JP5588837B2 - Transmission equipment - Google Patents

Description

  The present invention relates to management of route information in packet transport technology.

  In recent years, broadband lines such as the Internet have become widespread, and the demand for lines has been increasing mainly for IP traffic, and the services accommodated therein are also diversifying rapidly. Under these circumstances, the cross-connect method for layer 1 transmission equipment has shifted from the conventional “circuit switching type” represented by SDH to the “packet switching type” that is highly compatible with IP networks such as routers. Has been.

  As a typical packet-switched cross-connect method, there is MPLS (Multi Protocol Label Switch) (for example, Non-Patent Document 1). In MPLS, generally, a route is determined by an algorithm, and nodes connected in accordance with the route are communicated to determine a label. Each node has a table indicating correspondence between input labels and output ports as route information, and data is transferred to an output port designated based on the table. The route management of a packet transmission network represented by MPLS is based on distributed management in which a forwarding destination is determined for each node based on a policy such as network resources and the number of hops.

  In such a packet transmission network, transmission is performed in packet units without securing a fixed time slot. On the other hand, there is a merit that traffic can be accommodated efficiently, but the route selection algorithm determines the route autonomously for each device, so in the event of a failure, it is difficult to specify the failure location and spillover range. And management issues.

  In response to these problems, standardization of a technique called MPLS-TP (Multi Protocol Label Switch Transport Profile) is currently being promoted in IETF (for example, Non-Patent Document 2). This MPLS-TP is a technology that combines the reliability and maintenance operability of legacy legacy lines such as SDH, while taking the form of packet transmission with MPLS as the transmission method. MPLS-TP adopts the concept of “expansion of OAM (Operation And Maintenance) function” and “explicit route management” over conventional MPLS.

  “OAM function” is a general term for various maintenance operation functions to support high-quality and stable transfer of transferred data. “Failure detection function”, “Failure point identification function”, “Failure notification function” ”,“ Performance monitoring function ”, and“ Protection function ”. In order to realize these functions, standardization of OAM-dedicated packets is being promoted separately from packets for transferring services (for example, Non-Patent Document 3).

  “Explicit route management function” is not an autonomous distributed route determination method that was mainstream in the conventional packet transmission network, but the maintainer specifies the start point, end point, and passage point as the route through which traffic passes. The route can be set statically. The route once specified is not automatically updated due to a factor other than the setting instruction from the maintenance person. As a result, the maintenance person can clearly grasp where the service line is actually transmitted.

  Furthermore, MPLS-TP follows that of MPLS as a transmission method. By using the MPLS label, multi-protocol accommodation possibility that accommodates user signals regardless of the accommodation signal type, and QoS control, it is possible to clearly separate service classes between user signals. By combining these with circuit emulation technology, the rapidly increasing IP traffic and traditional SDH lines such as SDH are accommodated on the same platform, and the layer 1 and layer 2 networks are integrated and managed.

IETF RFC3031 "Multiprotocol Label Switching Architecture" IETF RFC5654 "Requirements of an MPLS Transport Profile" IETF RFC5860 "Requirements for Operations, Administration, and Maintenance (OAM) in MPLS Transport Networks"

  When accommodating legacy lines such as conventional SDH in packet transmission methods such as conventional Ethernet (registered trademark) and MPLS, database backup and recovery become a further issue. In order to apply the packet transmission method to SDH network substitution and legacy line accommodation, high reliability and fault tolerance comparable to SDH network substitution and legacy line are required.

  The route management in the SDH transmission network manages a “physical connection” through which data communicates. Therefore, it is possible to explicitly grasp the route where the traffic is transmitted. This route information is set for each transmission device under supervisory control from the network management device by explicitly specifying the start point, the passing point, and the end point by the maintenance person. The transmission apparatus 100 includes an IF unit 103 that performs transmission / reception processing and termination processing of main signals, a cross-connect unit 104 that performs connection processing of each signal, and a device monitoring control unit 102 that monitors and controls them. The path information set in each transmission device 100 is information including an input port to which the signal is input and an output port to which the signal is output. Each transmission apparatus sets the set route information in the hardware that performs the main signal processing, and writes and holds it in the nonvolatile memory as a backup of the route information in case of a failure. A basic configuration example is shown in FIG. The route information related to the route set by the higher-level network management device 101 is transferred to the in-device DB management unit 1022 via the external access IF 1021 provided in the device monitoring control unit 102 of the transmission device. Then, the in-device DB management unit 102 sends out route information via the communication control unit 1023 included in the device monitoring control unit 102, and the subordinate IF unit 103, the communication control unit 1031 of the cross-connect unit 104, hardware access The route information is transmitted to the route information setting memory 1033 via the control unit 1032 to set the route. Further, the in-device DB management unit 1022 in the device monitoring control unit 102 transfers the newly set path information to the backup memory 1024, and updates the backup data held therein to the latest state.

  The backup data of the path information held in the backup memory 1024 is sent to the main signal system hardware 103 and 104 when the power supplied to the transmission apparatus is cut off and then recovered. Set and used for automatic service recovery.

  Figure 2 shows an overview of the recovery sequence when the power supplied to the transmission device is cut off and then recovered. When the power supplied to the transmission device is cut off, power is not supplied to the IF unit and the cross-connect unit that perform main signal processing, and the service that passes through them is stopped. Thereafter, when the power supply to the transmission apparatus is restored, the route information set in the IF unit 204 and the cross-connect unit 205 is cleared in the initial state. For this reason, since it is necessary to reset the route information in order to restore the service via the route, a route information transfer request 2001 is transmitted to the in-device DB management unit 202. The in-device DB management unit 202 that has received the path information transfer request 2001 transmits a backup data request 2002 to the backup memory 201 and acquires the backup data 2003 from the backup memory 201. The in-device DB management unit 202 transmits the path information 2004 to the hardware access control unit 203 based on the acquired backup data 2003. The hardware access control unit 203 generates IF unit setting data 2005 and cross-connect setting data 2006 based on the received route information 2004, and sends the IF unit route information setting memory 204 and the cross-connect unit route information setting memory 205 respectively. To set. As described above, when the IF unit path information setting memory 204 and the cross-connect unit path information setting memory 205 are cleared, the setting is performed based on the backup data 2003 stored in the backup memory 201, and the service line Is restored.

  Furthermore, the transmission device accommodating legacy lines such as SDH reads out the route information set in the route information setting memory of the IF unit or the cross-connect unit for the route information to be stored in this backup memory, and the route information Must be rebuilt and written to backup memory as backup data. For example, when a device monitoring control unit fails and the device monitoring control unit package is replaced, no path information is stored in the backup memory of the new replaced device monitoring control unit. Therefore, the setting information written in the path information setting memory of the IF unit or cross-connect unit is read, the path information of the path that is accommodated is reconstructed based on the read setting information, and written to the backup memory. A function to perform is necessary.

  Outline of the sequence for restoring backup data from the setting data stored in the path information setting memory of the IF section and cross-connect section when the package of the device monitoring control section is replaced and there is no path information data in the backup memory It is shown in FIG.

  When the path information stored in the memory does not exist, the backup memory 301 transmits a path information transfer request 3001 to the IF unit path information setting memory 304 and the cross-connect unit path information setting memory 305. The IF unit path information setting memory 304 that has received it transmits the IF unit setting data 3003 set to itself to the hardware access control unit 303, and the cross-connect unit path information setting memory 305 is set to itself. The cross-connect unit setting data 3002 is transmitted to the hardware access control unit 303. The hardware access control unit 303 generates path information 3004 from the IF unit setting data 3003 and the cross-connect unit setting data 3002, and transmits the path information 3004 to the in-device DB management unit 302. The in-device DB management unit 302 writes backup data of path information to the backup memory and stores it.

  As described above, when the backup memory 301 is cleared due to the replacement of the package of the in-device monitoring control unit, the setting data stored in the IF unit path information setting memory 304 or the cross-connect unit path information setting memory 305 Based on the above, the backup data in the backup memory 301 is restored.

  A transmission apparatus that accommodates legacy lines such as SDH has a redundant configuration regarding setting information between the path information setting memory provided in the IF section and the cross-connect section and the backup memory provided in the apparatus monitoring control section. Even if one of the data is cleared for some reason, it has a function of recovering based on the data stored in the other.

  Such a function requires data communication between the path information setting memory and the backup memory. In the case of an SDH transmission network, physical connection information is set as it is in the path information setting memory, so that “path information” and “setting information” are both based on physical information and the contents match.

  On the other hand, in the case of a packet transmission network, physical “route information” is not uniquely derived from “setting information”. Since logical connection management is performed in which data and the route through which data passes are associated with a specific ID (for example, MAC address or MPLS label), the setting value in the route information setting memory itself is an explicit route. Does not show information.

  For example, FIG. 4 shows a specific setting example of the route information associated with the MPLS label in the route information setting memory. The setting of routing information in MPLS basically includes three elements of “input label 401”, “output label 402”, and “output port 403”. On the other hand, the physical route information usually indicates a physical connection state, and explicitly indicates an “input port” to which the signal is input and an “output port” to which the signal is output. The configuration is such that the input port is physically selected as the output signal on the port side. As an example here, the “input port” and “output port” are cross-connected in units of signals received at the port, but the unit of cross-connect does not have to be per port, for example, smaller time slot units It doesn't matter. However, the setting information in MPLS only defines the output port of data corresponding to the input label, and there is no information corresponding to “input port”. Therefore, it is not possible to determine the physical connection state such as which input port and which output port are connected only from these information, and it is set in the path information setting memory provided in the IF part and cross-connect part. There is a problem that physical route information cannot be obtained from the set information. For this reason, in the packet transmission network, when there is no route information data in the backup memory, there is a problem that the recovery using the route information setting memory provided in the IF unit and the cross-connect unit illustrated in FIG. 3 cannot be performed. is there.

  In addition to the path information necessary for data transfer, a memory capable of storing physical connection information is provided in the transmission apparatus. When restoring the backup data stored in the backup memory of the transmission apparatus, the setting information necessary for data transfer and the information related to the physical connection state are determined from the path information data and physical information data set in the memory. And restore.

As an example, the transmission apparatus according to the present invention is a transmission apparatus that includes a control unit that communicates with an external management device, and an interface unit and a cross-connect unit that receive information from the control unit. Route information for data transfer received from the management device
A communication control unit that transmits to the interface unit and the cross-connect unit , input port information that is information of an input port for inputting data, which is transmitted to the interface unit and the cross-connect unit and received from the external management device ; has a first memory for storing the route information and the input port information for the data transfer, and a management unit for exchanging routing information and the input port information for the data transfer between the first memory, The interface unit and the cross-connect unit generate logical connection data based on the path information for data transfer transmitted to the control unit, and transmit the data transmitted to the control unit. a conversion unit that generates a physical connection of data based on the route information and the input port information, before And a second memory for storing data for a logical connection, at least one of said interface unit and the cross-connect unit is characterized in that it has a third memory for storing data of the physical connection.

  Here, the first memory is configured to store the logical connection read from the second memory and the third memory when the management unit transmits a path information transfer request to the second memory and the third memory. Data and data of the physical connection may be stored.

  In the packet transmission network, it is possible to reliably realize a database recovery function related to route information.

2 shows a configuration example of a network management device and a transmission device under its monitoring control. An example of a recovery sequence in a case where recovery is performed after the power supplied to the transmission apparatus is cut off. Example of recovery sequence when backup memory is cleared. A specific example of setting route information associated with an MPLS label in a route information setting memory. Configuration in the first embodiment. 6 is a setting example of route information setting of each transmission device by the network management device having the configuration of FIG. 6 is an example of a backup data recovery sequence according to the first embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 5 is a configuration diagram in the first embodiment. The transmission apparatus according to the present embodiment includes a node A 502, a node B 503, a node C 504, and a node D 505, which are transmission apparatuses 501 that perform packet switching using MPLS-TP connected in a ring shape, and network management that monitors and controls them. It is comprised with the apparatus 506. Here, the protocol of the ring network, that is, the data transfer method of the cross-connect unit to be described later is MPLS-TP, but the specification of the present embodiment can be applied to other packet switching protocols.

  The network management device 506 is connected to each node through a general public network 507 such as a DCN (Data Communication Network) line provided by a communication carrier, and remotely monitors and controls each node. In the configuration shown in the figure, the node B 503, the node C 504, and the node D 505 are not physically directly connected to the general public network 507, but each node has a communication function capable of communicating with each other. The network management device 506 can be monitored and controlled via the communication function. For example, the node C 504 can be monitored and controlled by a route of “network management apparatus 506-general public network 507-node A 502-node B 503-node C 504”. For simplicity, such communication routes are not shown in the figure, but all nodes can be monitored and controlled by the network management apparatus via the general public network. The network management device 506 may be directly connected to each node without going through the general public network 507. A network other than the general public network 507 may be interposed between the network management device 506 and each node.

  The transmission device 501 includes a device monitoring control unit (control unit) 508, an IF (interface) unit 509, and a cross-connect unit 519. The device monitoring control unit 508 manages an external access IF 510 that exchanges monitoring control commands 5001 with the network management device 506, and a database in the device that stores path information, and exchanges backup data with a backup memory (memory). In-device DB management unit (management unit) 511, backup memory 518 for storing backup data related to route information, subordinate package IF unit 509, cross-connect unit 519, route information (setting) 5002, route information (read) The communication control unit 512 is a communication interface for exchanging 5003.

  The IF unit 509 accommodates an electrical signal or an optical signal that is a signal from the client device. The cross-connect unit 519 connects the signals accommodated in the IF unit to each other, has a plurality of ports, and can output a packet input from an arbitrary port to an arbitrary port in units of packets. The IF unit 509 and the cross-connect unit 519 include a path information setting memory 516 that receives path information and stores the path information, and a physical information setting memory 517. A hardware access control unit 515 that performs data write control and data read control, a communication control unit 513 that is a communication interface for exchanging path information (setting) 5002 and path information (read) 5003 with the in-device monitoring control unit 508, Consists of. In the transmission device, the communication control unit 512 in the device monitoring control unit and the communication control unit 513 in the IF unit and the cross-connect unit are connected to each other via an internal transmission line with an interface. And communicate with each other via the interface. The IF unit 509 and the cross-connect unit 519 have the same configuration related to setting route information. Therefore, for the sake of simplicity, the description below will focus on the processing in the IF unit 509, but the same applies to the cross-connect unit 519 in relation to setting the route information.

  In the configuration shown in Fig. 5, the maintenance person starts from "" Node B IF-B1 port b1 (P5001) "" and "" Node B IF-B2 port b2 (P5002) "-" Node C IF-C1 port c1 ( P5003) ”-” Node C IF-C2 Port c2 (P5004) ”-“ Node D IF-D1 Port d1 (P5005) ”” passed through, “Node D IF-D2 Port d2 (P5006)” ” A case where the Ethernet path 520 is set will be described. At this time, the network management device 506 transmits the route information as shown in FIG. 6 to the node B 503, the node C 504, and the node D 505 through which the path passes, and sets each route information setting memory. Do. That is, it transmits to each node as route information including information specifying an input label, an output label, and an output port. This is information lacking input port information as physical information. Among them, the input label 601 and output label 602 are the same labels used in MPLS defined in IETF RFC3032, and are identifiers consisting of 20 bits that are used as a reference for label switching. is there. These are setting values necessary for data transfer by MPLS-TP. The network management apparatus 506 automatically determines that the values match between adjacent nodes, and the node B 503 is used as a monitoring control command 5001. Then, the data is transmitted to the in-device DB management unit 511 via the external access IF 510 of the node C 504 and the node D 505. Further, since the network management apparatus recognizes the “input port” through which the path passes in the node, this “input port” information is also used as the monitoring control command 5001 and combined with the node B 503, node C 504, and node D 505. To the in-device DB management unit 511 via the external access IF 510. The in-device DB management unit 511 transmits path information (setting) 5002 including the input label 601, the output label 602, the input port 603, and the output port 604 to the logical-physical information conversion unit 514. The logical-physical information conversion unit 514 generates logical setting data 5004 including input label information 601, output label information 602, and output port information 604 necessary for data transfer by MPLS-TP, and transmits the logical setting data 5004 to the hardware access control unit 515. Thus, the setting is made in the path information setting memory 516, and the physical setting data 5005 including the input port information and the output port information is generated and transmitted to the hardware access control unit 515 to be set in the physical information storage memory 517. Here, the logical setting data 5004 is setting data indicating a logical connection necessary for MPLS-TP data transfer, and the physical setting data 5005 indicates an explicit physical connection including an input port and an output port. It is setting data.

  A sequence diagram of FIG. 7 shows a method of restoring the path information stored in the backup memory when the path information having the contents shown in FIG. 6 is set in the configuration of FIG. In this case, it is assumed that there is no path-related data in the backup memory, such as when the device management control unit package is replaced.

  The backup memory 701 transmits a path information transfer request 7001 to the path information setting memory 705 and the physical information setting memory 706 when there is no path information to be stored in the memory. The path information setting memory 705 that has received it transmits the logical setting data 7002 set in the corresponding section to the logical-physical information conversion section 703, and the physical information setting memory 706 receives the physical setting set in the corresponding section. Data 7003 is transmitted to the logical-physical information conversion unit 703. The logical-physical information conversion unit 703 includes logical setting data 7002 and physical setting data 7003, physical connection information including information from input ports and output ports, and logical connection information including information on input labels and output labels. Route information 7004 is generated and transmitted to the in-device DB management unit 702. The in-device DB management unit 702 writes and stores the received path information in the backup memory.

  In this figure, the input label and output label are automatically determined and assigned by the network management device. However, the maintenance person may set and assign the input label and output label of each node individually. I do not care.

  As described above, the input port setting is not necessary for data transfer by MPLS-TP. However, in the transmission apparatus according to the present embodiment, information specifying the input label, output label, and output port is transmitted as route information from the network management apparatus to the transmission apparatus (node) group through which the path should pass. An input port that is not directly used for data transfer by MPLS-TP is set in the apparatus, and is stored in a physical information setting memory in the transmission apparatus. As a result, at the time of recovery when the backup memory is cleared, logical connection information consisting of the input label and output label is obtained from the path information setting memory, and from the input port and output port from the physical information setting memory. Thus, it is possible to reliably restore information to be stored in the backup memory.

  In FIG. 5, both the IF unit and the cross-connect unit include a path information setting memory and a physical information setting memory. The path information setting memory is provided in each package in order to store information necessary for the main signal to be conducted. However, the physical information setting memory may be installed only in either the IF unit or the cross-connect unit. Furthermore, it may be installed as another configuration in the transmission apparatus instead of either the IF unit or the cross-connect unit. The physical information setting memory stores auxiliary information for restoring path information, and the physical mounting position is not limited. Therefore, the arrangement may be determined in consideration of component cost, package mounting space, and the like. When the physical information setting memory is mounted at a plurality of locations, it can be restored from the stored information of the physical information setting memory mounted in another package.

101 Network management device 102 Device monitoring control unit 103 IF unit 104 Cross-connect unit 1021 External access IF
1022 In-device DB management unit 1023 Communication control unit 1024 Backup memory 1031 Communication control unit 1032 Hardware access control unit 1033 Path information setting memory 201 Backup memory 202 In-device DB management unit 203 Hardware access control unit 204 IF unit path information setting memory 205 Cross-connect unit path information setting memory 2001 Path information transfer request 2002 Backup data request 2003 Backup data 2004 Path information 2005 IF unit setting data 2006 Cross-connect unit setting data 301 Backup memory 302 In-device DB management unit 303 Hardware access control unit 304 IF unit route information setting memory 305 Cross-connect unit route information setting memory 3001 Route information transfer request 3002 Cross-connect unit setting data 3003 IF unit Constant Data 3004 path information 3005 the backup data 3006 the backup data writing 401 input label 402 output label 403 output port 501 transmitting apparatus 502 Node A
503 Node B
504 Node C
505 Node D
506 Network management device 507 General public network 508 Device monitoring control unit 509 IF unit 510 External access IF
511 Device DB management unit 512 Communication control unit 513 Communication control unit 514 Logical-physical information conversion unit 515 Hardware access control unit 516 Path information setting memory 517 Physical information setting memory 518 Backup memory 519 Cross-connect unit 520 Path 5001 Monitoring control command 5002 Route information (setting)
5003 Route information (read)
5004 Logical setting data 5005 Physical setting data 5006 Physical read data 5007 Logical read data 5008 Backup data 5009 Backup read data P5001 to 5006 Port 601 of each node through which the path passes Input label 602 Output label 603 Input port 604 Output port 701 Backup memory 702 In-device DB management unit 703 Logical-physical information conversion unit 704 Hardware access control unit 705 Path information setting memory 706 Physical information setting memory 7001 Path information transfer request 7002 Logical setting data 7003 Physical setting data 7004 Path information 7005 Backup data 7006 Backup data writing

Claims (7)

A transmission device comprising a control unit that communicates with an external management device, an interface unit that receives information from the control unit, and a cross-connect unit,
The controller is
Input port information, which is information of an input port for inputting data, which is received from the external management device, is transmitted to the interface unit and the cross-connect unit, and is received from the external management device. Communication control unit for transmitting to the interface unit and the cross-connect unit ,
A first memory storing path information for the data transfer and the input port information ;
The first memory and the management unit for exchanging the path information for the data transfer and the input port information ,
The interface unit and the cross-connect unit are
Based on the path information for data transfer transmitted to the control unit, logical connection data is generated, and based on the path information for data transfer and input port information transmitted to the control unit. A conversion unit for generating physical connection data;
A second memory for storing data of the logical connection;
At least one of the interface unit and the cross-connect unit is
A transmission apparatus comprising a third memory for storing data of the physical connection. The data of the logical connection includes input label information, output label information, and output port information for the data transfer,
The transmission apparatus according to claim 1, wherein the data of the physical connection includes input port information and output port information for the data transfer.   The transmission apparatus according to claim 1, wherein the path information for data transfer includes information specifying an input label, an output label, and an output port.   The transmission apparatus according to claim 1, wherein the cross-connect unit includes a plurality of ports.   The first memory includes data of the logical connection read from the second memory and the third memory when the management unit transmits a path information transfer request to the second memory and the third memory, and The transmission apparatus according to claim 1, wherein physical transmission data is stored. When the management unit transmits a path information transfer request to the second memory and the third memory, the conversion unit reads the logical connection data read from the second memory and the third memory, and the physical Generate route information from the connection data and send it to the management unit,
The transmission apparatus according to claim 1, wherein the management unit stores the route information in the first memory when receiving the route information from the conversion unit.   The transmission apparatus according to claim 1, wherein the cross-connect unit performs data transfer by MPLS-TP.

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