JP3093545B2 - Packet routing method of inter-station link control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a routing control system in an inter-station link control packet switching network.

[0002]

2. Description of the Related Art Conventionally, a routing system of this type is configured such that when a relay station having a plurality of routes is connected in tandem and a packet is transferred between terminals, all the relay stations perform packet-by-packet processing.
A relay station is selected with reference to a provided route selection table, and routing is performed to a called station.

[0003]

In the conventional routing method described above, every time a relay station receives a packet, it refers to a route selection table of its own station, selects a relay station to be transferred, and routes to a destination station. Therefore, the packet transfer delay from the source station to the destination station is large, and when the source station transmits a plurality of consecutive packets, each relay station selects a relay station for each packet and transfers it. There is a very high possibility that the receiving station changes the order of the transmitted packets and arrives at the receiving station, and the receiving station must always control the order of the incoming packets and then transmit the incoming packets to the called terminal. .

An object of the present invention is to provide a packet routing system of an inter-station link control system capable of transferring packets without selecting a relay station for each packet.

[0005]

According to the present invention, there is provided a packet routing method of an inter-station link control method, which is a routing method of an inter-station control method in which a plurality of packet switches are connected in tandem. A route selection table to be registered and a relay station memory for storing a relay station number including a calling station number and a called station number; for specifying a relay route in a call request packet, a connection completion packet and a data packet to be transferred; At the time of call setup, the calling station that has received the call request packet from the calling terminal refers to the route selection table of the own station, selects a relay route to the called station, and adds the While storing in the relay station memory of the station, the relay station number of the relay route selected in the inter-station header section is set and transmitted in relay order, and transmitted.
The relay station identifies the presence or absence of its own relay station number from the inter-station header part of the call request packet received from the calling station or the connection completion packet received from the called station, and its own relay station number If there is, select a relaying route from the route selection table of the own station to the called station or the calling station, and if there is no relay station number of the own station, the inter-office header section includes the A relay station number is set and transmitted to the called station or the calling station, and the called station relays the relay station number set in the inter-station header part of the received call request packet to the relay station. Stored in station memory,
When the connection completion packet is transmitted, the relay station number is read from the relay station memory of the local station, the inter-station header portion is set and transmitted in a reverse order to the reception, and the transmission station receiving the connection completion packet is The relay station number set in the inter-station header portion of the connection completion packet is updated by comparing it with the relay station number stored in the relay station memory of the own station; Read out the relay station number from the relay station memory of the own station, set the inter-station header portion of the data packet and transmit to the relay station,
The relay station sequentially relays by referring to the inter-station header part of the received data packet, and the receiving station sets the relay station number set in the inter-station header part of the received data packet to the relay station number of the own station. The relay station number stored in the relay station memory of the own station is set in the inter-station header portion of the data packet stored in the relay station memory and returned to the calling station in the order of relay, and is returned to the calling station.

Also, at the time of the data transfer, the relay station number of the relay route selected from the route selection table is set in the inter-station header portion at a predetermined cycle in the same manner as at the time of the call setting, and the call is transmitted to the called station. The receiving station sets the relay station number set in the inter-station header portion of the received data packet in the inter-station header portion when returning the data packet; The relay station memory of the own station is updated based on the relay station number set in the inter-station header section of the data packet returned from the station.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a packet network according to one embodiment of the present invention. FIG. 2 is a diagram showing an example of a relay station memory configuration included in the packet switch of the originating station. FIG. 3 is a diagram showing an example of the configuration of a route selection table provided in each of the packet switches constituting the packet network. FIG. 4 is a flowchart showing the call request packet transfer operation in the call setting phase. FIG. 5 is a flowchart showing the data packet transfer operation in the data transfer phase.

Referring to FIG. 1, in the present embodiment, an outgoing packet terminal P, an incoming packet terminal Q, and packet terminals P and Q
It is composed of a source station A, relay stations B and C, and a packet network of a destination station D connecting between them.

Next, referring to FIG. 1 to FIG.
A routing operation when a packet is transferred from the packet terminal to the packet terminal Q will be described. In order to transfer a packet from the packet terminal P to the packet terminal Q, a call request packet (packet 1) shown in FIG. The transmitting station A receives the call request packet (packet 1) as shown in FIG. 4 (S100), and identifies whether or not this packet is a data transfer phase packet (S101). If the packet is in the data transfer phase, it is determined whether or not it is a predetermined timing for checking the normality of the relay station memory (S10).
2) Do it. Unless it is time to check the accuracy Figure 5
Shifts to the data transfer phase shown in FIG. The timing to confirm this normality is that it is necessary to change the route when the initially set route cannot be used due to route failure etc.
In the data transfer phase, the transmitting station A confirms the relay route from the transmitting station A to the receiving station D at a predetermined cycle in the same manner as the call request packet, and is stored in its own relay station memory. The relay station number is monitored and the latest relay route is stored.

The originating station A determines whether the identification result in step S101 is a call request packet,
02 is the timing of the normality check, when the destination station D is selected from the route selection table of the own station shown in FIG.
B, c, d (b, c are relay stations B,
The first route (the second route is b, e, d) of the station number of C and d is the station number of the receiving station D is selected (S103), and the received call request packet or the normality check timing An inter-station header part for designating a relay station is added to the data packet (packet 1), relay station numbers b and c are set in the inter-station header part, and a source station number a and a destination station number d
Is generated, and a call request packet addressed to the destination station D or a data packet (packet 2) at the time of normality confirmation timing is generated and transmitted to the relay station B (S104).

The relay station B identifies whether or not the relay station itself is the receiving station from the inter-station header portion of the call request packet received from the calling station A or the data packet (packet 2) at the time of normality confirmation (S105). ). Since the relay station B is not the receiving station, it is next determined whether or not its own relay station number b is present in the inter-station header section (S106). Then, the first route for the destination station D is selected from the route selection table of the own station, and a call request packet or a data packet (packet 2) at the time of normality confirmation timing is transmitted to the relay station C (S107). Step S
If the relay station number b of the own station cannot be identified in 106, the relay station number b of the own station is set in the inter-station header section (S1).
08) After that, in step S107, the first route is selected from the route selection table of the own station, and a call request packet or a data packet (packet 2) at the time of normality confirmation is transmitted to the relay station C.

Similarly to the relay station B, the relay station C identifies whether or not the own station is the called station from the call request packet received from the relay station B or the data packet (packet 2) at the time of the normality check timing. After (S109), it is identified whether the relay station number c of the own station is set in the inter-station header part (S110).
When the relay station number c of the own station is set, the first route for the destination station D is selected from the route selection table of the own station, and a call request packet to the destination station D or a normality confirmation timing Is transmitted (S1).
11). If the relay station number c of the own station cannot be identified in step S110, the relay station number c of the own station is set in the inter-station header section (S112), and then the step S11 is performed.
In step 1, the first route is selected from the route selection table of the own station, and a call request packet or a data packet (packet 2) at the time of normality confirmation timing is transmitted to the receiving station D.

The receiving station D identifies whether or not it is the receiving station from the received call request packet or the data packet (packet 2) at the time of the normality confirmation timing (S113).
Since it is called station D, it is next identified whether or not its own called station number d is set in the inter-station header section (S114).
When the own station's called station number d is set, the calling station number a, the relay station numbers b and c, and the called station number d set in the inter-station header are stored in the own station's relay station memory. Memory (S
115) After that, the inter-station header portion is removed from the received call request packet or the data packet (packet 2) at the time of normality confirmation timing, and the incoming call packet (packet 1)
Is transmitted to the packet terminal Q (S116). Step S
When the own station is not the called station in 113, and in step S114, the called station number d
If there is no, the process proceeds to step S102.

Subsequently, when the receiving station D receives a call receiving packet or a data packet (packet 1) at the time of normality confirmation returned to the calling station from the packet terminal Q, the receiving station D or the calling station receives the received packet. The inter-station header is added to the data packet (packet 2) at the time of the normality check returned to the transmission station, and the transmission station number a, the transmission station numbers b and c and the transmission station number stored in the relay station memory of the own station are added. d is read out, and the destination station number d,
The transmission station number a and the relay station numbers c and b are set in this order, and a connection completion packet or a data packet (packet 2) at the time of normality confirmation returned to the transmission station is transmitted to the relay station C. The relay stations C and B perform the same processing as the call request packet shown in FIG.

In this way, a relay route for transmitting from the packet terminal P to the packet terminal Q is set. Thereafter, for the data packet transmitted from the packet terminal P other than the normality confirmation timing, the originating station A reads the relay station number from the relay station memory to the destination station D, sets the relay station number in the inter-station header section, and sets each relay station. The stations B and C relay the data packets in the relay order set by the originating station A in the inter-station header section, and the data packets are transmitted to the terminating packet terminal Q via the terminating station D.

Next, the operation of the data transfer phase other than the normality confirmation timing will be described. When the transmitting station A has identified in step S102 that the timing is not the normality confirmation timing, the transmitting station A adds an inter-station header section to the received data packet (packet 2) and stores the transmitting station number a from the relay station memory of its own station. , Destination station number d and relay station numbers b and c are read and added to the inter-station header section (S
117) and a data packet (packet (packet 2)
Is transmitted to the relay station B (S118). At this time, calling station A
The relay route (first route) to the destination station D in the above-described processing of the call request packet (see FIG. 4) is already stored in the relay station memory.

The receiving station B identifies from the inter-station header section of the received data packet (packet 2) whether or not itself is the receiving station (S119). Since the relay station B is not the receiving station, the relay station B identifies the presence or absence of the relay station number b of its own station in the inter-station header portion of the received data packet (packet 2) (S12).
0) and if the relay station number of the own station is present in the inter-station header section, the data packet (packet 2) is transmitted to the relay station C according to the relay station number c set in the inter-station header section (S12).
1) Yes. If the relay station number b of the own station cannot be identified in the inter-station header section in step S120, the relay station number b of the own station is set in the inter-station header section (S122), and then the route of the own station is determined in step S123. Calling station D from selection table
A route (first route) is selected, and a data packet (packet 2) is transmitted to the relay station C.

The relay station C, like the relay station B, identifies from the data packet (packet 2) received from the relay station B whether or not the own station is the called station (S124), and then stores it in the inter-station header section. The presence or absence of the relay station number c of the own station is identified (S125).
If the relay station number c of the own station is set, the data packet (packet 2) is transmitted to the destination station D according to the destination station number d set in the inter-station header section (S126). If the relay station number c of the own station cannot be identified in step S125, the relay station number of the own station is set in the inter-station header section (S127), and in step S128, the called station is determined from the route selection table of the own station. D is selected and a data packet (packet 2) is transmitted to the receiving station D (S128).

The receiving station D identifies that it is the receiving station from the received data packet (packet 2) (S129).
Then, the receiving station number d of the own station is identified from the inter-station header section (S130), and the transmitting station number a, the relay station numbers b, c and the receiving station number d set in the inter-office header section are identified. After storing it in the relay station memory of the station (S131), the inter-station header portion is removed from the data packet (packet 2), and the data packet (packet 1) is transferred to the packet terminal Q which is the receiving terminal.
(S131).

Subsequently, when receiving the data packet (packet 1) returned from the packet terminal Q to the transmitting station A, the receiving station D adds an inter-station header to the received data packet (packet 1), and The originating station number a, the originating station number b, c, and the terminating station number d stored in the intervening station memory are read, and the terminating station number d, the originating station number a, the originating station number c, b Then, the data packet (packet 2) is transmitted to the relay station C. The relay stations C and B perform the same processing as in the data transfer phase shown in FIG.

[0021]

As described above, according to the present invention, in the call setup phase, when the calling station receives a call request packet,
A route to the called station is selected from the route selection table of the own station, the calling station number, the relay station number, and the called station number of the route are stored in the relay station memory of the own station in the order of relay, and a call request is made. An inter-station header is added to the packet, and the source station number, the relay station number, and the destination station number stored in the relay station memory are set in the relay order in the inter-station header, and transmitted to the relay station. When the relay station number of the own station is not set, the relay station number of the own station is set in the inter-station header section, transmitted to the called station, and the called station is set in the inter-station header section of the received call request packet. The originating station number, the relay station number, and the called station number stored in the relay station memory of the own station, and the originating station number, the relay station number, and the Set the receiving station number, return to the calling station, and call Is the source station number, relay station number, and destination station number set in the inter-station header part of the received connection completion packet, and the source station number, relay station number, and destination station number stored in the relay station memory of the own station. The relay route is set by comparing with and updating. After that, in the data transfer phase, the source station number, relay station number and destination station number stored in the relay station memory at the source station are set in the inter-station header part. The data is transmitted to the relay station, and the relay station transfers the data packets in the order of the relay station number specified in the inter-station header portion of the data packet without performing the route selection processing. Every station can perform routing without having to refer to the route selection table and select a relay station each time, which reduces packet transfer delay and reduces the effects of the packet network. It can be.

Further, since the forwarding route to be transferred is substantially fixed, even if the transmitting station transmits a plurality of continuous packets, the possibility that the order of the transmitted packets is changed and the incoming packet arrives becomes very low. There is also an effect that efficient packet transfer that does not require order control can be performed.

Further, in the data transfer phase, the relay route initially set (at the time of a call request packet) is checked at a predetermined cycle while transferring data, and if a route failure occurs, the relay station memory is automatically stored in the relay station memory. Since updating is performed, a stable packet transfer service can always be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a packet network according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a relay station memory of an originating station according to the present invention.

FIG. 3 is a diagram showing a configuration of a route selection table according to the present invention.

FIG. 4 is a flowchart of a call setup phase of the present invention.

FIG. 5 is a flowchart of a data transfer phase of the present invention.

[Explanation of symbols]

 A Calling station B, C, E Relay station D Calling station P Calling packet terminal Q Calling packet terminal

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-2760 (JP, A) JP-A-5-7224 (JP, A) JP-A-4-84542 (JP, A) JP-A-4-845 47736 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/56 H04L 12/28

Claims (2)

(57) [Claims] In a routing system of an inter-station control system in which a plurality of packet switches are connected in tandem, the packet switches each include a route selection table for registering a relay route, and a relay station including a source station number and a destination station number. A relay station memory for storing numbers; an interoffice header for specifying a relay route is added to the call request packet, connection completion packet and data packet to be transferred;
The calling station that has received the call request packet from the calling terminal refers to the route selection table of its own station, selects a relay route to a called station, stores it in its own relay station memory, and stores The relay station number of the relay route selected in the inter-header section is set and transmitted in the relay order, and the relay station transmits the call request packet received from the calling station or the connection completion packet received from the called station. Identify the presence or absence of the relay station number of the own station from the inter-station header portion, and when the relay station number of the own station is present, select the relay route to the receiving station or the calling station from the route selection table of the own station. If the relay station number of the own station does not exist, the relay station number of the own station is set in the inter-station header section, and the relay station number is transmitted to the receiving station or the transmitting station. The interoffice header part of a call request packet The set relay station number is stored in the relay station memory of the own station, and the relay station number is read from the relay station memory of the own station at the time of transmitting the connection completion packet, and the same is received in the inter-station header section in reverse to the time of reception. The transmitting station set and transmitted in the order of, and the transmitting station receiving the connection completion packet stores the relay station number set in the inter-station header portion of the connection completion packet in the relay station memory of the own station. When transmitting data, the transmitting station reads the relay station number from the relay station memory of its own station and sets the read relay station number in the inter-station header section of the data packet. And the relay station sequentially relays the received data packet with reference to the inter-station header section of the received data packet, and the called station sets the relay set in the inter-station header section of the received data packet. The number is stored in the relay station memory of the own station, and the relay station number stored in the relay station memory of the own station is set in the relay station memory of the own station in the inter-station header portion of the data packet returned to the originating station. A packet routing method of an inter-station link control method, which is returned to a source station. 2. At the time of the data transfer, the relay station number of the relay route selected from the route selection table is set in the inter-station header section at a predetermined cycle in the same manner as at the time of the call setting, and the call is transmitted to the called station. The receiving station sets the relay station number set in the inter-station header portion of the received data packet in the inter-station header portion when returning the data packet; 2. The inter-station link according to claim 1, wherein the relay station memory of the own station is updated based on the relay station number set in the inter-station header section of the data packet returned from the station. Packet routing method of control method.