate packet) is received by the client side packet receiving unit 301 of the distribution apparatus 800 shown in FIG. 25 via the Internet 200 shown in FIG.
[0367]
Thereby, the client side packet receiving unit 301 sets “Yes” as a result of the determination made at step SB1 shown in FIG. In step SB2, the client side packet receiving unit 301 determines whether or not the received packet 5 (intermediate packet) corresponds to the maintenance request. In this case, the determination result is “No”.
[0368]
In step SB5, the client side packet receiving unit 301 converts the received packet 5 (intermediate packet) into received packet data, and the new / existing session determining unit 303, the old rule applying unit 801, the new rule applying unit 802, and the server side. After passing to the packet transmission unit 308, the determination of step SB1 is performed.
[0369]
When the received packet data (packet 5 (intermediate packet)) is passed from the client side packet receiving unit 301, the new / existing session determination unit 303 sets the determination result of step SD1 shown in FIG. In step SD <b> 2, the new / existing session determination unit 303 checks the device state based on the notification from the maintenance / normal state switching unit 302. In this case, the apparatus state is a maintenance state.
[0370]
In step SD3, the new / existing session determination unit 303 determines whether or not the apparatus state is a maintenance state. In this case, the determination result is “Yes”. In step SD4, the new / existing session determination unit 303 executes a maintenance state process.
[0371]
Specifically, in step SE1 shown in FIG. 13, the new / existing session determination unit 303 determines the session identifier (<source IP address> = <102.0.0.1>, <source port> of packet 5 (intermediate packet). Number> = <300>, <destination IP address> = <200.0.0.10>, <destination port number> = <80>) as a key, and searches for a new session identifier database 304, which is the same as the above session identifier. Check for entry.
[0372]
In step SE2, the new / existing session determination unit 303 determines whether there is an entry in the new session identifier database 304 that is the same as the session identifier of the packet 5 (intermediate packet). In this case, the determination result is “Yes”. "
[0373]
In step SE6, the new / existing session determination unit 303 notifies the distribution destination determination unit 307 that the session of packet 5 (intermediate packet) is a new session, and then determines the determination in step SD1 shown in FIG. Do.
[0374]
When the received packet data (packet 5 (intermediate packet)) is passed from the client side packet receiving unit 301, the old rule applying unit 801 sets “Yes” as a result of the determination made at step SM1 shown in FIG.
[0375]
In step SM2, the old rule application unit 801 uses the currently set distribution rule (in this case, the random rule B ′) and the session identifier included in the packet 5 (intermediate packet) as keys, and the distribution destination information holding unit 803. Check if there is an entry in.
[0376]
In this case, the distribution destination information holding unit 803 shown in FIG. 26 stores a session identifier of the packet 5 and an entry (distribution destination information) corresponding to the “distribution rule” (random rule B ′).
[0377]
In step SM3, the old rule application unit 801 determines whether there is an entry in the distribution destination information holding unit 803. In this case, the determination result is “Yes”. In step SM7, the old rule application unit 801 reads the distribution destination information corresponding to the “distribution rule” (random rule B ′) from the distribution destination information holding unit 803.
[0378]
In step SM6, the old rule application unit 801 determines the distribution destination (higher layer apparatus 500 from the distribution destination information).₁IP address <200.0.0.1>) is acquired and the distribution destination is notified to the distribution destination determination unit 307, and then the determination in step SM1 is performed.
[0379]
When the received packet data (packet 5 (intermediate packet)) is passed from the client side packet receiving unit 301, the new rule applying unit 802 sets “Yes” as a result of the determination made at step SM1 shown in FIG.
[0380]
In step SM2, the new rule application unit 802 uses the currently set distribution rule (in this case, the random rule C ′) and the session identifier included in the packet 5 (intermediate packet) as keys, and the distribution destination information holding unit 803. Check if there is an entry in.
[0381]
In this case, the distribution destination information holding unit 803 shown in FIG. 26 stores a session identifier of the packet 5 and an entry (distribution destination information) corresponding to the “distribution rule” (random rule C ′).
[0382]
In step SM3, the new rule application unit 802 determines whether or not there is an entry in the distribution destination information holding unit 803. In this case, the determination result is “Yes”. In step SM7, the new rule application unit 802 reads distribution destination information corresponding to the “distribution rule” (random rule C ′) from the distribution destination information holding unit 803.
[0383]
In step SM6, the new rule application unit 802 determines the distribution destination (higher layer device 500) from the distribution destination information.₂IP address <200.0.0.2>) is acquired and the distribution destination is notified to the distribution destination determination unit 307, and then the determination at step SM1 is performed.
[0384]
The distribution destination from the old rule application unit 801 (higher layer device 500)₁IP address <200.0.0.1>) and the distribution destination from the new rule application unit 802 (higher layer device 500)₂Are assigned to the distribution destination determination unit 307, the distribution destination determination unit 307 sets “Yes” as a result of the determination made at step SG1 shown in FIG.
[0385]
In step SG2, the distribution destination determination unit 307 determines whether or not the current device state is the normal state based on the notification from the maintenance / normal state switching unit 302. In this case, the determination result is “No”. And
[0386]
In step SG3, the distribution destination determination unit 307 determines whether the session of the packet 5 (intermediate packet) is an existing session based on the notification (new session or existing session) from the new / existing session determination unit 303. In this case, the determination result is “No”.
[0387]
In step SG4, the distribution destination determination unit 307 determines the distribution destination (higher layer device 500) notified from the new rule application unit 802.₂IP address <200.0.0.2>) is determined as a distribution destination of the packet 5 (intermediate packet) and notified to the server-side packet transmission unit 308, and then the determination in step SG1 is performed.
[0388]
When the received packet data is passed from the client side packet receiving unit 301, the server side packet transmitting unit 308 sets “Yes” as a result of the decision made at step SH1 shown in FIG.
[0389]
In step SH2, the server-side packet transmission unit 308 determines whether or not the distribution destination is notified from the distribution destination determination unit 307. In this case, the determination result is “Yes”.
[0390]
In step SH3, the server-side packet transmitter 308 updates the header of the packet 5 (intermediate packet) corresponding to the received packet data, and generates a transmission packet 5 (intermediate packet). Specifically, the server-side packet transmission unit 308 assigns the distribution destination (higher layer apparatus 500) notified from the new rule application unit 802.₂<Destination IP address> of packet 5 (intermediate packet) is rewritten from <200.0.0.10> to <200.0.0.2>.
[0390]
In step SH4, the server-side packet transmission unit 308 transmits the packet 5 (intermediate packet) generated in step SH3 in the new session 2 (see FIG. 9) to the same high-order layer as the packet 4 (start packet). Device 500₂After transmitting to (see step SA14 in FIG. 9), the determination in step SH1 is performed.
[0392]
When the countdown of the timer 309 becomes 0, in step SA15 shown in FIG. 9, the timer 309 transmits a maintenance end signal to the maintenance / normal state switching unit 302 to end the maintenance.
[0393]
When the maintenance end signal is received, the maintenance / normal state switching unit 302 sets “Yes” as a result of the determination made at step SC3 shown in FIG. In step SC4, the maintenance / normal state switching unit 302 notifies the new / existing session determination unit 303 and the distribution destination determination unit 307 that the current apparatus state is the normal state.
[0394]
As a result, the new / existing session determination unit 303 deletes all entries in the new session identifier database 304 because the current apparatus state has changed from the maintenance state to the normal state.
[0395]
(Distribution of packet 6 in normal state)
In the normal state, in step SA16 shown in FIG.₂Transmits packet 6 (end packet) in the same new session 2 as packet 4 (start packet) and packet 5 (intermediate packet) described above. In this packet 6 (end packet), <source IP address> is <102.0.0.1>, <source port number> is <300>, <destination IP address> is <200.0.0.10>, <destination Port number> is set to <80>.
[0396]
In step SA17, the packet 6 (end packet) is received by the client side packet receiving unit 301 of the distribution apparatus 800 shown in FIG. 25 via the Internet 200 shown in FIG.
[0397]
Thereafter, through the above-described operation, the packet 6 (end packet) corresponding to the new session 2 is similarly assigned to the same distribution destination (high order packet) as the packet 4 (start packet) and packet 5 (intermediate packet) corresponding to the new session 2. Layer device 500₂IP address <200.0.0.2>).
[0398]
As described above, according to the third embodiment, in the random rule, the distribution destination information of the distribution destination information of the old rule (existing session distribution destination information) and the distribution destination information of the new rule (new session distribution destination information). If the session is determined to be an existing session, the traffic corresponding to the existing session is allocated based on the existing session allocation destination information, while the session is a new session. If it is determined that the traffic corresponding to the new session is distributed based on the new session distribution destination information, the traffic can be distributed on a session basis even with the random rule.
[0399]
(Embodiment 4)
In the first embodiment described above, the configuration example in which the client-side packet reception unit 301 illustrated in FIG. 2 has a function of outputting a maintenance start signal and a distribution rule has been described. The component which implement | achieves automatically may be provided. Hereinafter, this configuration example will be described as a fourth embodiment.
[0400]
FIG. 28 is a block diagram showing a configuration of a load distribution system to which the fourth exemplary embodiment of the present invention is applied. In this figure, parts corresponding to those in FIG. 1 are given the same reference numerals and explanation thereof is omitted. In FIG. 28, a distribution device 900 is provided instead of the distribution device 300 shown in FIG.
[0401]
FIG. 29 is a block diagram showing the configuration of the sorting apparatus 900 shown in FIG. In this figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. 29, a client side packet receiving unit 901 is provided instead of the client side packet receiving unit 301 shown in FIG. In the distribution apparatus 900, a maintenance request control unit 902 is newly provided.
[0402]
The client-side packet receiving unit 901 receives the client 100 shown in FIG.₁And 100₂1 is received via the Internet 200, and the packet is converted into received packet data in a format that can be internally processed by the distribution device 900, and then passed to each unit.
[0403]
In addition, when receiving a maintenance request packet (see FIG. 3A) from the network administrator terminal 400 (see FIG. 28), the client-side packet receiving unit 901 passes this packet to the maintenance request control unit 902.
[0404]
When the maintenance request control unit 902 receives a maintenance request packet from the client-side packet reception unit 901, the maintenance request control unit 902 passes the distribution rule corresponding to the distribution rule type to the new rule application unit 306 as a new rule.
Further, the maintenance request control unit 902 has a function of holding a subsequent packet until the processing of the previous packet is completed when the next maintenance request packet is further received in the maintenance state after receiving the maintenance request packet. It has.
[0405]
When the processing of the previous packet is completed, the maintenance request control unit 902 executes processing for notifying a maintenance start signal and a distribution rule corresponding to the subsequent packet. Thereby, in Embodiment 4, a maintenance request can be received continuously.
[0406]
Next, in the same manner as in the first embodiment, the client 100 shown in FIG.₁And 100₂And higher layer device 500₁And 500₂The operation when packet communication is performed in the sequence shown in FIG. 9 will be described.
[0407]
The operation of the fourth embodiment in FIG. 9 is almost the same as the operation of the first embodiment, but the difference in operation between the first and fourth embodiments in the case of the maintenance request packet 2. Appears. Therefore, in the following, the case of packet 2 will be described in detail.
[0408]
(Maintenance request by packet 2)
In step SA4 shown in FIG. 9, the network administrator changes the distribution rule in the distribution device 900 from the current rule B (see FIG. 5B) to the rule C (see FIG. 5C). A maintenance request is issued using the network administrator terminal 400 shown in FIG.
[0409]
Here, in step SN1 shown in FIG. 30, the maintenance request control unit 902 determines whether or not a maintenance request packet is passed from the client side packet receiving unit 901. In this case, the determination result is “No”. Repeat the same judgment.
[0410]
Then, the packet 2 corresponding to the maintenance request is transmitted from the network administrator terminal 400 to the distribution device 900. In step SA5 shown in FIG. 9, the packet 2 is received by the client-side packet receiving unit 901 of the distribution apparatus 900.
[0411]
The client side packet receiving unit 901 passes the packet 2 to the maintenance request control unit 902 because the received packet 2 corresponds to the maintenance request. Accordingly, the maintenance request control unit 902 sets “Yes” as a result of the determination made at step SN1 shown in FIG.
[0412]
In step SN 2, maintenance request control section 902 passes a maintenance start signal corresponding to packet 2 to maintenance / normal state switching section 302.
[0413]
When the maintenance start signal is received, the maintenance / normal state switching unit 302 sets “Yes” as a result of the determination made at step SC1 shown in FIG. Thereafter, the processing after step SC2 described above is executed.
[0414]
In step SN3 shown in FIG. 30, the maintenance request control unit 902 notifies the new rule application unit 306 of the rule C (see FIG. 5C) as a new rule, and then makes a determination in step SN1. Thereby, the rule C is set as a new rule in the new rule application unit 306.
[0415]
Also, the new rule application unit 306 notifies the old rule application unit 305 of the rule B (see FIG. 5B) set before the rule C is set. As a result, the rule B is set as the old rule in the old rule application unit 305.
[0416]
Subsequently, a packet 2 ′ (not shown) corresponding to the maintenance request is transmitted from the network administrator terminal 400 to the distribution device 900. This packet 2 ′ is received by the client side packet receiving unit 901 of the distribution apparatus 900. Here, since the client side packet receiving unit 901 is executing the maintenance request for the packet 2 first, the client side packet receiving unit 901 holds the received packet 2 ′ and requests the maintenance of the packet 2 ′ after the processing corresponding to the packet 2 is completed. It passes to the control unit 902. Thereafter, as described above, the process is executed every time a packet is received.
[0417]
As described above, according to the fourth embodiment, when a maintenance request packet is continuously received by the client-side packet reception unit 901, the maintenance request control unit 902 performs processing corresponding to the previous maintenance request packet. Is executed, and after the processing corresponding to the previous maintenance request packet is completed, the processing corresponding to the subsequent maintenance request packet is executed. Since the maintenance requests can be sequentially processed, frequent rule changes can be handled.
[0418]
(Embodiment 5)
In the first embodiment described above, the configuration example in which the maintenance end signal is generated by the timer 309 shown in FIG. 2 has been described. However, instead of the timer 309, the maintenance end signal is replaced by a component that measures the end timing. It is good also as a structure which produces | generates. Hereinafter, this configuration example will be described as a fifth embodiment.
[0419]
FIG. 31 is a block diagram showing a configuration of a load distribution system to which the fifth exemplary embodiment of the present invention is applied. In this figure, parts corresponding to those in FIG. 1 are given the same reference numerals and explanation thereof is omitted. In FIG. 31, a distribution device 1000 is provided instead of the distribution device 300 shown in FIG.
[0420]
FIG. 32 is a block diagram showing the configuration of the sorting apparatus 1000 shown in FIG. In this figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.
[0421]
32, instead of the maintenance / normal state switching unit 302, the timer 309, and the new / existing session determination unit 303 shown in FIG. 2, a maintenance / normal state switching unit 1001, an end timing measuring unit 1002, and a new / existing session are included. A determination unit 1003 is provided.
[0422]
When the maintenance start signal is passed from the client side packet receiving unit 301, the maintenance / normal state switching unit 1001 notifies the distribution destination determining unit 307 and the new / existing session determining unit 1003 of the maintenance state.
[0423]
The maintenance / normal state switching unit 1001 passes the measurement start signal to the end timing measurement unit 1002 when the maintenance start signal is passed. Also, when the maintenance / normal state switching unit 1001 receives a maintenance end signal from the end timing measuring unit 1002, the maintenance / normal state switching unit 1001 notifies the distribution destination determining unit 307 and the new / existing session determining unit 1003 of the normal state.
[0424]
When the measurement start signal is passed from the maintenance / normal state switching unit 1001, the end timing measuring unit 1002 measures time until the set time elapses, and the end timing of the maintenance state, that is, the device state is changed from the maintenance state to the normal state. Measure the timing to enter the state.
[0425]
Next, in the same manner as in the first embodiment, the client 100 shown in FIG.₁And 100₂And higher layer device 500₁And 500₂The operation when packet communication is performed in the sequence shown in FIG. 9 will be described.
[0426]
The operation of the fifth embodiment in FIG. 9 is almost the same as the operation of the first embodiment, but the difference in operation between the first and fifth embodiments in the case of the maintenance request packet 2. Appears. Therefore, in the following, the case of packet 2 will be described in detail.
[0427]
(Maintenance request by packet 2)
In step SA4 shown in FIG. 9, the network administrator changes the distribution rule in the distribution apparatus 1000 from the current rule B (see FIG. 5B) to the rule C (see FIG. 5C). A maintenance request is issued using the network administrator terminal 400 shown in FIG.
[0428]
Here, in step SO1 shown in FIG. 33, the maintenance / normal state switching unit 1001 determines whether or not a maintenance start signal is passed from the client side packet receiving unit 301. In this case, the determination result is “No”. And In step SO4, the maintenance / normal state switching unit 1001 determines whether a maintenance end signal is passed from the end timing measurement unit 1002, and in this case, the determination result is “No”. Thereafter, the determinations in steps SO1 and SO4 are repeated until the determination result is “Yes”.
[0429]
In step SP1 shown in FIG. 34, the end timing measurement unit 1002 determines whether or not a measurement start signal is passed from the maintenance / normal state switching unit 1001, and in this case, the determination result is “No”. Repeat the same judgment.
[0430]
Then, the packet 2 corresponding to the maintenance request is transmitted from the network administrator terminal 400 to the distribution apparatus 1000. In step SA5 illustrated in FIG. 9, the packet 2 is received by the client-side packet reception unit 301 of the distribution apparatus 1000.
[0431]
The client side packet receiving unit 301 passes a maintenance start signal to the maintenance / normal state switching unit 1001 because the received packet 2 corresponds to the maintenance request. Thereby, the maintenance / normal state switching unit 1001 sets “Yes” as a result of the determination made at step SO1 shown in FIG.
[0432]
In step SO2, the maintenance / normal state switching unit 1001 notifies the distribution destination determination unit 307 and the new / existing session determination unit 1003 of the maintenance state. In step SO3, the maintenance / normal state switching unit 1001 passes a measurement start signal to the end timing measuring unit 1002.
[0433]
In step SO4, the maintenance / normal state switching unit 1001 determines whether or not a maintenance end signal has been passed from the end timing measurement unit 1002, and in this case, the determination result is “No” and the determination in step SO1 is performed.
[0434]
Further, when the measurement start signal is passed from the maintenance / normal state switching unit 1001, the end timing measurement unit 1002 sets “Yes” as a result of the determination made at step SP1 shown in FIG. In step SP2, the end timing measuring unit 1002 starts measuring time. In step SP3, the end timing measurement unit 1002 determines whether or not the set time has elapsed. In this case, the determination result is “No” and the determination is repeated.
[0435]
When the determination result in step SP3 is “Yes”, in step SP4, the end timing measurement unit 1002 passes a maintenance end signal to the maintenance / normal state switching unit 1001.
[0436]
Thereby, the maintenance / normal state switching unit 1001 sets “Yes” as a result of the determination made at step SO4 shown in FIG. In step SO5, the maintenance / normal state switching unit 1001 notifies the distribution destination determination unit 307 and the new / existing session determination unit 1003 of the normal state, and then performs the determination in step SO1.
[0437]
As described above, according to the fifth embodiment, the client side packet reception unit 301 receives a maintenance request packet for changing a rule, and receives a measurement start signal from the maintenance / normal state switching unit 1001. Since a maintenance end signal for ending the combination period is passed from the end timing measuring unit 1002 to the maintenance / normal state switching unit 1001 after a predetermined time has elapsed from the previous session, an existing session is monitored by a simple method of monitoring the elapse of the predetermined time. Can prevent cutting.
[0438]
(Embodiment 6)
In the first embodiment described above, the client 100 is shown in FIG.₁And 100₂And a higher layer device group 501 are provided with a distribution device 300, and the client 100₁And 100₂However, it is also possible to provide a distribution device between the higher layer device group 501 and the server group 601 to distribute packets from the server group 601. Hereinafter, this configuration example will be described as a sixth embodiment.
[0439]
FIG. 35 is a block diagram showing a configuration of a load distribution system to which the sixth exemplary embodiment of the present invention is applied. In this figure, parts corresponding to those in FIG. 1 are given the same reference numerals and explanation thereof is omitted.
[0440]
35, a distribution device 1100 is provided instead of the distribution device 300 shown in FIG. In FIG. 35, a distribution device 1200 is newly provided between the higher layer device group 501 and the server group 601.
[0441]
The distribution apparatus 1100 is similar to the distribution apparatus 300 (see FIG. 1), and the client 100₁And 100₂Packets from the higher layer device 500 according to the distribution rule₁~ 500_ThreeIs provided with a function of allocating to any one of the higher layer devices.
[0442]
The distribution apparatus 1100 also has a function of transmitting a maintenance request packet from the network administrator terminal 400 to the distribution apparatus 1200 and synchronizing the maintenance start timing with the distribution apparatus 1200. Here, in the sixth embodiment, in the maintenance request packet, a time at which maintenance is simultaneously started by the distribution device 1100 and the distribution device 1200 is set as a synchronization time.
[0443]
FIG. 36 is a block diagram showing a configuration of the sorting apparatus 1100 shown in FIG. In this figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.
[0444]
36, a client side packet receiving unit 1101 is provided instead of the client side packet receiving unit 301 shown in FIG. In the distribution apparatus 1100, a maintenance request packet transmission unit 1102, a maintenance request control unit 1103, and a synchronization timing measurement unit 1104 are newly provided.
[0445]
The client-side packet receiving unit 1101 is the client 100 shown in FIG.₁And 100₂1 is received via the Internet 200, and the packet is converted into received packet data in a format that can be internally processed by the distribution apparatus 1100, and then passed to each unit.
[0446]
When the client side packet receiving unit 1101 receives a maintenance request packet (see FIG. 3A) from the network administrator terminal 400 (see FIG. 35), the client side packet receiving unit 1101 sends the packet to the maintenance request packet transmitting unit 1102 and the maintenance request packet. The request is transferred to the request control unit 1103.
[0447]
The maintenance request packet transmission unit 1102 has a function of transmitting a maintenance request packet passed from the client side packet reception unit 1101 to the distribution device 1200 (see FIG. 35).
[0448]
When the maintenance request control unit 1103 receives a maintenance request packet from the client side packet reception unit 1101, the maintenance request control unit 1103 passes the distribution rule corresponding to the distribution rule type to the new rule application unit 306 as a new rule.
[0449]
The maintenance request control unit 1103 notifies the synchronization timing measurement unit 1104 of the synchronization time set in the maintenance request packet. Further, when a start instruction is issued from the synchronization timing measurement unit 1104, the maintenance request control unit 1103 passes a maintenance start signal to the maintenance / normal state switching unit 302.
[0450]
The synchronization timing measurement unit 1104 has a function of measuring the synchronization timing between the distribution device 1100 and the distribution device 1200. When the time of an internal timer (not shown) becomes the synchronization time notified from the maintenance request control unit 1103. Then, a start instruction for instructing the maintenance request control unit 1103 to start maintenance is issued.
[0451]
The distribution device 1200 shown in FIG. 35 is substantially the same as the configuration of the distribution device 1100 (see FIG. 36) described above. However, the distribution device 1200 is not provided with a component corresponding to the maintenance request packet transmission unit 1102 (see FIG. 36).
[0452]
Next, in the same manner as in the first embodiment, the client 100 shown in FIG.₁And 100₂And higher layer device 500₁And 500₂The operation when packet communication is performed in the sequence shown in FIG. 9 will be described.
[0453]
The operation of the sixth embodiment in FIG. 9 is substantially the same as the operation of the first embodiment, but the difference in operation between the first and sixth embodiments in the case of the maintenance request packet 2. Appears. Therefore, in the following, the case of packet 2 will be described in detail.
[0454]
(Maintenance request by packet 2)
In step SA4 shown in FIG. 9, the network administrator changes the distribution rule in the distribution device 1100 from the current rule B (see FIG. 5B) to rule C (see FIG. 5C). A maintenance request is issued using the network administrator terminal 400 shown in FIG.
[0455]
Here, in step SQ1 shown in FIG. 37, the client-side packet receiving unit 1101 determines whether or not a packet has been received. In this case, the determination result is “No” and the determination is repeated.
[0456]
In step SR1 shown in FIG. 38, the maintenance request control unit 1103 determines whether or not a maintenance request packet is passed from the client side packet reception unit 1101, and in this case, the determination result is “No”. Repeat the same judgment.
[0457]
Then, the packet 2 corresponding to the maintenance request is transmitted from the network administrator terminal 400 to the distribution apparatus 1100. It is assumed that a synchronization time is set in this packet 2.
[0458]
In step SA5 illustrated in FIG. 9, the packet 2 is received by the client-side packet reception unit 1101 of the distribution device 1100. As a result, the client-side packet receiving unit 1101 sets “Yes” as a result of the determination made at step SQ1 shown in FIG.
[0459]
In step SQ2, it is determined whether or not the packet 2 corresponds to the maintenance request. In this case, the determination result is “Yes”. If the determination result in step SQ2 is “No”, in step SQ4, the client side packet receiving unit 1101 converts the packet into received packet data and passes it to each unit.
[0460]
In step SQ3, the client side packet receiving unit 1101 transfers the maintenance request packet 2 to the maintenance request packet transmitting unit 1102 and the maintenance request control unit 1103, and then performs the determination in step SQ1.
[0461]
The maintenance request packet transmission unit 1102 transmits the maintenance request packet 2 to the distribution device 1200 (see FIG. 35). When the maintenance request packet 2 is passed, the maintenance request control unit 1103 sets “Yes” as a result of the determination made at step SR1 shown in FIG.
[0462]
In step SR2, the maintenance request control unit 1103 notifies the synchronization timing measurement unit 1104 of the synchronization time set in the maintenance request packet 2. In step SR3, the maintenance request control unit 1103 determines whether or not there is a start instruction from the synchronization timing measurement unit 1104. In this case, the determination result is “No” and the determination is repeated.
[0463]
Then, the synchronization timing measurement unit 1104 issues a start instruction to the maintenance request control unit 1103 when the internal timer reaches the synchronization time notified from the maintenance request control unit 1103.
[0464]
Accordingly, the maintenance request control unit 1103 sets “Yes” as a result of the determination made at step SR3 shown in FIG. In step SR4, the maintenance request control unit 1103 passes a maintenance start signal to the maintenance / normal state switching unit 302. Thereby, in the distribution device 1100, at the synchronization time, the device state shifts from the normal state to the maintenance state, and the maintenance is started.
[0465]
In step SR5, the maintenance request control unit 1103 notifies the rule C (see FIG. 5C) as a new rule to the new rule application unit 306, and then makes a determination in step SR1. Thereby, the rule C is set as a new rule in the new rule application unit 306.
[0466]
Also, the new rule application unit 306 notifies the old rule application unit 305 of the rule B (see FIG. 5B) set before the rule C is set. As a result, the rule B is set as the old rule in the old rule application unit 305.
[0467]
On the other hand, when the maintenance request packet 2 is received from the distribution apparatus 1100 to the distribution apparatus 1200 (see FIG. 35), the distribution apparatus 1200 also executes the processing described in FIG. 37 and FIG. At the synchronized time, the apparatus state shifts from the normal state to the maintenance state, and maintenance starts.
[0468]
As described above, according to the sixth embodiment, the maintenance for changing the rule from the distribution device 1100 to the distribution device 1200 (opposite side distribution device) provided on the opposite side across the higher layer device group 501 is performed. Since the request packet is transmitted, it is possible to distribute the upstream and downstream traffic to the higher layer apparatus group 501 without disconnecting the session.
[0469]
Further, according to the sixth embodiment, since the packet including the synchronization time for simultaneously executing the rule change is transmitted from the distribution device 1100 to the distribution device 1200 (opposite distribution device), the synchronization of the rule change start is performed. Can take.
[0470]
Although Embodiments 1 to 6 according to the present invention have been described in detail with reference to the drawings, specific configuration examples are not limited to these Embodiments 1 to 6 and depart from the gist of the present invention. Even if there is a design change within a range not to be included, it is included in the present invention.
[0471]
For example, in the first to sixth embodiments described above, the distribution device 300 (see FIG. 2), the distribution device 700 (see FIG. 18), the distribution device 800 (see FIG. 25), the distribution device 900 (see FIG. 29), the distribution A program for realizing the functions of the device 1000 (see FIG. 32), the sorting device 1100 (see FIG. 36), or the sorting device 1200 (see FIG. 35) is recorded on the computer-readable recording medium 1400 shown in FIG. Each function may be realized by causing the computer 1300 shown in the figure to read and execute the program recorded in the recording medium 1400.
[0472]
A computer 1300 shown in the figure includes a CPU (Central Processing Unit) 1310 that executes the above-described program, an input device 1320 such as a keyboard and a mouse, a ROM (Read Only Memory) 1330 that stores various data, an operation parameter, and the like RAM (Random Access Memory) 1340, a reading device 1350 for reading a program from a recording medium 1400, an output device 1360 such as a display and a printer, and a bus 1370 for connecting each part of the device.
[0473]
The CPU 1310 implements the above-described functions by reading a program recorded on the recording medium 1400 via the reading device 1350 and then executing the program. Note that examples of the recording medium 1400 include an optical disk, a flexible disk, and a hard disk.
[0474]
Further, in the first to sixth embodiments, the illustrated configuration is an example and is not intended to exclude other configurations, and a part of the illustrated configuration may be replaced with another or illustrated configuration Other configurations obtained by omitting a part of the above, adding another function to the illustrated configuration, combining them, and the like are also possible.
[0475]
In the first to sixth embodiments, another configuration that is logically equivalent to the illustrated configuration, another configuration that includes a portion that is logically equivalent to the illustrated configuration, and logical parts of the illustrated configuration are logically included. Other equivalent configurations are possible.
[0476]
(Appendix 1)
A session that receives a distribution rule change request for distributing traffic to a distribution destination device group, and determines whether the traffic session is an existing session established before the rule change request or a new session established after the rule change request Judgment means,
When the session determining means determines that the session is the existing session, traffic is distributed to the distribution destination device group according to a distribution rule before the rule change request, while the session is the new session. If it is determined, according to the distribution rule after the rule change request, a distribution means for distributing traffic to the distribution destination device group,
Distribution control program to function as
[0477]
(Supplementary Note 2) The session determination means holds a new session identifier for identifying the new session established after the rule change request, and collates the new session identifier with a session identifier included in the traffic. The distribution control program according to supplementary note 1, wherein the determination is performed as described above.
[0478]
(Supplementary note 3) The computer functions as a combined period setting means for ending the combined period in which the distribution rule before the rule change request and the distribution rule after the rule change request are used together after the existing session is normally terminated The distribution control program according to appendix 1 or 2, characterized in that:
[0479]
(Supplementary note 4) The combined period setting means measures the arrival interval of traffic corresponding to the existing session, and terminates the combined period assuming that the existing session has ended normally when the arrival interval reaches a set time. The distribution control program according to attachment 3, wherein the distribution control program is executed.
[0480]
(Supplementary note 5) The distribution control program according to supplementary note 3, wherein the combination period setting unit terminates the combination period after a predetermined time has elapsed since the rule change request was received.
[0481]
(Appendix 6) The session determination means applies a distribution destination to which a distribution rule before the rule change request is applied and a distribution rule after the rule change request to the traffic generated after the rule change request. When the distribution destination is the same, the determination is not performed, and when the distribution destination is the same, the distribution unit distributes the traffic based on the distribution destination to which the distribution rule after the rule change request is applied. 6. The distribution control program according to any one of appendices 1 to 5, wherein the distribution control program is distributed to a device group.
[0482]
(Additional remark 7) The said distribution rule is a random rule which distributes traffic at random, The existing session distribution destination information regarding the traffic corresponding to the said existing session initially distributed according to the random rule before the said rule change request | requirement, and the said rule And distribution destination information holding means for holding new session distribution destination information related to traffic corresponding to the new session initially distributed according to the random rule after the change request, and the distribution means includes the session determination means, When it is determined that the session is the existing session, traffic corresponding to the existing session is distributed based on the existing session distribution destination information, while it is determined that the session is the new session. If, on the basis of the new session distribution destination information, distribution control program according to any one of Appendices 1 to 6, characterized in that for distributing traffic corresponding to the new session.
[0483]
(Additional remark 8) When the said rule change request | requirement was continuous, the process corresponding to a previous rule change request is performed, the subsequent rule change request is hold | maintained, and the process corresponding to the said previous rule change request The distribution control program according to any one of appendices 1 to 7, further comprising: a control unit that executes a process corresponding to the subsequent rule change request after the process is completed.
[0484]
(Supplementary note 9) The computer is caused to function as a request notification unit that notifies a request for changing the rule to a counter-side distribution device provided on a side opposite to the distribution destination device group. The distribution control program according to any one of 1 to 8.
[0485]
(Supplementary note 10) The distribution control program according to supplementary note 9, wherein the request notification means notifies the opposing distribution device of the time at which the rule change is executed simultaneously.
[0486]
(Appendix 11) In response to a distribution rule change request for distributing traffic to a distribution destination device group, whether the traffic session is an existing session established before the rule change request or a new session established after the rule change request Session determination means for determining
When the session determining means determines that the session is the existing session, traffic is distributed to the distribution destination device group according to a distribution rule before the rule change request, while the session is the new session. When it is determined, according to the distribution rule after the rule change request, a distribution unit that distributes traffic to the distribution destination device group,
A distribution control device comprising:
[0487]
(Supplementary Note 12) The session determination unit holds a new session identifier for identifying the new session established after the rule change request, and collates the new session identifier with a session identifier included in the traffic. The distribution control device according to supplementary note 11, wherein the determination is made as described above.
[0488]
(Additional remark 13) It was provided with the combined period setting means to complete | finish the combined period which uses together the distribution rule before the said rule change request, and the distribution rule after the said rule change request, after the said existing session is completed normally 13. The distribution control device according to Supplementary Note 11 or 12,
[0489]
(Supplementary note 14) The combined period setting means measures the arrival interval of traffic corresponding to the existing session, and terminates the combined period assuming that the existing session has ended normally when the arrival interval reaches a set time. 14. The distribution control device according to appendix 13, wherein
[0490]
(Supplementary note 15) The distribution control device according to supplementary note 13, wherein the combination period setting unit terminates the combination period after a predetermined time has elapsed after receiving the rule change request.
[0491]
(Supplementary Note 16) For the traffic generated after the rule change request, the session determination unit has applied a distribution destination to which a distribution rule before the rule change request is applied and a distribution rule after the rule change request is applied. When the distribution destination is the same, the determination is not performed, and when the distribution destination is the same, the distribution unit distributes the traffic based on the distribution destination to which the distribution rule after the rule change request is applied. The distribution control device according to any one of appendices 11 to 15, wherein the distribution control device is distributed to a device group.
[0492]
(Additional remark 17) The said distribution rule is a random rule which distributes traffic at random, The existing session distribution destination information regarding the traffic corresponding to the said existing session initially distributed according to the random rule before the said rule change request | requirement, and the said rule And distribution destination information holding means for holding new session distribution destination information related to traffic corresponding to the new session initially distributed according to the random rule after the change request, and the distribution means includes the session determination means, If it is determined that the session is the existing session, traffic corresponding to the existing session is distributed based on the existing session distribution destination information, while the session is determined to be the new session. When the new session based on the distribution destination information, distribution control apparatus according to any one of Appendices 11 to 16, characterized in that for distributing traffic corresponding to the new session.
[0493]
(Additional remark 18) When the said rule change request | requirement was continuously, the process corresponding to a previous rule change request is performed, the subsequent rule change request is hold | maintained, and the process corresponding to the said previous rule change request The distribution control device according to any one of appendices 11 to 17, further comprising: a control unit that executes processing corresponding to the subsequent rule change request after completion of the process.
[0494]
(Supplementary note 19) Supplementary notes 11 to 18, further comprising request notifying means for notifying a request for changing the rule to the opposing distribution device provided on the opposite side across the distribution destination device group. The distribution control device according to any one of the above.
[0495]
(Supplementary note 20) The distribution control device according to supplementary note 19, wherein the request notifying unit notifies the opposing distribution device of times for simultaneously executing the rule change.
[0496]
(Appendix 21) In response to a distribution rule change request for distributing traffic to a distribution destination device group, whether the traffic session is an existing session established before the rule change request or a new session established after the rule change request A session determination process for determining
When the session determination step determines that the session is the existing session, traffic is distributed to the distribution destination device group according to a distribution rule before the rule change request, while the session is the new session If it is determined, according to the distribution rule after the rule change request, a distribution step of distributing traffic to the distribution destination device group,
A distribution control method comprising:
[0497]
(Supplementary Note 22) In the session determination step, a new session identifier for identifying the new session established after the rule change request is held, and the new session identifier is compared with the session identifier included in the traffic. 23. The distribution control method according to appendix 21, wherein the determination is performed as described above.
[0498]
(Supplementary Note 23) A combination period setting step of ending a combination period in which the distribution rule before the rule change request and the distribution rule after the rule change request are used together after the existing session is normally ended is included. The distribution control method according to appendix 21 or 22,
[0499]
(Supplementary Note 24) In the combined period setting step, the arrival interval of traffic corresponding to the existing session is measured, and when the arrival interval reaches a set time, the existing period ends normally, and the combined period ends. 24. The distribution control method according to attachment 23, wherein the distribution control method is performed.
[0500]
(Supplementary note 25) The distribution control method according to supplementary note 23, wherein, in the combined period setting step, the combined period is ended after a predetermined time has elapsed since the rule change request was received.
[0501]
(Supplementary note 26) In the session determination step, a distribution destination to which a distribution rule before the rule change request is applied and a distribution rule after the rule change request are applied to the traffic generated after the rule change request. If the distribution destination is the same, the determination is not performed, and in the distribution step, if the same, the traffic is routed to the distribution destination based on the distribution destination to which the distribution rule after the rule change request is applied. 26. The distribution control method according to any one of appendices 21 to 25, wherein the distribution control method distributes to a device group.
[0502]
(Supplementary note 27) The distribution rule is a random rule that distributes traffic at random, the existing session distribution destination information related to traffic corresponding to the existing session that is initially distributed according to the random rule before the rule change request, and the rule A distribution destination information holding step for holding new session distribution destination information related to traffic corresponding to the new session initially distributed according to the random rule after the change request, and in the distribution step, the session determination step, If it is determined that the session is the existing session, traffic corresponding to the existing session is distributed based on the existing session distribution destination information, while the session is determined to be the new session. If it is, on the basis of the new session distribution destination information, distribution control method according to any one of Appendices 21-26, characterized in that for distributing traffic corresponding to the new session.
[0503]
(Additional remark 28) When the said rule change request | requirement has been continuous, the process corresponding to a previous rule change request is performed, the subsequent rule change request is hold | maintained, and the process corresponding to the said previous rule change request 28. The distribution control method according to any one of appendices 21 to 27, further comprising: a control step of executing a process corresponding to the subsequent rule change request after completion of.
[0504]
(Additional remark 29) The request notification process of notifying the request | requirement for changing the said rule to the opposing distribution apparatus provided in the other side on both sides of the said allocation destination apparatus group of the additional remarks 21-28 characterized by the above-mentioned The distribution control method according to any one of the above.
[0505]
(Supplementary note 30) The distribution control method according to supplementary note 29, wherein, in the request notification step, the opposite side distribution device is notified of a time at which the rule change is executed simultaneously.
[0506]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent session disconnection for changing a distribution rule without increasing the processing load of a traffic distribution destination and the consumption of network bandwidth.
[0507]
In addition, according to the present invention, it is possible to speed up the distribution process when the distribution destination to which the distribution rule before the rule change request is applied and the distribution destination to which the distribution rule after the rule change request is applied are the same. There is an effect that can be.
[0508]
In addition, according to the present invention, there is an effect that traffic can be distributed on a session basis even with a random rule.
[0509]
In addition, according to the present invention, since a plurality of requests can be processed sequentially, there is an effect that it is possible to cope with frequent rule changes.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a load distribution system to which a first embodiment according to the present invention is applied.
FIG. 2 is a block diagram showing a configuration of a sorting apparatus 300 shown in FIG.
FIG. 3 is a diagram showing a format and an example of a maintenance request (packet) in the first embodiment.
FIG. 4 is a diagram for explaining the operation principle of the first embodiment.
FIG. 5 is a diagram showing a distribution rule applied in the first to sixth embodiments according to the present invention.
6 is a diagram showing a table structure of a new session identifier database 304 shown in FIG. 2. FIG.
FIG. 7 is a diagram for explaining the operation principle of the first embodiment.
FIG. 8 is a diagram for explaining a correspondence relationship between a packet type and a distribution rule in the first embodiment.
FIG. 9 is a sequence diagram for explaining the operation of the load distribution system to which the first to sixth embodiments are applied.
10 is a flowchart for explaining the operation of the client side packet reception unit 301 shown in FIG.
11 is a flowchart for explaining the operation of the maintenance / normal state switching unit 302 shown in FIG. 2;
12 is a flowchart for explaining the operation of a new / existing session determination unit 303 shown in FIG.
13 is a flowchart illustrating the maintenance state process shown in FIGS. 12 and 20. FIG.
14 is a flowchart for explaining operations of a new rule application unit 306 and an old rule application unit 305 shown in FIG.
15 is a flowchart for explaining the operation of a distribution destination determination unit 307 shown in FIG.
16 is a flowchart for explaining the operation of the server-side packet transmission unit 308 shown in FIG.
FIG. 17 is a block diagram showing a configuration of a load distribution system to which the second exemplary embodiment of the present invention is applied.
18 is a block diagram showing a configuration of a sorting apparatus 700 shown in FIG.
FIG. 19 is a diagram showing a rule B in the second embodiment.
20 is a flowchart for explaining the operation of a new / existing session determination unit 701 shown in FIG.
FIG. 21 is a flowchart for explaining operations of a new rule application unit 703 and an old rule application unit 702 shown in FIG. 18;
22 is a flowchart for explaining the operation of a distribution destination comparing unit 705 shown in FIG.
23 is a flowchart for explaining the operation of a distribution destination determination unit 704 shown in FIG.
FIG. 24 is a block diagram showing a configuration of a load distribution system to which the third exemplary embodiment of the present invention is applied.
25 is a block diagram showing a configuration of a sorting apparatus 800 shown in FIG.
26 is a diagram showing a table structure of a distribution destination information holding unit 803 shown in FIG.
27 is a flowchart for explaining operations of a new rule application unit 802 and an old rule application unit 801 shown in FIG.
FIG. 28 is a block diagram showing a configuration of a load distribution system to which the fourth exemplary embodiment of the present invention is applied.
29 is a block diagram showing a configuration of a sorting apparatus 900 shown in FIG.
30 is a flowchart for explaining the operation of the maintenance request control unit 902 shown in FIG. 29. FIG.
FIG. 31 is a block diagram showing a configuration of a load distribution system to which a fifth embodiment according to the present invention is applied;
32 is a block diagram showing a configuration of a sorting apparatus 1000 shown in FIG. 31. FIG.
33 is a flowchart for explaining the operation of the maintenance / normal state switching unit 1001 shown in FIG. 32;
34 is a flowchart for explaining the operation of the end timing measuring unit 1002 shown in FIG. 32. FIG.
FIG. 35 is a block diagram showing a configuration of a load distribution system to which a sixth embodiment according to the present invention is applied.
36 is a block diagram showing a configuration of the sorting apparatus 1100 shown in FIG. 35. FIG.
FIG. 37 is a flowchart for explaining the operation of the client side packet receiving unit 1101 shown in FIG. 36;
38 is a flowchart for explaining the operation of the maintenance request control unit 1103 shown in FIG. 36.
FIG. 39 is a block diagram showing a configuration of a modified example of the first to sixth embodiments.
FIG. 40 is a block diagram showing a configuration of a conventional star-type load distribution system.
[Explanation of symbols]
100₁, 100₂  client
300 Sorting device
301 Client side packet receiver
302 Maintenance / normal state switching unit
303 New / Existing Session Judgment Section
305 Old Rule Application Department
306 New Rule Application Department
307 Sorting destination determination unit
501 Higher layer device group
601 server group
700 Sorting device
701 New / Existing Session Judgment Section
702 Old Rule Application Department
703 New Rule Application Department
704 Distribution destination determination unit
705 Distribution comparison unit
800 Sorting device
801 Old Rule Application Department
802 New Rule Application Department
900 Sorting device
901 Client side packet receiver
902 Maintenance request control unit
1000 sorter
1001 Maintenance / normal state switching part
1002 End timing measurement unit
1100 Sorting device
1101 Client side packet receiver
1102 Maintenance request packet transmitter
1103 Maintenance Request Control Unit
1104 Synchronization timing measurement unit
1200 Sorting device

Claims (5)

A session that receives a distribution rule change request for distributing traffic to a distribution destination device group, and determines whether the traffic session is an existing session established before the rule change request or a new session established after the rule change request Judgment means,
When the session determining means determines that the session is the existing session, traffic is distributed to the distribution destination device group according to a distribution rule before the rule change request, while the session is the new session. When it is determined, according to the distribution rule after the rule change request, a distribution unit that distributes traffic to the distribution destination device group,
A distribution control device comprising: The session determination means holds a new session identifier for identifying the new session established after the rule change request, and collates the new session identifier with a session identifier included in the traffic, thereby The distribution control device according to claim 1, wherein the determination is performed. The session determination means includes a distribution destination to which a distribution rule before the rule change request is applied and a distribution destination to which a distribution rule after the rule change request is applied for the traffic generated after the rule change request. If they are the same, the determination is not performed, and if the same, the distribution unit distributes the traffic to the distribution destination device group based on a distribution destination to which the distribution rule after the rule change request is applied. The distribution control device according to claim 1 or 2, wherein The distribution rule is a random rule that randomly distributes traffic, existing session distribution destination information related to traffic corresponding to the existing session first distributed according to the random rule before the rule change request, and after the rule change request Distribution destination information holding means for holding new session distribution destination information relating to traffic corresponding to the new session initially distributed according to a random rule, wherein the distribution means is configured to determine whether the session is the existing session by the session determination means. When it is determined that it is a session, traffic corresponding to the existing session is distributed based on the existing session distribution destination information, while when it is determined that the session is the new session, Serial based on the new session distribution destination information, distribution control device according to any one of claims 1 to 3, characterized in that for distributing traffic corresponding to the new session. When there is a continuous rule change request, the process corresponding to the previous rule change request is executed, the subsequent rule change request is retained, and the process corresponding to the previous rule change request is completed The distribution control device according to claim 1, further comprising: a control unit that executes a process corresponding to the subsequent rule change request.

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