JP3398461B2 - System used in network environment and device implemented in the system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for establishing data connection by establishing a connection with another system via a multiplexed communication path in a network environment, and more particularly to a path where the connection is established. The present invention relates to a system that guarantees continuation of a connection even when an abnormality occurs and a device mounted on the system.

[0002]

2. Description of the Related Art Recently, workstations, personal computers, etc. have been remarkably improved in performance. Along with this, construction of computer networks for connecting these computers to each other by LAN (local area network) or the like has become popular. Has become.

In such a computer network, a form shown in FIG. 23 is known as a form having fall tolerance (fault tolerance).
In the same figure, own system 410 and partner system 420
Two systems are two Ethernet type LAN4
They are mutually connected via 02 and 404. The own system 410 is connected to the LANs 402 and 404 via two LAN adapters 412 and 414, respectively. On the other hand, the partner system 420 receives the LAN 40 via the two LAN adapters 422 and 424.
2, 404.

In such a computer network, for example, the OSI (Open Systems Interconnection) protocol is known as one of network protocols for interconnecting the two systems 410 and 420. ing. This OS
The I protocol defines two transport layer services, a connection-type transport service and a connectionless-type transport service.

Among these, in the connection type transport service, two systems 41 are provided before data transfer.
It is necessary to establish a connection (transport connection) between 0 and 420 in advance. In this connection establishment process, for example, one of the routes defined in the system from the system 410 to the system 420 is set.
A route (when there are a plurality of routes, for example, an optimal route in consideration of load distribution) is selected, and a connection establishment request (T-CONNECT request) by the route is transmitted, and the system 420 confirms the connection (T-CONNECT request). -CONNECT confirmation) is returned to the system 410 to establish the transport connection. Then, after this connection is established, data transfer using the protocol of the transport layer becomes possible between both systems 410 and 420.

[0006]

The method described above [SUMMARY OF THE INVENTION], asterisk 41 in a state where connection to a path through the LAN 402 is established, for example, in FIG. 23
If an abnormality occurs at the place where the LAN adapter 412 on the path indicated by 6 is directly connected, the system 41
The 0 side can detect this abnormality via the LAN adapter 412, but the partner system 420 side cannot detect this abnormality. This applies, for example, to the case where the portion indicated by the star mark 416 is a transceiver attached to the transmission path, and the LAN adapter 412 is connected to the transceiver through a transceiver cable.

In such a case, since the system 420 does not notice this abnormality, the system 410 is set to the route.
It will continue to send data addressed to it, but due to the anomaly, this data will not be sent to system 410. For this reason, the system 420 cannot receive a response to the data transmitted by itself even after the retransmission time has elapsed, and therefore, after repeating the data retransmission process, the connection with the system 410 is disconnected.

[0008] Further, when the system 410 transmits data, the system 420 is also notified of the route change by transmitting the data to the system 420 by another route. That is, in this case, the system 420 changes the route of the connection from route to route by receiving the data via the route instead of the route.

However, in this case, the system 410
Does not know the route definition information on the system 420 side, there is a case where a route change request is made by a route that is not defined on the system 420 side. In this case, there is a problem that the route is not changed.

That is, for example, when the route is defined in the system 410 and the route is defined in the system 420, even if the system 410 detects an abnormality in the route and notifies the route change to the route, the system 420 is detected. Since the route is not defined on the side, the system 420 cannot change the route to the system 410 via this route, and discards the route change request.

Further, when the system 410 makes a route change request through a transmission line to which the system 420 is not connected, this route change request is issued by the system 42.
When the system 420 is waiting for a response because it does not reach 0, the system 420 times out of the inactivity monitoring control time, activates the transport connection release procedure, and disconnects the connection.

As described above, in the conventional network, even if two systems 410 and 420 are connected by a plurality of routes, an abnormality occurs in which only one system 410 can be detected on the route used for the connection. In that case, there is a problem that the connection route is not changed and the connection is disconnected.

Therefore, the reliability of the network is low,
This has been a serious problem especially in networks having fault tolerant functions. Further, such a problem occurs not only when an abnormality occurs in a route, but also when, for example, one system logically deactivates a connection transmission line to a LAN on a route where a connection is established. Was there. The logical deactivation of the connection transmission line is an operation of internally managing the connection transmission line as an unusable state at the time of, for example, maintenance of the system. It is carried out by inactive.

According to the present invention, a connection is established with each other.
Both systems are independently detecting path anomalies.
Then, both systems change their routes to the other system.
Even if the route change request is sent and the route change request collides,
It is to be able to guarantee the continuation of nection.

[0015]

FIG . 1 is a diagram for explaining the principle of systems C and D of the present invention. These systems C and D are used in a network environment, and a plurality of routes are defined with the partner system.

The system C comprises the following means 11, 12,
13 and 14 are provided. The storage means 11 stores whether the own system is a calling side or a called side when a connection is established with the partner system.

The route change request transmission means 12, when the abnormality of the currently used route is detected while the connection is established, selects 1 from the remaining defined routes other than the currently used route. One route is selected, and a route change request is transmitted to the partner system by the route.

The route change request receiving means 13 receives the route change request from the partner system after transmitting the route change request,
Based on the stored information of the storage means 11 at the time of reception, for example,
When it is determined that the own system is the calling side at the time of establishing the connection, the system transits to the route change response waiting state.

The route change confirmation transmitting means 14 receives the route change response from the partner system in the route change response waiting state, and transmits the route change confirmation to the partner system in response to the reception.

On the other hand, the system D has the following means 16,
The storage unit 16 including 17, 18, and 19 stores whether the own system is a calling side or a called side when a connection is established with the partner system.

The route change request transmission means 17 detects one of the remaining routes other than the currently used route when an abnormality of the currently used route is detected in the connection established state. One route is selected, and a route change request is transmitted to the partner system by the route.

The route change response transmitting means 18 receives the route change request from the partner system after transmitting the route change request,
At the time of receiving, based on the information in the storage means, for example, when it is determined that the own system was the called side at the time of establishing the connection, a route change response is transmitted to the partner system.

The route change confirmation receiving means 19 receives the route change confirmation from the partner system after transmitting the route change response,
When the reception route is currently available in the own system, the reception route is determined as a new use route of the connection.

[0024] described later device are all multiple paths between the mating system Ru is implemented in a system that is defined in the network. Next, FIG. 2 shows the first of the present invention .
It is a figure explaining the principle of the path | route change collision control apparatus E and the 2nd path | route change collision control apparatus F of FIG.

The first route change collision control device E includes a storage unit 36 including the following units 36, 37, and 38. When the connection is established with the partner system, the storage unit 36 sends its own system to the calling side. Or, it is stored which one is the called side.

The route change request receiving means 37 is a partner system.
After sending the route change request to the
When the route change request is received, the storage means 36 is provided at the time of the reception.
For example, when it is determined that the own system is the calling side at the time of establishing the connection, the own system is transited to the route change response waiting state based on the stored information of 1.

The route change confirmation transmitting means 38 receives the route change response from the partner system in the route change response waiting state, and transmits the route change confirmation to the partner system in response to the reception.

On the other hand, the second route change collision control device F is
The following means 41, 42, 43 are provided. Storage means 41
Stores whether the own system is a calling side or a called side when a connection is established with the partner system.

The route change response transmitting means 42 is a partner system.
After sending the route change request to the
When a route change request is received, a route change response is sent to the other system based on the information in the storage means at the time of receiving the route change request , for example, when it is determined that the own system was the called side at the time of establishing the connection. Then, the own system is transited to the route change confirmation waiting state.

When the route change confirmation receiving means 43 receives the route change confirmation from the partner system in the waiting state of the route change confirmation, if the reception route is currently available in the own system, the reception route is confirmed. The new use route of the connection is determined.

[0031]

[Action] with reference to FIG. 1, illustrating the use action of the system of the present invention. In the figure, a connection is established between the system C and the system D by, for example, a route.
Was the called party. As a result, the storage means 11 of the system C stores the information indicating the calling side, and the storage means 16 of the system D stores the information indicating the calling side.

In this way, when the system C and the system D independently detect a path abnormality in the state where the connection is established, the system C causes the path change request transmission means 12 to cause the system D to execute the path. The change request transmission means 17 selects a normal route that is currently available in the system independently of each other,
A route change request is transmitted to the partner system via the route.

These route change requests are received by the route change request receiving means 13 in the system C and the route change request receiving means 18 in the system D. The route change request receiving unit 13 of the system C refers to the information stored in the storage unit 11, and if it determines that the own system is the calling side at the time of establishing the connection based on the information, changes the route of the own system. Change to the response waiting state.

On the other hand, the route change request 18 of the system D is also
When it is determined that the own system is the called side at the time of establishing the connection based on the information stored in the storage means 16,
For example, the route change response is transmitted to the system C through the same route as when the route change request is transmitted.

The system C receives the route change response by the route change confirmation transmitting means 14. Then, for example, the reception route is determined as a new use route of the connection.
Store and send a route change confirmation to system D via the use route.

The system D receives the route change confirmation by the route change confirmation receiving means 19, and when the received route is a route which can be currently used in its own system, uses this received route for the new use of the connection. Confirm the route.

In this way, even if a path change request collides with both of the systems C and D to which the connection is established, the connection can be continued by the new path. In the above case, the calling side and the called side at the time of establishing the connection are set to the winner and the loser at the time of the above-mentioned route change request collision, respectively. On the contrary, the winner and the loser are determined. but it may also be so.

Next, the operation of the first route change collision control device E and the second route change collision control device F shown in FIG. 2 will be described. The first route-change collision business device E stores in the storage means 36 whether the own system is the calling side or the called side when the system in which it is installed establishes a connection with the partner system. To do. Similarly, the second route change collision control device F also stores the same information in the storage unit 41 when the connection is established with the partner system.

Hereinafter, description will be made assuming that a connection is established between the systems (system C and system D) in which the above two devices are mounted. In this state, it is assumed that the two systems C and D independently detect an abnormality in the use route of the connection, and a route change request is transmitted from the respective systems C and D to the partner system.

At this time, the route change request receiving means 37 of the first route change collision control device E mounted on the system C side, after transmitting the route change request to the partner system,
When a route change request is received from the partner system, when the connection is established, for example, when it is determined that the own system is the calling side based on the information stored in the storage unit 36 at the time of the reception, the own system is called. Transition to the route change response waiting state.

On the other hand, the second device mounted on the system D side
Route change response transmitting means 42 of the route change collision control device F
After sending the route change request to the partner system,
When a route change request is received from the system, when it is determined that the own system is the called side at the time of establishing the connection, based on the stored information of the storage means 41 at the time of the reception, the other system is notified. It sends a route change response and puts the system into a route change confirmation waiting state.

Subsequently, the first route change collision control device E on the system C side receives the route change response from the partner system in the route change response waiting state, and confirms the route change response to the reception. Send to system.

System D in the route change confirmation waiting state
When receiving the route change confirmation from the partner system, the route change confirmation receiving means 43 of the second route change collision control device F mounted on the above-mentioned reception route if the reception route is currently usable in the own system. To the new use route of the connection.

In this way, by mounting the first and second collision control devices in a system in which a plurality of routes are defined with the partner system in a network environment, route change requests collide. In this case, it becomes possible to continue the connection.

[0045]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows a computer according to an embodiment of the present invention.
It is a block diagram of a network (hereinafter, simply referred to as a network).

In the figure, two systems, system A and system B, are connected to one LAN 100. System A consists of two LAN adapters 111 and 11
Is connected to the LAN 100 via the
LAN via two LAN adapters 121 and 122
It is connected to 100.

Further, the system A has a multiprocessor configuration including two PMs (processor modules) 110-1 and 110-2.
10-2 can communicate with each other. Since the system A has two LAN adapters 111 and 112, the MAC (Medi
a Access Control) address. In addition, the system A distributes the load between the two PMs 110-1 and 110-2 to improve the throughput, so that the local MA
Use C address. This local MAC address is expressed as a mac address. The MAC address assigned to each of the LAN adapters 111 and 112 is generally called a representative MAC address. Here, the MAC addresses assigned to the LAN adapters 111 and 112 are expressed as representative MAC addresses, respectively.

In this case, the LAN adapters 111, 1 are connected to the PM 110-1 which is the master processor.
A representative MAC address is assigned to each of the local mac addresses corresponding to the data transfer path received via 12. On the other hand, LAN adapters 111, 1 are connected to PM 110-2 which is a slave processor.
As each local mac address corresponding to the data transfer path received via 12, a value obtained by adding an integer n to the representative MAC address is assigned.

Note that n is, for example, one of the values 1 to 32, and is updated every time the corresponding LAN adapter 111, 112 is deactivated. On the other hand, the system B also includes two PMs 120-1 and 120-2 that can communicate with each other. And PM120-1 which is a master processor
To LA as two local mac addresses
The representative MAC address assigned to the N adapters 121 and 122 is assigned. On the other hand, as the two local mac addresses assigned to the PM 120-2 that is the slave processor, a value obtained by adding the integer m to the representative MAC address is assigned.

In the network configured as described above, the routes defined between the system A and the system B are: (representative MAC address; representative MAC address): route (representative MAC address; representative MAC address): route (representative MAC address) Address; representative MAC address): route (representative MAC address; representative MAC address): 4 routes represented by a route.

The system A and the system B internally hold the information of the above four paths. Then, for example, when communication is performed between the PM 110-2 of the system A and the PM 120-2 of the system B using the LAN adapter 111 and the LAN adapter 122, the local mac is used.
An address is used, and the above communication is performed via a route'represented by the route information of (representative MAC address + n, representative MAC address + m).

FIG. 4 is a block diagram of a network according to another embodiment of the present invention. In this network,
System A and system B have two LANs 102 and 104
Connected by. That is, system A is LA
It is connected to the LAN 102 via the N adapter 111 and to the LAN 104 via the LAN adapter 112. In addition, the system B is a LAN via the LAN adapter 121.
102 to the LAN 104 via the LAN adapter 122
It is connected to the.

With such a configuration, between system A and system B, (representative MAC address; representative MAC address): route (representative MAC address; representative MAC address): route 2 The route is defined.

Next, the route change process when an abnormality in a path connection has been established in the network configuration shown in FIG. 3 is generated will be described with reference to FIG.

It is assumed that a connection by a route is established between the system A and the system B. In this state, when the system A detects an abnormality in the transmission path of the path, the system A searches for the optimum alternative path based on the held path information. Then, when the route is selected, a route change request is transmitted to the partner system B via the route.

When the system B receives the route change request from the route, it determines whether the route is currently available in its own system . The possible use state, or when the pathway LAN adapter 122 which is used to route after the route change request received is logically deactivated is undefined changes in system B, or a path This is the case, for example, when a new abnormality occurs.

When the system B determines that the route is currently available, it sends a route change response to the system A via the route. The system A checks whether or not the route to which the route change response is transmitted is different from the route to which the route change request is transmitted by itself. in this case,
Since both routes are the same in the route, the route change confirmation is transmitted to the system B via the route.

As a result, system A and system B are
Change the route used from route to route and continue the connection. In this way, when one system (system A in this case) detects an abnormality in the transmission path of the connection-established path, the system on the abnormality detection side selects an alternative path. Then, both systems exchange information (route change request, route change response, route change confirmation) with each other to confirm that the alternative route is currently available in both systems, and Continue the connection between both systems.

On the other hand, when the system B receives the route change request and determines that the alternative route is currently unusable, the system B selects the optimum alternative from the routes other than the route defined in its own system. Select a route.
Then, when the route is selected, the route change response is transmitted to the system A via the route.

Upon receiving the route change response, the system A checks whether or not the received route (route) is different from the route (route) to which the route change request is notified by itself. In this case, since the two routes are different, it is determined whether or not the route requested by the partner system B can be used. The determination of availability in this case is performed in the same manner as when the system A receives the route change request. Then, the system A, the route transmits a path change response via the use if path. As a result, the system A and the system B change the use route from the route to the route and continue the connection.

In this way, if the route proposed by the system (in this case, system A) that has detected the abnormal route is not available in the partner system (in this case, system B), the other partner is detected. The side system can select a new alternative route and continue the connection through the alternative route.

Further, the system A, if the route proposed by the route change response is not currently available due to the internal load of the PM 120-1 or other reasons inside the system, the system A makes the route change response. And an alternative route in which the MAC address of the partner system B is the same as the reception route of. Then, as a result, for example, PM120-
2 can communicate data (representative MAC address: representative M
Select the route'defined by AC address + m). Then, the route change confirmation is transmitted to the system B via the route '. In this case, the route may be selected.

As a result, the system A and the system B change the use route from the route to the route ', and the connection between both systems is continued. In this way, while the system that detected the path abnormality (in this case, system A) selected the alternative route and issued the change request to the alternative route,
When the partner system (in this case, system B) requests another alternative route, the route abnormality detection side system determines that the proposed alternative route is currently unusable in the own system due to a reason within the own system. It is possible to select an alternative route that has the same MAC address of the alternative system and that of the partner system but is different only in its own MAC address, and continue the connection by this alternative route.

Next, a method of detecting a route abnormality and a method of searching for an alternative route when the abnormality is detected or when the LAN adapter is deactivated will be described. 1. Abnormality detection method during data transfer and new route search method at the time of detection 1.1 Data transmission (1) Based on the number of communication routes, the retransmission time, and the maximum number of trials of the system, the route currently in use The maximum number of trials for the route is calculated by the following equation (1).

Nr = (Ns + Rr-1) / Rr (1) Nr: Maximum number of trials for route Ns: Number of remaining trials of system (Ns.max-No) Ns.max: Maximum trial of system Number of times (maximum number of times of transmission for one data) No: Number of trials on another route so far Rr: Number of remaining communication routes of the system +1 Note that Nr is the quotient of the equation (1), and the fractional part is truncated. The initial value of Rr is a value obtained by adding "1" to the number of routes defined between the own system and the other system. (2) When data is sent to the route, if the delivery of the data cannot be confirmed even after the time Tr for confirming the delivery on the route calculated by the following equation (2) has passed, an error will occur in the route. I judge that I did. Then, a route is newly selected, the maximum number of trials for the route is obtained by the above equation (1), and data is transmitted to the route.

Tr = Nr + T1 (2) Tr: time to confirm delivery on the route Nr: maximum number of trials on the route T1: retransmission time The T1 transmits data and then It is the time until the delivery is confirmed, and corresponds to the T1 timer of the OSI transport layer protocol. If the delivery of the data cannot be confirmed even after the retransmission time has elapsed, the data is retransmitted. (3) The procedure of (2) is sequentially tried for all the defined communication paths to find a currently communicable communication path, and the connection is continued by the communication path.

1.2 When Receiving Data (1) When data is received from the partner system via a route different from the route currently in communication, the availability of the route is checked, and if it is available, the partner system uses the route. A route change response is sent to. (2) When data is received from the other system via a route different from the route currently being communicated, the availability of that route is checked, and if it is not available, another route is selected and the other route is selected by this route. Send a route change response to the system. (3) In the route change response of (1) or (2), the maximum number of trials Nr and the retransmission time T1 obtained by the equation (1) are used as in the case of data transmission. If the route confirmation is not transmitted from the partner system even after the delivery confirmation time Tr obtained by the formula (2) has elapsed, it is considered to be abnormal. 2. Method of detecting path abnormality in non-communication state (1) Inactivity monitoring time (t1)
2) The inactivity monitoring remaining time (t3) is divided into two to monitor the inactivity time for the route currently in use.

At the time t1. t2 and t3 are defined as follows. Inactivity monitoring time t1: Data from the other party (OSI transport layer protocol DT-TPDU, AK-TPDU, ED-TPDU)
It is the time to monitor the reception, and corresponds to, for example, the I timer of the OSI protocol. If no data is received from the other party even after this time has elapsed, the connection is disconnected. Inactivity monitoring expiration time t2: time obtained by dividing the inactivity monitoring time t1 in two, which is expressed by the following equation (3). If no data is received from the other party even after this time elapses, it is judged that an abnormality has occurred in that route, the next route is searched, and the non-communication state is monitored for the other system via another route. Data (route change request) to be sent. Remaining time of inactivity monitoring t3: (Inactivity monitoring time t1-Inactivity monitoring expiration time t2 ) , (Maximum number of system attempts Ns.max when rerouting request Ns.max x retransmission time T1 )
But also represented. Inactivity monitoring expiration time t ₂ = Inactivity monitoring time t ₁ − (maximum number of system attempts Ns.max × retransmission time T1) (3) The above I timer will be described in detail. The port entity manages, for each transport connection, an I timer for measuring the elapsed time since the last reception of a TPDU. The transport entity initiates the connection release procedure when this I timer times out. Therefore, when there is no user data to be transferred, the transport entity does not erroneously disconnect the connection by the partner transport entity with which the connection has been established.
-The TPDU must be sent. (2) If the data from the other party cannot be received even after the inactivity monitoring expiration time t2, it is considered that an abnormality has occurred in the route currently in use, and the optimum route is searched from the remaining routes. , And sends a route change request to the partner system via the route.

That is, during the inactivity monitoring remaining time t3, the currently communicable communication path is found by the same procedure as in the case of data transmission described above, and the connection is continued by the communication path. 3. New route search method when LAN adapter is logically deactivated (1) The system defines the route when the LAN adapter for the route to which the connection is currently established is logically deactivated. The optimum route is searched from the remaining routes, and a route change request is transmitted to the partner system via the route. Also when transmitting this route change request, the maximum number of trials Nr is obtained and abnormality in the alternative route is detected, as in the case of data transmission described above. And
If an abnormality is detected, the route change request is sequentially transmitted to the remaining defined routes, the currently communicable route is found, and the connection is continued by the route. The procedure until the connection is continued is the same as the above-described data transmission. 4. Route change method when route change requests from both systems collide 1. ~ 3. With each method, each system detects an abnormality in the route through which the connection is established.
When both systems detect the path abnormality independently of each other almost at the same time, each system transmits a path change request to the other system (hereinafter, referred to as a path change request collision). In this case, for example, a criterion is set such that the calling side system at the time of establishing the connection is the winner of the collision and the called side system is the loser of the collision, and the connection is continued through the route proposed by the calling side system. On the contrary, the calling system is set to the loser of the collision,
The called system may be set as the winner of the collision.

Next, the above 1. ~ 4. A specific example of the above will be described with reference to FIGS. 6 to 12 . In the example described below, CLNP (Connectionless Network Protocol), which is an N (Network) layer protocol of the OSI protocol and provides a connectionless network service, is used. When 1.1.1 Data transmission example, in a network as shown in FIG. 4,
It is assumed that a connection by a route is established between the system A and the system B. At the time of establishing the connection, the system A has “the number of communication paths = 2”, “the maximum number of attempts of the system Ns.max = 5”, and “retransmission time T1 =”.
10 sec ”is stored in the internal memory. Also, using the above formula (1), we obtain 2 times as the maximum number of trials for the route,
Remember this.

In such a state, the system A
The operation when the path abnormality is detected when the data is transmitted to the system B will be described below. The system A transmits the data addressed to the system B to the route (first time).

At this time, in the transport protocol, the above data is DT-TPDU (data transfer-transport protocol data unit: Data Transfer Tr).
asport Protocol Data Unit). Since the system A cannot confirm the transmission data even after the retransmission time T1 elapses, the maximum number of attempts (two times in the above example) and the current number of transmissions (currently one)
And the maximum number of trials for the route has not been reached, data is transmitted again to the route. Since it is not possible to confirm the data even after the retransmission time has passed again, it is detected that the maximum number of transmissions of the route has been reached by comparing with the maximum number of trials (currently 2 times) for the route,
It is considered that an abnormality has occurred in the route. Then, the next route is searched. Then, since there is only one remaining route, the route is selected. The system A newly transmits the data addressed to the system B to the route by DT-TPDU. System B detects that the MAC address sent the data by way of the route rather than by the route. Therefore, the route change response is transmitted to the system A via the route. When the system A receives the route change response for the route, it sends a route change confirmation to the system B,
Establish an alternative route to the route. This allows system A
And the connection between the system B and the system B is continued by the route.

The transmission of the "route change response" from the system B to the system A and the transmission of the "route change confirmation" from the system A to the system B in response thereto are both AK.
-Use TPDU. This AK-TPDU is also the above DT
Like the TPDU, it is one of the transport protocol data units and is used for AK (data acknowledge).

7 (a) and 7 (b) show the format of the header part of this AK-TPDU. The figure (a) is the normal format, and the figure (b) is the extended format. The first byte LI is called a Length Indicator and indicates the byte length excluding the LI of the header parts 200 and 300. The header parts 200 and 300 are divided into fixed parts 210 and 310 and variable parts 220 and 320. Therefore, LI indicates the length from the fixed part 210, 310 to the variable part 220, 320.

[0075] fixing portion 210 and 310, transport protocol data unit code (FIG. 7 (a) "6",
The numbers "60" in FIG. 7 (b)), consists of the parameters of the destination address, sequence number, and CDT (credit value).

The address of the partner system is set in the partner address parameter. The sequence number parameter contains the next DT-TPDU to be received from the partner system.
Sequence number is set.

In the CDT parameter, the number of data that can be continuously received from the sequence number of the next DT-TPDU to be received from the partner system is set. Therefore, the value of (sequence number + credit value) is the upper limit value of the sequence number that can be received.

On the other hand, the variable parts 220 and 320 are8
Check sum parameter 221 (32) shown in (a), (b), and (c)
1), subsequence number parameter 222 (32
2) and FCC parameter 223 (323) etc. are set
To be done.

The checksum parameter 221 (321) is an area for ensuring the validity of the notified data.
The sub sequence number parameter 222 (322) is an arbitrary number (sub sequence number) for each sequence number.
Is set. In this embodiment, this parameter is used by the system to recognize the route change response. That is, each system receives the AK after transmitting the route change request.
-In the sequence number reported by the DPDU,
In the case of the sequence number notified first time, the sub-sequence number is 1 or more, and in the case of the sequence number notified after the second time, the sub-sequence number notified this time is a value that is larger than the previously notified sub-sequence number. When this is recognized as a "route change response". In other words, the system side notifying the "route change response" operates the value set in the subsequence number parameter in the AK-DPDU as described above.

The FCC (Flow Control Confirmation) parameter 223 (323) is used by the system waiting for the notification of the "route change confirmation" to recognize the receipt of the notification. That is, the system in the "route change confirmation" waiting state sets the "sequence number" and "subsequence number" set in the "route change response" transmitted by itself and the FCC parameter of the AK-TPDU received by itself. When the "your sequence number" and the "your subsequence number" are matched, the received AK-TPDU is recognized as "route change confirmation". In other words, the system that returns the "route change confirmation" extracts the "sequence number" and the "sub-sequence number" from the AK-TPDU of the received "route change response", and sends the "sequence change confirmation" by itself. "Your sequence number" and "your subsequence number" of the AK-TPDU for ". 1.
Specific example shown in 2.1 data received at 9 is an example of a case of a network communication path as shown in FIG. 3 is four defined.

In the system A, when the connection is established with the system B by the route, the number of the communication routes of the own system (= 4) is set in the same manner as the data transmission.
Book), the maximum number of trials Ns. max (= 5
Number of times), the number Nr of route trials (= 1 time), and the retransmission time T1 (= 10 sec) are stored internally.

In such a connection established state, the partner system B detects an abnormality in the transmission path of the route or the LAN adapter 12 used in the route.
When the logical deactivation of No. 1 is performed and the "route change request" is transmitted by the DT-TPDU, the following procedure-is performed to continue the connection by the new route. The system A uses the DK-TP transmitted via the route.
DU (route change request) is received. System A is
The status of the route is checked, and if the route is available, the route is selected. If the route is unavailable, the optimal route is selected from the remaining routes. Shall be selected).
The system A obtains 2 times as the maximum number of trials Nr for the route by using the equation (1). Then, the route change response is transmitted to the system B via the route by the AK-TPDU. Since the system A cannot confirm the route change response even after the retransmission time T1 elapses, the system A compares the maximum number of attempts (two times in the above example) with the current number of transmissions (currently one), When it is determined that the maximum number of trials of the route has not been reached, the route change response (AK-TPDU) is transmitted again by the route. Since the system A cannot confirm the route change response even after the retransmission time T1 has passed again, the system A compares the current number of transmissions (2 times) with the maximum number of trials for the route (2 times). Then, when it is determined that the maximum number of transmissions of the route has been reached, the next route is searched. As a result, when the route is selected, the maximum number of trials Nr of the route is obtained by using the above equation (1). System A, in turn, sends a route change response by AK-TPDU to System B over the route. When the system B receives the route change response,
A route change confirmation is sent to the system A by the AK-TPDU via the route. When the system A receives the circuit change confirmation, the system A determines the connection route with the system B as the route. 2.1 Specific example shown at FIG. 10 non-communication state, the system A as shown in FIG. 4 and System B
This is an example in the case of a network having two routes defined between and. When the system A establishes a connection with the system B by a route, the number of communication routes (=) of its own system is set in the same manner as when the data is transmitted.
2), the maximum number of trials (= 5) of the own system, and the retransmission time T1 (= 10 sec) are obtained from the definition information and stored internally.

Further, from the definition information, the inactivity monitoring time t1
(= 300 sec), and after storing this inside,
By (3), the inactivity monitoring expiration time t2 (= 250 sec) is obtained, which is also stored internally. System A is the last data from System B (DT-TPDU or AK-TPDU or ED-TPD
Disconnection monitoring expiration time t2 (= 250 sec after receiving U)
If the next data is not received during), it is determined that an error has occurred in the transmission line of the route, and the optimum route is selected from the remaining defined routes (here, the number of communication routes is Since there are two, select the route). The system A sends a route change request to the system B via the route by using the AK-TPDU. When the system B receives the route change request through the route, the system B transmits a route change response by the AK-TPDU to the system A through the route (in this case, it is assumed that the route was available). Since the system A receives the route change response for the route within the retransmission time T1, the system A transmits a route change confirmation to the system B via the route and determines the route of the new connection as the route. As a result, the connection between the system A and the system B is continued by the route. 3.1 Inactivation of Transmission Line of Route The specific example shown in FIG. 11 also targets the network as shown in FIG. 4 as in the above-mentioned non-communication state. Then, as described above, when the system A establishes a connection with the system B through the route, the number of communication routes of the own system (= 2) and the maximum number of trials of the own system (= 5
Number of times), retransmission time T1 (= 10 sec), inactivity monitoring expiration time (= 250 sec), etc. are stored internally. When the system A recognizes that the transmission path of the currently communicating path is deactivated due to the deactivation of the LAN adapter 111, etc., the system A selects an optimal path from the remaining paths (here,
Since there are two communication routes, the route is selected).

Thereafter, the same procedure as in the non-communication state described above is performed, and the connection between the system A and the system B is continued by the route. Specific example shown in collision 12 4.1 path change request, the route as shown in FIG. 3 is 3
This is an example of a network in which more than one book can be set.

First, it is assumed that the system B makes a call and establishes a connection with the system A through a route. At this time, the systems B and A internally store the fact that they were the calling side and the called side when the connection was established. The system B detects an abnormality in the transmission path of the path currently being communicated and selects the optimum path from the remaining paths (here, the path is selected). Then, the route change request is transmitted to the system A via the route. The system A detects an abnormality in the transmission path of the path currently being communicated, and selects the optimum path from the remaining paths (here, the path is selected). Then, the route change request is transmitted to the system B via the route. System B is
When a route change request sent by system A from another route is received while waiting for a route change response,
The own system judges whether it is the calling side or the called side of the connection. Since the own system is the calling side, it acts as the winner in the collision and waits for a route change response from the partner system A. When the system A receives the route change request transmitted by the system B from another route while waiting for the route change response, the system A determines whether the own system is the caller / callee of the connection, and Since the system is the called side, it operates as a loser at the time of collision and transmits a route change response to the route change request (route) from the partner system B. When the system B receives the route change response (route) from the partner system A while waiting for the route change response, the system B sends a route change confirmation to the partner system A and determines the route of the new connection as the route. As a result, the connection between the system A and the system B is continued by the route.

Next, referring to the flow chart, the operations of the systems A and B which realize the above functions will be described.
This will be described in more detail. a) connection establishment when the processing (initialization processing) First, the system A, B will be described with reference to the flowchart of FIG. 13 the initialization process performed when establishing a connection.

Each system A, B stores, for example, definition value information required at the time of establishing a connection in a predetermined memory when the system is started up. Then, when the connection is established, the initialization process is executed, the definition value information is read, and the processes of steps S1 to S9 shown in the flowchart of FIG. 13 are performed.

That is, first, the maximum number of trials Ns.max of the own system, the number of communication paths of the own system, and the partner system with which the connection is established are provided with this function (functions 1 to 4 described above). Whether or not it is recorded (stored) in an internal memory or the like (not shown). (S1 to S3).

Further, the retransmission time T1 is recorded in the memory, and whether the own system is the calling side or the called side at the time of establishing the connection is also recorded in the memory (S4 to S5).

Furthermore, the route information (partner MAC address, own MAC address) used first for connection is selected and stored (S6). Subsequently, the maximum number of trials Nr for the selected use route is calculated and stored by the equation (1) (S7). Next, the inactivity monitoring time t1 is obtained from the defined value information and stored (S8), and the inactivity monitoring expiration time t2 is calculated and stored by the equation (3) using the time t1 and the like. (S9), the initialization process ends.

Then, after that, the connection is established by a predetermined procedure. b) Processing at the time of data transmission Retransmission of data transmission is permitted only for the maximum number of trials for the currently used route, which is obtained in the initialization processing at the time of connection establishment. Data Transmission Process (First Data Transmission Process) The flowchart of FIG. 14 shows the procedure of the first data transmission process.

First, "1" is set as the number of trials for the route used (S21). Then, the retransmission time T1 is set as the timer value, the data transmission timer is activated (S22), and then the data (DT-TPDU) is transmitted to the partner system via the use route (S23).

In the first data transfer as described above, there is no problem if the reception confirmation (AK-TPDU) of the transmission data can be received from the partner system before the timeout (retransmission time T1 elapses), but if the timeout occurs In order to retransmit the data, the process shifts to the process described below. Data processing (at time-out) The flowchart of FIG. 15 shows the data transmission processing procedure when this time-out occurs.

When a time-out occurs, it is determined whether or not the number of transmissions up to the present for the use route has reached the maximum number of trials for the use route (S31). If not yet reached (S31, NO), the count value of the number of trials for the use route is increased by "1" (S37),
After the retransmission time T1 is set again in the timer value, the data transmission timer is restarted (S38), and the data is transmitted again to the partner system (S39).

On the other hand, when it is determined in step S31 that the maximum number of trials has been reached (S31, YES), the optimum route is selected from the remaining defined routes and stored (S32).

Then, using the above equation (1), the maximum number of trials Nr for this newly selected route is calculated and stored (S3).
3). Then, "0" is set as the number of trials for this newly used route (S34).

Next, referring to the information set in step S3 of the initialization process at the time of establishing the connection,
It is determined whether or not the partner system has this function (a path changing function such as when a path abnormality is detected will be expressed as follows) (S35). When it is determined from the determination that the partner system has this function, the fact that the system is going to enter the route change response waiting state is stored by a predetermined flag or the like (S36).

Then, the processes of steps S37 to S39 are continuously performed, and the data is transmitted to the partner system via the newly selected route. The data in this case is a route change request (see FIG. 6 ) because the transmission route has been changed to the new route.

On the other hand, if the partner system does not have this function of the own system in step S35 (S35, NO), the steps S37 to S are immediately executed.
The processing of 39 is executed.

The process shown in the flowchart of FIG. 15 is repeated until a usable route is found. still,
If there is no remaining route in step S32, the data transmission process is stopped.

As described above, when the partner system also has this function, after transmitting the route change request (step S39), it waits for a response to the request. Then, when the response (route change response) is received from the partner system before the timeout occurs, FIG. 16 explained below.
The process shown in the flowchart of is executed. Route Change Response Reception Processing First, when the route change response is received, the data transmission timer is stopped (S41). Then, the MA of the response
The C address information is checked to determine whether the reception route of the response is different from the communication route of the route change request transmitted by itself (S42).

If both routes are the same, a route change confirmation is transmitted to the partner system through the same communication route as the notice route of the route change response (S46). As a result, the connection is continued by the route proposed by the own system.

On the other hand, if both routes are different in step S42 (S42, YES), it is determined whether or not the route notified by the route change response from the partner system is currently available in the own system (S43). . If it is available (S43, YES), the notified route is stored as a communication route (S45), and a route change confirmation is transmitted to the partner system via the communication route (S46).

Thus, the connection is continued by the route requested by the partner system. Further, if the route notified from the partner system in step S43 is not currently available in the own system, an alternative route whose MAC address on the partner system side is not changed is searched and the alternative route is stored (S44). ). Then, the route change confirmation is transmitted to the partner system via the alternative route (S4).
6).

As a result, the route requested by the partner system and the MAC address on the partner system side are common, but the connection is continued by a route on which the MAC address on the own system side is different.

Next, FIG. 17 to FIG.
This will be described in detail with reference to the flowchart of 19 . Data Reception Process First, the process shown in the flowchart of FIG. 17 will be described.

When the data (DT-TPDU) is received,
The MAC address information is checked to determine whether or not the data reception route is different from the route currently in use (S51).

If both routes are different (S5
1, YES), it is determined that the data is a route change request, and it is checked whether or not the route notified of the request is currently available in the own system (S52). Then, if available, the notified route is stored as a new route (S54), but if not available, an optimal route is selected from the remaining defined routes, and Is stored (S53).

When the processing of either step S52 or S53 is completed, it is next checked whether the partner system has this function based on the internal storage information (S55). Then, if the function is provided (S55, YES), the maximum number of trials Nr for the notification route (hereinafter referred to as the use route) is calculated and stored by the equation (1) (S5).
6).

Then, "1" is set as the number of trials for the use route (S57), the retransmission time T1 is subsequently set in the timer value, and the route change response transmission timer is started (S58).

Next, the fact that the state of waiting for the receipt of the route change confirmation is to be entered is stored in a predetermined flag or the like (S5).
9), A route change response is transmitted to the partner system through the above-mentioned route (S60). Then, after this, the data set in the data portion is extracted from the received data packet (S61).

On the other hand, if the data notification route is the same as the current use route in step S51 (S51, N
O) or if it is found in step S55 that the partner system does not have this function (S55, N
O), the immediately notified data is taken out (S61).

When the route change request is received in this way,
When the partner system has this function, it returns a route change response to the system and waits for a route change confirmation from the partner system to be transmitted. At this time, if the route requested by the partner system is not currently available in the own system, the route change response is transmitted by another alternative route.

[0114] acknowledgment notice to the path change response which is transmitted in step S60 is not come transmitted from the other system, if a timeout occurs, the described below FIG 1
The process shown in the flowchart of FIG. First, it is determined whether or not the number of times the route change response for the use route has been transmitted has reached the maximum number of trials for the use route obtained in step S56 (S71). If not reached (S
71, NO), and "1" is added to the number of trials of the use route (S75). Then, the retransmission time T1 is set in the timer value, the data transmission timer is restarted (S76), and then the route change response is transmitted to the partner system by the use route (S77).

On the other hand, if the number of times the route change response is transmitted to the used circuit has reached the maximum number of trials in step S71 (YES in S71), the optimum route is selected and stored from the remaining defined routes. Yes (S72). Then, the maximum number of trials Nr for the newly selected use route is calculated and stored by the above equation (1) (S73), and "0" is set as the number of trials for the new use route (S73).
74). After that, the processes of steps S75 to S77 described above are performed, and the route change response is retransmitted by the new route.

Thus, a route abnormality can be detected even when the route change response is transmitted, and the route change response can be transmitted to the partner system through a normal route. Then, after transmitting a path change response to the other system in the step S60, the processing at the time of receiving a path change confirmation from the other system before timeout will be described while explaining the flowchart of FIG. 19. Route Change Confirmation Reception Processing First, when the route change confirmation is received, it is determined whether or not the route notified by the route change confirmation is different from the communication route of the route change response transmitted by the local system (S8).
1). If both routes are the same (S81, N
O), stop the route change response transmission timer (S8)
7).

Thus, the connection is continued by the route requested by the own system or the route notified by the partner system in the route change request. On the other hand, if both routes are different in step S81 (S81, YE
S), it is determined whether or not the local MAC addresses are different on the both routes (S82). And the local MAC
If the addresses are different (S82, YES), the received route change confirmation is discarded (S83) and the route change response timer is stopped (S84).

On the other hand, if the local MAC addresses are the same in step S82, it is checked whether the route for which the route change confirmation has been notified is currently usable (S84), and if not (S84, NO). ), Discards the route change confirmation (S85), and stops the route change response timer (S8).
7).

If the notification route is currently available in step S84 (S84, YES), the notification route is stored as the use route (S86), and the route change response transmission timer is stopped (S87). .

As a result, the connection is continued by the route proposed by the partner system (the route which is different from the route notified by the route change response by the local system but has the same MAC address on the local side). d) Path abnormality detection process in non-communication state When the non-communication monitoring expiration timer t2 times out, the process shown in the flowchart of FIG. 20 is performed. Processing at time-out of non-communication monitoring expiration timer 2 When the above-mentioned time-out occurs, it is determined that an abnormality has occurred in the currently used route, and the optimum route is first selected and stored from the remaining defined routes ( S91).

Next, it is checked whether or not the partner system has this function (S92), and if not, a route change request is transmitted through the selected route (S97). On the other hand, if it is determined in step S92 that the partner system has this function (S92, YES), the maximum number of trials Nr for the route (use route) newly selected in step S91 is calculated using the equation (1). It is calculated and stored (S93).

Next, "1" is set as the number of trials for the newly used route (S94), and the fact that the route result response waiting state is to be entered is stored in a predetermined flag (S9).
5). Then, the retransmission time T1 is set to the timer value, the route change request transmission timer is activated (S96), and the route change request is transmitted to the partner system via the above-mentioned used route (S96).
97).

After this, the processing shown in the flow charts of FIGS. 15 and 16 is performed, which is similar to that at the time of data transmission described above. On the other hand, the other party system receives the pathway change request, performs the same process as when the data reception shown in the flowchart of FIGS. 17 to 19 described above.

As a result, the connection is continued in the same manner as the above-mentioned b) when the path abnormality at the time of data transmission is detected. path abnormality detection process when e) LAN adapter is deactivated Next, processing when the LAN adapter in its own system side is logically deactivated will be described with reference to a flowchart of FIG. 21. Processing when the LAN adapter is deactivated When the LAN adapter is deactivated, the optimum route is selected and stored from the remaining defined routes (S101).

Then, it is checked whether or not the partner system has this function (S102). If not, a route change request is immediately transmitted to the partner system through the selected route (S107).

On the other hand, if it is determined in step S101 that the partner system has this function (S101, YE
S), The maximum number of trials Nr for the newly selected route (use route) is calculated and stored using the above equation (1) (S103). Then, "1" is set as the number of trials for the route to be used (S104), and the fact that the system itself is about to transit to the route change response waiting state is stored in a predetermined flag (S105). Then, the retransmission time T is added to the timer value.
Set 1 to start the route change request transmission timer (S
106), and then, a route change request is transmitted to the partner system through the new use route (S107).

[0127] After this, FIG. 15 and FIG. 1 described above
The process shown in the flowchart of 6 is performed. On the other hand, the partner system performs the processing shown in the flowcharts of FIGS. 17 to 19 described above.

As a result, the connection is continued in the same manner as the above-mentioned b) when the path abnormality is detected during data transmission. f) Processing when a route change request collides When a connection is established, both systems detect an abnormality in the transmission path of the route currently used by the connection, and both systems request the other system to change the route. Shall be sent.

In this case, each system executes the process shown in the flow chart of FIG. 20 to select the optimum alternative route in its own system and send the route change request via the route. Therefore, it is possible that the routes selected by both systems do not match. In both systems, after transmitting the route change request, the system waits for a route change response.

[0130] Next, the operation when a path change request received from the remote system when in the該待Chi state will be described with reference to the flowchart of FIG. 22. Processing When Receiving Route Change Request in Route Change Response Waiting State Upon receipt of the route change request, each system determines whether or not the own system was the calling side when the current connection was established (S111). This determination is performed by referring to the recorded information in the initialization processing at the time of connection establishment shown in the flowchart of FIG. 13 described above.

When the own system recognizes that it is the calling side (S111, YES), it extracts data from the received packet (S121). Then, thereafter, the calling side system executes the processing shown in the flowcharts of FIGS. 15 and 16 as in the case of the path abnormality detection at the time of data transmission described above.

On the other hand, when the system recognizes that it is the called side in step S111 (S111, NO), the route to which the route change request is notified is the route in which the system itself has transmitted the route change request to the partner system. It is determined whether or not it is different from the route currently recorded as the use route by the own system (S112). Then, if both routes are the same, the maximum number of trials Nr for the use route is calculated by the above equation (1).
Is calculated and stored (S116). Then, "1" is set as the number of trials for the use route (S11).
7) After setting the retransmission time T1 in the timer value, the route change response transmission timer is started (S118).

Next, the fact that the system itself is about to transit to the route change confirmation waiting state is stored in a predetermined flag (S11).
9), A route change response is transmitted to the partner system via the above-mentioned use route (S120). Then, thereafter, the data is extracted from the received packet (S121).

If it is determined in step S112 that the two routes are different (S112, YES), it is determined whether or not the route to which the route change request from the partner system is notified is currently available in the own system. (S113). If the notification route is available (S113, YE
S), the route notified by the route change request from the partner system is stored as a use route (S115), and thereafter,
The processes of steps S116 to S120 are performed.

Further, if the notification route of the route change request from the partner system is not currently available in the own system in step S113 (S113, NO), the optimum route is selected from the remaining defined routes. Is selected and stored as a use route (S114). Then, after this, the processes of steps S116 to S121 are performed.

As described above, when the own system is the called side at the time of connection, the route notified by the route change request from the calling side partner system is given priority and the route is changed by the route. Send a response. However, if the notification route from the partner system is not currently available in the own system, the optimum route in the own system is selected as the alternative route, and the route change response is transmitted to the partner system by the alternative route. Then, after that, the system waits for a route change confirmation transmitted from the partner system. The subsequent operation on the called system side is the same as the processing shown in the flowcharts of FIGS. 18 and 19 described above.

In this way, when the route change requests collide with each other, the route change request transmitted from the calling side system is prioritized, and is performed in the same manner as in the above b), d) and e). Connection is continued.

Although the example of the network in which the connection is established by the OSI protocol is taken up in the above-mentioned embodiment, the present invention is not limited to this.
It is also applicable to networks in which connections are established by other protocols such as TCP / IP protocol, IPX / SPX protocol, etc.

Further, the two systems are not limited to a network directly connected via a LAN, but may be a wide area network connected via a WAN (wide area network) or internetworking.
It is also applicable to establishing a connection between two systems in other forms of networks such as computer internetworks constructed by.

The system is not limited to the multiprocessor system as described above, but may be a single processor system having a large data transfer amount with a client such as a server machine.

[0141]

As described in detail above, according to the present invention.
Network that defines multiple routes between systems.
Connection between systems in a network environment
When both systems are calling or called
By remembering that, both systems are independent of each other
Detected a path abnormality, and both systems need to change the path respectively.
When a request is sent to the other system and route change requests collide,
Even if the connection is smooth, the route is switched smoothly and the connection is maintained.
Can be made. Also, continue the above connection
Information between both systems (route change request, route change
Select an alternative route while sending and receiving a response, confirmation of route change)
Therefore, there are available routes among the defined routes.
If so, the connection can be continued almost completely. further,
Connection can be continued by the optimal route in each system
It

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention (No. 1).

FIG. 2 is a diagram for explaining the principle of the present invention (No. 2).

FIG. 3 shows a network configuration according to an embodiment of the present invention .
It is a figure.

FIG. 4 shows a network configuration of another embodiment of the present invention .
It is a figure.

5 is a connection establishment status in the network shown in FIG .
Connection when a route error occurs in the state
It is a figure explaining a method.

FIG. 6 is a route for data transmission in the network shown in FIG .
An example of how to continue the connection when an error is detected
It is a figure explaining.

[Fig. 7] Used for notification of route change response and route change confirmation
FIG. 6 is a diagram illustrating a format of an AK-TPDU that is stored.
It

FIG. 8 shows various parameters set in a variable part of AK-TPDU .
It is a figure explaining a meter.

FIG. 9 is a diagram showing a route change request data in the network shown in FIG .
An example of how to continue the connection when receiving data
FIG.

10 is an inactive state in the network shown in FIG .
How to continue the connection when the dynamic monitoring expiration time is exceeded
It is a figure explaining an example of a method.

FIG. 11 is a diagram showing one system in the network shown in FIG .
When the transmission path of the connection use path is deactivated
It is a figure explaining an example of the connection continuation method.

FIG. 12: Connection when route change requests collide
It is a figure explaining an example of the continuation method of.

FIG. 13 illustrates an initialization process when establishing a connection .
It is a flowchart.

FIG. 14 is a flowchart illustrating a first data transmission process.
It is a chart.

FIG. 15 illustrates data transmission processing when a timeout occurs
It is a flowchart to do.

FIG. 16: Reception process of route change response during data transmission
It is a flow chart explaining a reason.

FIG. 17 is a flowchart explaining the operation when receiving data .
It is

FIG. 18 shows a time-out in the waiting state for the route change response .
This is an explanation for the operation when a failure occurs.

FIG. 19 illustrates an operation when a route change confirmation is received.
2 is a flow chart.

FIG. 20 shows the action when a path abnormality is detected in a non-communication state .
It is a flow chart explaining a work.

[Fig. 21] When the transmission path is deactivated in the own system
It is a flowchart explaining the process to perform.

FIG. 22: Route change while waiting for route change response
In the flowchart explaining the operation when receiving a request
is there.

FIG. 23 is a diagram illustrating a conventional problem.

[Description of Reference Signs ] 12, 17 Route change request transmitting means 14, 38 Route change confirmation transmitting means 13, 37 Route change request receiving means 18, 42 Route change response transmitting means 19, 43 Route change confirmation receiving means 11, 16, 36 , 41 storage means

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-2-98257 (JP, A) JP-A 5-227213 (JP, A) JP-A 62-159942 (JP, A) JP-A 61- 100037 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12/28-12/46 H04L 1/22 H04L 12/56

Claims (8)

(57) [Claims] 1. A partner system in a network
In a system where multiple routes are defined between and, when a connection is established with the other system,
Indicate whether your system is the calling side or the called side
Memorize the memory and the memory currently used when the connection is established.
When an abnormality of the route is detected,
Select one route from the remaining defined routes
Then, a route change request is sent to the other system via the route.
A route change request transmitting unit that receives the route change request, and a route change request from the partner system after the route change request is transmitted.
At the time of reception, and based on the stored information of the storage means,
Route change that transits the system to the route change response wait state
Request receiving means and the route from the partner system in the route change response waiting state
Receiving a change response and confirming the route change in response to the reception
Equipped with a path change confirmation transmitting means for transmitting to the system
A system characterized by that. 2. The route change request receiving means is the storage device.
When the connection is established, the system
System is the calling party, the system
The system according to claim 1, wherein the system is transited to a route change response waiting state . 3. A partner system within a network
In a system where multiple routes are defined between, when a connection is established with the other system,
Indicate whether your system is the calling side or the called side
Memorize the memory and the memory currently used when the connection is established.
When an abnormality of the route is detected,
Select one route from the remaining defined routes
Then, a route change request is sent to the other system via the route.
A path change request transmission means signals to, said path after the change request transmission, the path change request from the other system
Is received, and at the time of receiving, based on the stored information in the storage means,
Send route change response to hand system Route change response
Confirm the route change from the partner system after transmitting the route change response with the transmitting means.
Received, and the reception route is now available in the local system
When the connection is
And a route change confirmation receiving means for determining a proper use route . 4. The route change response transmitting means is the storage device.
When the connection is established, the system
If it is determined that the system was the called party,
4. The system according to claim 3 , wherein a route change response is transmitted to the system. 5. A partner system within a network
A device implemented in a system in which multiple routes are defined between
When a connection is established with the other system,
Indicate whether your system is the calling side or the called side
After sending the route change request to the storage means to remember and the partner system,
When a route change request is received from the
Based on the memory information stored in the memory, the local system waits for a route change response.
Route change request receiving means for transitioning to the active state and the route from the partner system in the route change response waiting state.
Receiving a change response and confirming the route change in response to the reception
A route change collision control device comprising: a route change confirmation transmission means for transmitting to a system. 6. The route change request transmitting means is the storage.
When the connection is established, the system
System is the calling party, the system
6. The route change collision control device according to claim 5 , further comprising:
Place 7. A partner system within a network
A device implemented in a system in which multiple routes are defined between
When a connection is established with the other system,
The local system was calling or serial which one of the called party
After sending the route change request to the storage means to remember and the partner system,
When a route change request is received from the
Route change response to the partner system based on the information in the memory
Is sent to switch the system to the route change confirmation waiting state.
The route change response transmission means to be activated, and the other system in the route change confirmation waiting state.
The route change confirmation is received, and the reception route is currently in the system.
The reception path is connected to the connection when it is available.
Route change confirmation receiving means to confirm the new usage route
And a route changing collision control device. 8. The route change response transmission means stores the storage.
When the connection is established, the system
If it is determined that the system was the called party,
The route change collision control device according to claim 7 , wherein a route change response is transmitted to the system.
Place