JP3379715B2 - Connection 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 status management system for managing connection status in an ATM network.

[0002]

2. Description of the Related Art A relay device in an ATM network has a working connection, which is a connection in which a route is set and is currently in operation, and a capacity which is reserved for backup and in which a route is set but valid information cells are not transferred. It may be necessary to know the state of the backup connection, which is the 0 connection.

For this purpose, a node management center is installed. The node management center has a centralized database, and the attribute information of each connection is stored in the centralized database. The connection attribute information of the centralized database is written or modified based on the data when setting and releasing the connection.

The relay device issues an inquiry to the centralized database of the node management center when it wants to grasp the attribute information of the connection accommodated in the relay device. Then, the connection attribute information is obtained by receiving the connection attribute information included in the response from the node management center.

[0005]

Since the relay device in the conventional ATM network obtains the connection attribute information as described above, a line for centralized database access is required. In addition, even if an inquiry is made to the centralized database, no response is immediately obtained, and there is a problem that the response time becomes long, especially when access from a plurality of relay devices competes.

Further, depending on the relationship between the data correction timing and the data reading 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 grasp accurate attribute information at a certain time for all connections.

The present invention has been made in order to solve such a problem, and a relay device is capable of accurately grasping the state of the current connection accommodated in the relay device in a short time. The purpose is to provide a state management system.

[0008]

A connection state management system according to the invention described in claim 1 creates a connection state management cell containing connection attribute information in a terminating device and transfers it to a connection path. A state management cell processing unit that stores the received connection state management cell in the relay device and also transfers the received connection state management cell to the connection path It is equipped with.

A connection state management system according to a second aspect of the present invention is the connection state management system according to the first aspect of the invention, in which the state management cell creation unit of the terminating device and the state management cell processing unit of the relay device are The connection state management cell is configured to be inserted into the band reserved for transmitting the connection state management cell between the terminating devices of the respective connections, or to the empty cell having no information cell.

In the connection state management system according to the third aspect of the present invention, a connection state management cell including connection attribute information and error detection / correction code is created in the terminating device and transferred to the connection path. When the relay device confirms that the connection attribute information of the received connection state management cell is normal by the error detection / correction code, it provides the received connection attribute information to the relay device. Holds the connection status management cell in the connection status management cell when the received connection status management cell is transferred to the connection path and it is detected that the received connection attribute information is incorrect. And the transfer of the connection state management cell is stopped, and Those having a status management cell processing unit that performs an abnormality notification to the device.

A connection state management system according to a fourth aspect of the present invention is the connection state management system according to the first or third aspect of the invention, in which the state management cell creation unit of the terminal device manages a plurality of connection states. When the connection attribute information is transferred by the use cell, the sequence number indicating the cell order and the end flag indicating whether it is the end cell are set in each connection state management cell, and the relay device state management is performed. The cell processing unit is configured to recognize connection attribute information from the received sequence number and sequence number in the connection state management cell.

A connection state management system according to a fifth aspect of the present invention is the connection state management system according to the fourth aspect, wherein the state management cell processing unit of the relay device receives the sequence in the connection state management cell. When detecting discontinuity of numbers, and when a timeout occurs before receiving a connection state management cell whose last flag is significant, hold connection attribute information and connection state in the connection state management cell The configuration is such that the transfer of the management cell is stopped.

[0013]

In the connection state management system according to the present invention, the attribute information of the connection is transferred from the terminating device on the transmitting side to the terminating device on the receiving side through the relay device for the working connection and the backup connection for which the routes are set. . The relay device can copy the attribute information of the connection in its own device if necessary,
It is possible to obtain current information on connection attributes in a distributed and real-time manner.

[0014]

1 is a block diagram showing an example of an ATM network to which a connection state management system according to a first embodiment of the present invention is applied. In this connection state management system, the terminating devices 1 and 3 send and receive information cells, and send out the connection state management cells created by the state management cell creation units 11 and 31 based on the data in the databases 41 and 42. It is a thing. In the terminating devices 1 and 3, the terminating units 12 and 32 terminate the connection state management cell. The relay device 2 has a transmission line 5
It relays cells flowing through the connection 61 set up between 1, 52 and stores the connection state management cell in the storage unit (not shown) of the state management cell processing unit 21.

Next, the operation will be described. Here, a case where the terminating device 1 sends out a connection state management cell will be described. Further, in the ATM network, a virtual path (VP) connection and a virtual channel (VC) are used as connections.
There is a connection, but this connection state management system is applicable to both. Below, V
The case of P connection will be described as an example.

In the terminating device 1, the state management cell creating section 11 has a cycle set for the connection 61,
A connection state management cell in which the VP connection attribute information is set is created based on the data of the database 41 in which the connection attribute information is stored. The connection attribute information is written or modified in the database 41 when the connection is set or released.

The connection state management cell is, for example,
The configuration is as shown in FIG. That is, the header 110 and the payload 120 are included. The header 110 is
Virtual channel identifier (VCI)
111, virtual path identifier (VPI; VP Identifie)
r) 112, payload type identifier (PTI; Payloa)
d Type Identifier) 113 and an area 114 in which other header components are set. The state management cell creation unit 11 adds the OAM (Operation, Admi
nistration and Management) Set the value to indicate the cell. Further, the same VPI value as that set in the information cell is set in the VPI 112.

The payload 120 is an OAM type 121
And a connection attribute information field in which the connection attribute information 122 is set.
The state management cell creation unit 11 sets a value indicating the connection state management cell in the OAM type 121.

Further, as the information set in the connection attribute information 122, the terminating device ID as route information,
Via relay device ID and VPI value used for each link,
A connection capacity parameter as capacity information, a connection ID as other attributes, an identifier indicating a public network connection or a dedicated line connection, an identifier indicating a working connection or a spare connection, and a connection failure history are set. To be done.

The terminating device 1 sends the connection state management cell to the relay device 2 on the path of the connection 61. In the relay device 2, the state management cell processing unit 21
When a cell is received, VCI1 of the header 110 of the cell
Check the contents of 11 and the contents of the OAM type 121 of the payload 120. As a result of the confirmation, when the cell is found to be the connection state management cell, the connection state management cell is copied to the storage unit.

Then, the state management cell processing unit 21 transfers the cell to the next relay device (not shown). The next relay device performs the same process as the process in the relay device 2.
Then, until the cell reaches the terminating device 3 on the receiving side, the same process as the process in the relay device 2 is sequentially executed in each relay device. The connection state management cell is terminated by the termination unit 32 of the termination device 3 on the receiving side.

By referring to the connection state management cell in the state management cell processing unit 21, each relay device can grasp the current attribute information of the connection accommodated in its own device. That is, the relay device can autonomously and dispersively grasp the current attribute information of the accommodated connections.

In the case of VC connection, the terminating device 1
Sets the same VCI value as the value set in the information cell in the VCI 111 of the header 110, and sets the value indicating the OAM cell in the PTI 113. Further, the same information as in the case of the VP connection is set in the connection attribute information 122. However, as one piece of route information, the used VCI value for each link is set instead of the used VPI value for each link.

The state management cell processing unit 21 of each relay device
The PTI 113 of the header 110 of the received cell and the OAM type 121 of the payload 120 are confirmed. As a result of the confirmation, when the cell is found to be the connection state management cell, the connection state management cell is copied. As described above, even in the case of VC connection,
As in the case of the VP connection, the relay device can grasp the current attribute information of the accommodated connection.

FIG. 3 is a schematic diagram showing a connection state management cell transmission band in the connection state management system according to the second embodiment of the present invention. In FIG. 3, in the transmission path band 500 of the transmission path 50, the bands 521, 522, 523 for the connection state management cells are secured separately from the bands 511, 512, 513 for the information cells. It is shown. The band division is preset at the time of design.

The configuration of this connection status management system is almost the same as that shown in FIG. 1, but in this case,
State management cell creation unit 11 of termination device 1 and relay device 2
The state management cell processing unit 21 of FIG.
A connection state management cell is sent to 22, 523. In addition, as shown in FIG. 4, empty cell sections 311 and 3
12 may be searched, and the connection state management cell may be inserted into the empty cell sections 311 and 312.
As described above, the quality deterioration of the information cell due to the competition between the connection state management cell and the information cell is prevented.

When a bit error occurs in the transmission line 61, the status management cell processing unit 21 of the relay device 2 may copy an incorrect connection status management cell. FIG. 5 is a block diagram showing an example of an ATM network to which a connection state management system according to a third embodiment of the present invention which can prevent such a situation is applied. FIG. 6 is an explanatory diagram showing the format of a connection state management cell in this connection state management system. As shown in FIG. 5, in this case, the relay device 2 is provided with a state management cell processing unit 22 which disassembles the received connection state management cell and also detects an error in the information in the payload 120. .

Therefore, in the connection state management cell in this case, as shown in FIG.
An error detection / error correction code 123 for enabling error detection and error correction of the payload part is set.

Next, the operation will be described. The operation of the terminating device 1 is the same as that of the first embodiment except that the state management cell creation unit 11 also sets the error detection / error correction code 123. When receiving the cell, the state management cell processing unit 22 in the relay device 2 receives the header 110 of the cell.
VCI 111 and payload 120 OAM type 12
Check 1 and. As a result of the confirmation, when it is known that the cell is a connection state management cell, the connection state management cell is disassembled and the information in the payload 120 is detected by the error detection / error correction code 123 in the connection state management cell. Perform error detection.

If there is no error, the connection attribute information in the payload 120 is copied to the storage unit. Then, the connection state management cell is transferred to the next relay device (not shown). When an error is detected, if the error can be corrected, the error is corrected, the connection attribute information is copied to the storage unit, and the corrected connection state management cell is transferred to the next relay device.

If correction is not possible, the state management cell processing unit 22 does not copy the connection attribute information,
Also, the connection state management cell is terminated. That is, the relay device 2 does not transfer the connection state management cell so that the downstream relay device does not perform unnecessary processing. Then, the relay device 2 waits for the next connection state management cell.

As described above, it is possible to prevent erroneous connection attribute information from being monitored while maintaining the effect of the connection state management system according to the first embodiment.

In the case of the VC connection, the relay device 2 uses the PTI 113 of the header 110 of the received cell.
And confirming from the OAM type 121 of the payload 120 that it is a connection state management cell,
This is similar to the case of the first embodiment. That is, this embodiment is also applicable to the case of VC connection.

FIG. 6 is an explanatory diagram showing the format of a connection state management cell in the connection state management system according to the fourth embodiment of the present invention. In this case, the payload 120 has a sequence number 1 indicating the order.
24 and the last flag 12 indicating the last cell
An area where 5 is set is added. The configuration of this connection status management system is the same as that shown in FIG. 1 or FIG. 5, although the function is slightly different.

When the connection attribute information cannot fit in one connection state management cell, the terminating device 1
The state management cell creation unit 11 sets the connection attribute information for each of the plurality of connection state management cells, and transfers the block including the connection state management cells to the transmission path 51. The state management cell creation unit 11 uses the sequence number 124 of each connection state management cell.
Is set to the number indicating the number of the cell, and the last flag 1 of the last connection state management cell is set.
Keep 25 significant.

The state management cell processing unit 21 (or the state management cell processing unit 22) of the relay device 2 uses the sequence number 124 of the received connection state management cell and the last flag 125 to make each connection that constitutes one block. Recognize the state management cells and copy the connection attribute information from these connection state management cells. Other processes are the same as in the case of the first embodiment or the third embodiment.

A block in which a certain connection state management cell is missing may be received by the relay device 2 due to a buffer overflow or erroneous routing in the relay device on the way. The state management cell processing unit 21 (or the state management cell processing unit 22) of the relay device 2 detects that the content of the sequence number 124 of the received connection state management cell is discontinuous, and thus the connection state management cell Know the loss of a cell.

In such a case, a series of connection state management cells may be prevented from being copied, and a block of connection state management cells in the next cycle may be waited. In that case, the state management cell processing unit 21 (or the state management cell processing unit 22) of the relay device 2 notifies that the termination device 1 on the transmission side has an abnormality. Then, when some connection state management cells constituting a certain block have already been received when the discontinuity of the sequence number 124 is detected, those connection state management cells are terminated.

The state management cell processing unit 2 of the relay device 2
1 (or the state management cell processing unit 22) has a time-out function, and when a series of connection state management cells is not received within a specified time, it is determined that an abnormality has occurred and the above processing is executed. May be. That is, the state management cell processing unit 21 (or the state management cell processing unit 22)
When the first connection state management cell is received and the connection state management cell in which the last flag 125 is significant is not received within the specified time,
Judge that an abnormality has occurred. It is also possible to detect the deterioration of connection quality by notifying the termination device 1 of the abnormality. That is, information for identifying the quality deterioration section can be provided to the terminal device 1.

[0040]

As described above, according to the first aspect of the invention, in the connection state management system, the terminating device sends the connection state management cell containing the attribute information of the connection, and the relay device receives it. Since the configuration is such that the attribute information of the connection in the connection status management cell is retained and the received connection status management cell is transferred to the connection path, the relay device will be able to send the current connection of the active connection and the backup connection as needed. It is possible to accurately grasp the state management in and with a short response time. Therefore, there is an effect that the usage status of the connection terminated by each terminating device can be grasped and that the network management capability is improved. That is, it is possible to accurately and promptly respond to the inquiry from the network administrator.

In the case where the terminating device and the relay device are configured to insert the connection state management cell into a band reserved for transmitting the connection state management cell or into an empty cell in which no information cell exists, In addition to the effect of the invention according to claim 1, there is also an effect that a system in which an information cell is not deteriorated by the connection state management cell can be provided.

In the case where the terminating device is configured to send out a connection state management cell containing an error detection / correction code and the relay device executes error detection / correction of the received connection state management cell, In addition to the effect of the invention described in Item 1, there is also an effect that it is possible to effectively prevent handling of incorrect connection attribute information due to a bit error.

A sequence in the connection state management cell received by the relay device is set in each connection state management cell by setting the sequence number indicating the cell order of the terminating device and the last flag indicating whether it is the last cell. When the connection attribute information is recognized from the number and the last flag, in addition to the effect according to the invention of claim 1, the connection attribute information has a large amount of information in one cell. Even when transfer is not possible, there is an effect that the current state management of the working connection and the protection connection can be grasped accurately and with a short response time.

When the relay device detects the discontinuity of the sequence numbers in the received connection state management cells, or when a timeout occurs before receiving the connection state management cell whose tail flag is significant,
If it is configured to execute a predetermined error processing,
In addition to the effect of the first aspect of the invention, there is also an effect that the terminal device can be provided with information for identifying the quality deterioration section with respect to connection quality deterioration.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a configuration of a connection state management cell.

FIG. 3 is a schematic diagram showing a connection state management cell transmission band in a second embodiment of the present invention.

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

FIG. 5 is a block diagram showing a connection state management system according to a third exemplary embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a configuration of a connection state management cell according to the third embodiment of the present invention.

FIG. 7 is an explanatory diagram showing the configuration of a connection state management cell according to the fourth embodiment of the present invention.

[Explanation of symbols]

1,3 Terminator 2 relay devices 11,31 State management cell creation unit 12,32 Terminal part 21 State management cell processing unit 22 State management cell processing unit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-114911 (JP, A) JP-A-3-139043 (JP, A) JP-A-5-268257 (JP, A) JP-A-5- 252190 (JP, A) JP-A-6-326728 (JP, A) JP-A-6-69923 (JP, A) JP-A-2-44833 (JP, A) JP-A-5-268242 (JP, A) Japanese Patent Publication 7-87459 (JP, B2) Patent 2585843 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12/56

Claims (5)

(57) [Claims] 1. A terminal device and a relay device are connected via a transmission line, and a connection is established between the terminal devices.
In a connection state management system for managing a connection state in a TM network, the terminator creates a connection state management cell containing connection attribute information and transfers it to a connection path. The relay device holds the attribute information of the connection in the received connection state management cell, and further comprises a state management cell processing unit for transferring the received connection state management cell to the connection path. A characteristic connection status management system. 2. A state management cell creation unit of a terminating device and a state management cell processing unit of a relay device connect to a band reserved for transmitting a connection state management cell or to an empty cell in which no information cell exists. The connection status management system according to claim 1, wherein a status management cell is inserted. 3. A terminal device and a relay device are connected via a transmission line, and a connection is established between the terminal devices.
In a connection state management system for managing a connection state in a TM network, the terminating device creates a connection state management cell including connection attribute information and error detection / correction code and transfers it to a connection path. When the relay device confirms that the connection attribute information of the received connection state management cell is normal by an error detection / correction code, the relay device for receiving the connection state management When the attribute information of the connection in the cell is retained, the received connection state management cell is transferred to the connection route, and it is detected that the connection attribute information of the received connection state management cell is incorrect. , Connection in the connection state management cell With stop transfer of the holding and connection state management cell attribute information, the connection state management system comprising the state managing cell processing unit that performs an abnormality notification to the relay device on the transmission side. 4. The state management cell creation unit of the terminating device, when transferring the connection attribute information by a plurality of connection state management cells, indicates the sequence number indicating the order of cells and whether or not it is the last cell. A tail flag is set in each connection status management cell, and a status management cell processing unit of the relay device recognizes connection attribute information from the sequence number and the tail flag in the received connection status management cell. The connection state management system according to claim 1 or claim 3. 5. The state management cell processing unit of the relay device detects the sequence number discontinuity in the received connection state management cell, or before receiving the connection state management cell having a significant last flag. 5. The connection status according to claim 4, wherein when a timeout occurs in the connection status management cell, the retention of the attribute information of the connection in the connection status management cell and the transfer of the connection status management cell are stopped and the relay device on the transmission side is notified of the abnormality. Management system.