JP3356220B2 - Connection setting status management 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 connection setting status management system for managing a connection setting status in an ATM network.

[0002]

2. Description of the Related Art In an ATM network, a connection is set between terminating devices by setting a connection identifier for each link constituting a connection. When transferring data through the set connection, the terminating device sends out a cell including a header storing a connection identifier for identifying the connection to which the terminal belongs as a communication unit.

[0003] Each relay device has a connection identifier conversion table. The connection identifier conversion table describes the correspondence between the connection identifier on the input link and the connection identifier on the output link. Each relay device rewrites the connection identifier of the cell based on the correspondence described in the connection identifier conversion table, and transfers the cell with the rewritten connection identifier, thereby realizing cell transfer to the terminal device on the receiving side. I do.

In some cases, each relay device in the ATM network needs to know the setting status of the identifier of a connection accommodated in a transmission path between the relay device and an adjacent relay device. For example, when a certain relay device detects a transmission line failure, it sends a failure recovery message to each transmission line to which the relay device is connected, and propagates the failure recovery message to each relay device in the system. In this example, a case where each of the relay devices in the network searches for a detour in an autonomous distributed manner and switches the connection will be described as an example. In such a case, if the failure recovery message is sent to all the relay devices adjacent to the relay device, the number of messages flowing in the system increases dramatically because the failure recovery message is sequentially relayed. In some cases.

[0005] However, such a problem can be avoided by transmitting a failure recovery message only to the adjacent relay device that can effectively execute the detour search.
Such an adjacent relay device is, for example, an adjacent relay device having a lot of vacant connections in a transmission path between the relay device and a relay device that is to send a failure recovery message. On the other hand, the connection setting status with the adjacent relay device can be grasped by knowing the setting status of the connection identifier conversion table of the adjacent relay device.

Conventionally, a relay device accesses a node management center installed in a system when it is desired to know the setting status of a connection accommodated in a transmission path between the relay device and an adjacent relay device. The node management center has a centralized database, and the centralized database has data for setting / releasing each connection.

[0007] Therefore, when the relay apparatus wants to know the connection setting status, it issues an inquiry to the centralized database of the node management center. Then, by receiving the status regarding the connection included in the response from the node management center, the information regarding the status of setting the connection with the adjacent relay device is obtained.

[0008]

Since the relay device in the conventional ATM network obtains the connection setting status information as described above, a line for accessing a centralized database is required. Further, depending on the relationship between the data correction timing and the readout timing in the centralized database, the data in the centralized database may not match the actual situation. Therefore, there is a problem that it is difficult to accurately grasp the connection setting status with the adjacent relay device at a certain point in time for all connections.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a connection setting status in which each relay device can accurately and quickly grasp a connection setting status with an adjacent relay device. The purpose is to provide a management system.

[0010]

According to a first aspect of the present invention, there is provided a connection setting status management system, comprising:
Creating a management cell that recognizes the connection identifier setting status from the connection identifier conversion table, creates a connection identifier setting status management cell including the connection identifier setting status information, and periodically transfers it to all adjacent relay devices. And an identifier setting status monitor for monitoring the connection identifier setting status information included in the received connection identifier setting status management cell.

According to a second aspect of the present invention, in the connection setting status management system according to the first aspect of the present invention, the management cell creating unit transmits the connection identifier setting status management cell transmission cell. The configuration is such that a connection identifier setting status management cell is inserted into a band reserved for use or into an empty cell having no information cell.

According to a third aspect of the present invention, there is provided a connection setting status management system, wherein the management cell creating unit includes:
When the connection identifier setting status information is transferred by a plurality of connection identifier setting status management cells, a sequence number indicating a cell order and a tail flag indicating whether or not the cell is the tail cell are added to each connection status management cell. In this configuration, the identifier setting status monitor unit recognizes one piece of connection identifier setting status information from the sequence number and the last flag in the received connection identifier setting status management cell.

[0013]

In the connection setting status management system according to the present invention, the connection identifier setting status management cell including the setting status of the connection identifier for the outgoing transmission line of each relay device is periodically transmitted to the adjacent relay device. Will be transferred. Each relay device autonomously and decentralized ascertains the connection setting status with the adjacent relay device by monitoring the content of the transferred connection identifier setting status management cell as needed.

[0014]

FIG. 1 is a block diagram showing an example of an ATM network to which a connection setting status management system according to a first embodiment of the present invention is applied. In this connection setting status management system, the relay device 1 is connected to the relay devices 2 to 7 via transmission lines 82 to 87, respectively. Each of the relay devices 2 to 7 is connected to another relay device or a terminal device. In FIG. 1, each of the transmission paths 82 to 8
FIG. 7 shows a state in which three connections are set. Normally, each of the relay devices 1 to 7 relays information cells.

In the repeater 1, the incoming transmission line interfaces 101 to 103 receive cells from the respective repeaters 2 to 4. Connection identifier conversion unit 12
1 to 123 are connection identifier conversion tables 131
The connection identifier of the received cell is converted according to the contents of .about.132.

The space switch 14 sends the cells to the transmission lines 85 to 87 according to the connection path.
Switching cells. Egress transmission line interface 1
Numerals 11 to 113 are for transmitting cells output from the space switch 14 to the corresponding transmission lines 85 to 87.

The management cell creation unit 15 creates a connection identifier setting status management cell and sends it to each of the adjacent relay devices.
Is for inputting a connection identifier setting status management cell as needed to know the identifier setting status.

FIG. 1 shows an interface for accommodating transmission lines 82 to 84 between the relay devices 2 to 4 as an input-side transmission line interface, and a relay device 5 to 7 as an output-side transmission line interface. A transmission line that accommodates the transmission lines 85 to 87 to the relay devices 2 to 4 is shown. There is also an incoming transmission line interface to accommodate. Further, the relay devices 2 to 7 are also the relay device 1
This is the same configuration as.

Next, the operation will be described. For example, when an information cell arrives at the relay device 1 from the transmission line 82, the cell is input to the connection identifier conversion unit 121 via the incoming transmission line interface 101. In that cell,
The connection identifier set by the relay device 2 is included. This connection identifier corresponds to the connection identifier of the transmission line 82 of the connection from the relay device 2 to the relay device 1 for transferring the cell.

In the connection identifier conversion table 131, the connection identifier and the connection identifier set for the outgoing link from the relay device 1 to the adjacent relay device in the connection for transferring the cell are set. The connection identifier conversion unit 121 rewrites the connection identifier of the cell to a connection identifier corresponding to the outgoing link.

Then, the space switch 14 outputs the cell whose connection identifier has been rewritten to the outgoing transmission line interface corresponding to the transmission line on the connection path. For example, if it is the egress transmission line interface 111
Then, the cell is transferred to the relay device 5 via the transmission line 85. Next, the connection identifier setting status management cell transmission process will be described. In addition, ATM
In a network, a virtual path (VP; Vi
rtual Path) connection and virtual channel (V
C; Virtual Channel) connection, and this connection setting status management system is applicable to any of them. Hereinafter, a case of a VP connection will be described as an example.

In each of the relay devices 1 to 7, the management cell creation unit 15 periodically creates a connection identifier setting status management cell with reference to the contents of the connection identifier conversion tables 131 to 133 of its own device. To all the adjacent relay devices. For example, the management cell creator 15 of the relay device 1 sends the information to the relay devices 2 to 7.

The connection identifier setting status management cell has, for example, a configuration as shown in FIG. That is, it includes a header 210 and a payload 220. The header 210 includes a virtual channel identifier (VCI; Virt).
ual Channel Identifier) 211, Virtual Path Identifier (VPI) 212, Payload Type Identifier (PTI)
r) An area 214 in which 213 and other header components are set. The management cell creation unit 15
211, OAM (Operation, Administration and Man
agement) Set a value indicating that this is a cell. Also,
A specific VPI identifier value is set in the VPI 212.

The payload 220 has an OAM type 221
And connection setting status information 222
And a connection setting status field in which is set. The management cell creation unit 15 converts the OAM type 221 into
A value indicating that the cell is a connection identifier setting status management cell is set.

The connection setting status information 222 includes a relay device number, each outgoing transmission line interface number,
In addition, each connection identifier set in the outgoing transmission line interface is set.

When a time corresponding to a predetermined period elapses, the management cell creation unit 15 creates a connection identifier setting status management cell as follows. That is, the connection identifier set for the outgoing transmission line interface 111 is extracted from the contents of the connection identifier conversion tables 131 to 133. As described above, each of the connection identifier conversion tables 131 to 133
, A connection identifier of a cell received by a certain connection and a connection identifier corresponding to a transmission path to which the cell is to be output are set in association with each other. Therefore, the connection identifier set for the outgoing line interface 111 can be extracted. Other outgoing line interface 112,1
The same processing is performed for the block 13.

The connection identifier set for each of the outgoing transmission line interfaces 111 to 113 by the above processing is the same as that of the outgoing transmission line interface 111 to 113.
13 is obtained. The management cell creation unit 15 of the relay device 1 creates a connection identifier setting status management cell in which each acquired connection identifier is set in the connection setting status field.

The management cell creating unit 15 of the relay device 1 transfers the connection identifier setting status management cell to the relay devices 5 to 7 via the transmission lines 85 to 87 on the outgoing side. Also,
Although not shown in FIG. 1, the connection identifier setting status management cell is also transferred to the relay devices 2 to 4 via the corresponding outgoing transmission line. Also, the other relay devices 2 to 7,
In each case, the connection identifier setting status management cell in which the connection identifier corresponding to the output side transmission line interface in the own device is set is transferred to the adjacent relay device.

In each of the relay devices 1 to 7, the identifier setting status monitor 16 checks the VC of the header 210 of the received cell.
IAM contents and OAM type 22 of payload 220
Check the contents of 1. As a result of the confirmation, knowing that the cell is a connection identifier setting status management cell,
The connection setting status information 222 set in the connection identifier setting status management cell is recognized. Further, it may be held. In addition, each relay device 1
Upon receiving the connection identifier setting status management cell, the identifier setting status monitor unit 16 terminates the cell. That is, the cell is not relayed.

By the above operation, each of the relay devices 1 to 7
Can recognize each connection identifier set for each outgoing transmission line interface in the adjacent relay device. That is, the number of connections set on the transmission path between the own device and the adjacent relay device can be recognized.

Here, a case has been described in which connection identifier setting status management cells in which connection identifiers are set for all outgoing transmission line interfaces of the own device are transferred to each adjacent relay device. , Different connection identifier setting status management cells may be transferred. That is, an operation of creating a connection identifier setting status management cell in which only each connection identifier for one outgoing transmission line interface is set and transmitting the cell only to the transmission line accommodated by the outgoing transmission line interface. Is performed for all outgoing transmission line interfaces. By doing so, the amount of information carried in each connection identifier setting status management cell is reduced.

In the case of a VC connection, the management cell creation unit 15 specifies a specific VCI 211 in the VCI 211 of the header 210.
A CI value is set, and a value indicating an OAM cell is set in the PTI 213. Also, the same information as in the case of the VP connection is set in the connection setting status information 222.

Each of the relay devices 1 to 7 confirms the PTI 213 of the header 210 of the received cell and the OAM type 221 of the payload 220. As a result of the confirmation, if it is found that the cell is a connection identifier setting status management cell, it recognizes the connection identifier setting status information included in the connection identifier setting status management cell. As described above, in the case of the VC connection, similarly to the case of the VP connection, the relay devices 1 to 7 can grasp the current setting status of the connection.

FIG. 3 is a schematic diagram showing a connection identifier setting status management cell transmission band in the connection setting status management system according to the second embodiment of the present invention. FIG. 3 shows a band 811 for a connection identifier setting status management cell in a transmission line band 810 of the transmission line 80.
Is secured separately from the band 812 for the information cell. Note that this band division is set in advance at the time of design.

The configuration of this connection setting status management system is substantially the same as that shown in FIG. 1. In this case, however, the management cell creating unit 15 uses a connection identifier setting status management cell which is set in advance. A connection identifier setting status management cell is transmitted using the band 811 for the connection. In addition, as shown in FIG.
11 and 312, and finds the empty cell sections 311 and 31
2, a connection identifier setting status management cell may be inserted. As described above, the quality degradation of the information cell due to the competition between the connection identifier setting status management cell and the information cell is prevented.

FIG. 5 is an explanatory diagram showing the format of the connection identifier setting status management cell in the connection setting status management system according to the third embodiment of the present invention. In this case, a region in which a sequence number 224 indicating the order and a tail flag 225 indicating the last cell are set is added to the payload 220. The configuration of this connection setting status management system is as follows:
Although the functions are slightly different, they are the same as those shown in FIG.

When the connection identifier setting status information does not fit in one connection identifier setting status management cell, the management cell generator 15 divides the connection identifier setting status information into a plurality of connection identifier setting status management cells and divides the connection identifier setting status information into a plurality of connection identifier setting status management cells. Then, the blocks composed of the connection identifier setting status management cells are transferred to the transmission lines 85 to 87 on the outgoing side. Also, the management cell creation unit 15
Sets the sequence number 224 of each connection identifier setting status management cell to a number indicating the number of the cell, and makes the last flag 225 of the last connection identifier setting status management cell significant. deep.

Each of the relay devices 1 to 7 recognizes each connection identifier setting status management cell constituting one block from the received connection identifier setting status management cell sequence number 224 and the last flag 225, and One connection identifier setting status information is obtained from the connection identifier setting status management cell. Other processes are the same as those in the first embodiment.

Thereafter, for example, when the relay apparatus 1 detects a failure in a certain transmission line, compared with the conventional system,
The detour can be set without increasing the failure recovery message in the system. That is, since the relay device 1 knows the setting status of the connection accommodated in the transmission path between the relay device and the adjacent relay device, the relay device 1 targets the adjacent relay device having a small number of connections using the transmission line therewith. As a failure recovery message. Further, the relay device that has received the failure recovery message can also transfer the failure recovery message to an adjacent relay device having a small number of connections using a transmission path there between.

That is, a failure recovery message is not sent to an unused connection identifier having a small number of connection identifiers, and a message transfer to an adjacent relay device which is considered not to contribute to efficient recovery is excluded. In this way, it is possible to reduce the processing associated with the failure recovery in each relay device in the system. In particular, the effect is great when many connections having a small capacity are accommodated in a failed transmission line.

Further, if the capacity information of each connection is added to the connection identifier setting status information, each relay device can grasp the free capacity of each transmission path in real time. Therefore, by using the capacity information together, it is possible to further limit the transfer destination of the failure recovery message. Therefore, when the capacity information is added, the processing associated with the failure recovery in each relay device is further reduced.

[0042]

As described above, according to the first aspect of the present invention, the connection setting status management system allows the relay device to send the connection identifier setting status management cell including the connection identifier setting status information to the adjacent relay device. In addition to forwarding, it is configured to monitor the connection identifier setting status information included in the received connection identifier setting status management cell, so that each relay device can grasp the accurate connection setting status in real time, What can perform processing efficiently can be provided.

When the relay apparatus inserts the connection identifier setting status management cell into a band reserved for transmitting the connection identifier setting status management cell or into an empty cell where no information cell exists. In addition to the effects of the first aspect of the present invention, there is also an effect that it is possible to provide a system in which information cells are not degraded by the connection identifier setting status management cell.

Then, the relay apparatus sets a sequence number indicating the order of the cells and a last flag indicating whether or not the cell is the last cell in each connection identifier setting status management cell. When the configuration is such that the attribute information of the connection is recognized from the sequence number and the tail flag in the cell, in addition to the effect of the invention of claim 1, furthermore,
When the amount of the connection identifier setting status information is too large to transfer in one cell, the setting status information can be accurately grasped with a short response time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a connection setting status management system according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a connection identifier setting status management cell.

FIG. 3 is a schematic diagram illustrating a connection identifier setting status management cell transmission band according to a second embodiment;

FIG. 4 is an explanatory diagram showing how a connection identifier setting status management cell is inserted into an empty cell.

FIG. 5 is an explanatory diagram showing a configuration of a connection identifier setting status management cell in a third embodiment.

[Explanation of symbols]

 1-7 relay device 101-103 incoming transmission line interface 111-113 outgoing transmission line interface 121-123 connection identifier conversion unit 131-133 connection identifier conversion table 14 space switch 15 management cell creation unit 16 identifier setting status monitor unit

Continuation of the front page (56) References JP-A-2-44833 (JP, A) JP-A-3-286645 (JP, A) JP-A-62-219846 (JP, A) JP-A-63-82143 (JP) JP-A-6-14057 (JP, A) JP-A-61-212943 (JP, A) JP-A-5-191408 (JP, A) JP-A-1-204541 (JP, A) 4-70034 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/56

Claims (3)

(57) [Claims] 1. A plurality of terminating devices and a plurality of relay devices are connected via a transmission path, and a connection is set between the terminating devices. Each relay device has a connection identifier in a receiving cell and a connection identifier in an outgoing link. In an ATM network that relays cells using a connection identifier conversion table in which a correspondence relationship with
In a connection state management system that manages a connection setting state, the relay device recognizes a connection identifier setting state from the connection identifier conversion table, and creates a connection identifier setting state management cell including connection identifier setting state information. A management cell creating unit for periodically transferring the connection identifier setting information to all adjacent relay devices, and an identifier setting status monitoring unit for monitoring connection identifier setting status information included in the received connection identifier setting status management cell. A connection setting status management system, comprising: 2. The management cell creation unit inserts the connection identifier setting status management cell into a band reserved for transmitting the connection identifier setting status management cell or into an empty cell having no information cell. The connection setting status management system according to claim 1, wherein 3. When the connection identifier setting status information is transferred by a plurality of connection identifier setting status management cells, the management cell creation unit indicates a sequence number indicating a cell order and whether or not the cell is the last cell. The last flag is set in each connection identifier setting status management cell, and the identifier setting status monitor recognizes the connection identifier setting status information from the sequence number and the last flag in the received connection identifier setting status management cell. The connection setting status management system according to claim 1.