JP2013005028A - Oam packet conversion method and oam packet conversion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the conventional problem in which path monitoring is unavailable where devices employing different OAM schemes are connected.SOLUTION: The OAM packet conversion method is used for a network which includes a first device and a second device employing different MPLS-TP OAM schemes. The method converts a format of a Y.1731-based OAM packet received from the first device to a format of a BFD-based OAM packet by mapping an MPLS-TP label header comprising an LSP label, a GAL label, a TC, and TTL, an OpCode, and an information field of the relevant OAM type of the Y.1731-based packet to an MPLS-TP label header comprising an LSP label, a GAL label, a TC, and TTL, a Channel Type, and an information field of the relevant OAM type of the BFD-based packet respectively, and transfers the converted packet to the second device.

Description

  The present invention relates to an OAM packet transmission technique.

  In recent years, MPLS-TP (Multi Protocol Label Switching-Transport Profile) has attracted attention as a connection-oriented transmission technique that provides communication services with transmission quality equivalent to ATM and SDH. In MPLS-TP, maintenance operation management equivalent to that of a synchronous network is possible by constructing a virtual path in an IP network or the like and realizing an OAM (Operation Maintenance, and Management) function (for example, see Non-Patent Document 1). ).

  MPLS-TP performs path monitoring by exchanging control packets (MPLS-TP OAM packets) between devices on a label switched path (LSP). As the MPLS-TP OAM function, for example, CC / CV, RDI, AIS, LM, DM, CSF, and the like have been proposed (for example, see Non-Patent Document 2).

  Although MPLS-TP is being standardized by organizations such as IETF and ITU-T, the base technology of MPLS-TP OAM is different. Two systems have been proposed: a 1731-based OAM (for example, see Non-Patent Document 3) and a BFD-based OAM (for example, see Non-Patent Document 4 to Non-Patent Document 7).

RFC 5921 (draft-ietf-mpls-tp-framework): A Framework for MPLS in Transport Networks draft-ietf-mpls-tp-oam-framework: Operations, Administration and Maintenance Framework for MPLS-based Transport Networks draft-bhh-mpls-tp-oam-y1731: MPLS-TP OAM based on Y.1731 draft-ietf-mpls-tp-cc-cv-rdi: Proactive Connectivity Verification, Continuity Check and Remote Defect indication for MPLS Transport Profile draft-ietf-mpls-tp-on-demand-cv: MPLS On-demand Connectivity Verification and Route Tracing draft-ietf-mpls-tp-fault: MPLS Fault Management OAM draft-frost-mpls-tp-loss-delay: Packet Loss and Delay Measurement for the MPLS Transport Profile

  However, Y. In a network in which a device supporting 1731-based OAM and a device supporting BFD-based OAM are mixed, a device supporting only BFD-based OAM and Y. When a device that supports only 1731-based OAM is connected, there arises a problem that path monitoring cannot be performed.

  It is an object of the present invention to provide a device that only supports BFD-based OAM and Y.M. To provide an OAM packet conversion method and an OAM packet conversion apparatus capable of performing path monitoring even when an apparatus that supports only 1731-based OAM is connected.

  The OAM packet conversion method according to the present invention is an OAM packet conversion method used in a network in which a first device and a second device having different OAM schemes in MPLS-TP are mixed. MPLS-TP label header composed of LSP label, GAL label, TC and TTL of 1731-based OAM packet, OpCode and OAM type-specific information field, and LSP label, GAL label, TC and TTL of BFD-based OAM packet The information is mapped to the configured MPLS-TP label header, channel type, and information field classified by OAM type, respectively, and transferred to the second device.

  As a result, a device that supports only a BFD-based OAM corresponding to a different OAM system can be used. Path monitoring can be performed even in a network in which devices that support only 1731-based OAM coexist.

  In particular, an LSP label, a GAL label, an MPLS-TP label header composed of TC and TTL, a Channel Type, and an OAM type-specific information field of a BFD-based OAM packet received from the second device are defined in Y. The 1731-based OAM packet is mapped to an MPLS-TP label header composed of an LSP label, a GAL label, a TC, and a TTL, an OpCode, and an OAM type-specific information field and transferred to the first device.

  Further, during the mapping, Y. It is characterized in that preset default data is mapped to a data area having no corresponding information between the 1731 standard OAM packet and the BFD standard OAM packet.

  An OAM packet conversion device according to the present invention includes a receiving unit that receives a packet from a previous device, a packet separating unit that separates a packet received by the receiving unit into a data packet and a first OAM packet, Referring to the OAM conversion database, the OAM conversion database that holds information for converting one OAM packet into a second OAM packet and the first OAM packet separated by the packet separation unit with reference to the OAM conversion database. An OAM converter for converting into a second OAM packet, a packet multiplexer for multiplexing the second OAM packet converted by the OAM converter and a data packet separated by the packet separator, and the packet multiplexing And a transmitter that transmits the multiplexed packet to a subsequent apparatus.

  Thereby, path monitoring can be performed even in a network in which devices corresponding to different OAM systems coexist.

  In particular, the receiving unit receives a packet corresponding to MPLS-TP from a preceding device, and the packet separating unit converts a packet corresponding to MPLS-TP received by the receiving unit from the preceding device to a data packet and Y . 1731-based OAM packet, and the OAM conversion database is a Y.173-based OAM packet. Information for converting a 1731-based OAM packet into a BFD-based OAM packet is held. MPLS-TP label header composed of LSP label, GAL label, TC and TTL of 1731-based OAM packet, OpCode and OAM type-specific information field, and LSP label, GAL label, TC and TTL of BFD-based OAM packet Data is mapped to the configured MPLS-TP label header, channel type, and information field for each OAM type, and the packet multiplexing unit separates the BFD-based OAM packet converted by the OAM conversion unit and the packet separation unit. The packet is multiplexed, and the transmission unit transmits a packet corresponding to MPLS-TP multiplexed by the packet multiplexing unit to a subsequent apparatus.

  As a result, Y.M. OAM packets can be converted from a device supporting only 1731-based OAM to a device supporting only BFD-based OAM; Path monitoring can be performed even in a network in which 1731-based OAM and BFD-based OAM are mixed.

  Alternatively, the receiving unit receives a packet corresponding to MPLS-TP from the preceding device, and the packet separating unit receives a packet corresponding to MPLS-TP received by the receiving unit from the preceding device as a data packet and a BFD. The OAM conversion database separates the BFD-based OAM packet into the Y.OAM packet. 1731-based OAM packet information is stored, and the OAM conversion unit includes an MPLS-TP label header, a Channel Type, and an OAM composed of an LSP label, a GAL label, a TC, and a TTL of a BFD-based OAM packet. The type-specific information field is set to Y. 1731 base OAM packet LSP label, GAL label, MPLS-TP label header composed of TC and TTL, OpCode and OAM type-specific information fields are mapped respectively, and the packet multiplexing unit is converted by the OAM conversion unit Y. A 1731-based OAM packet and a data packet separated by the packet separation unit are multiplexed, and the transmission unit transmits a packet corresponding to MPLS-TP multiplexed by the packet multiplexing unit to a subsequent device. To do.

  As a result, a device that only supports BFD-based OAM can be The OAM packet can be converted to a device that supports only the 1731-based OAM. Path monitoring can be performed even in a network in which 1731 base OAM is mixed.

  In particular, Y. It is characterized in that preset default data is mapped to a data area having no corresponding information between the 1731 standard OAM packet and the BFD standard OAM packet.

  Furthermore, a switch unit for switching based on the LSP label of the packet corresponding to MPLS-TP is further provided, and operates as an MPLS-TP switch.

  Further, an OAM processing unit that performs OAM processing based on a command of the OAM packet is further provided, and the packet separation unit discriminates a packet that performs OAM conversion and a packet that does not perform OAM conversion, and performs OAM conversion. The packet is output to the OAM conversion unit, and the OAM packet not subjected to OAM conversion is output to the packet multiplexing unit.

  The OAM packet conversion method and the OAM packet conversion apparatus according to the present invention include an apparatus that supports only BFD-based OAM and Y.I. Even when a device that supports only 1731-based OAM is connected, path monitoring can be performed.

BFD-based OAM to Y.M. It is a figure which shows the structural example of the network 100 in the case of converting into 1731 base OAM. BFD-based OAM packet; It is a figure which shows the example of a format of a 1731 base OAM packet. 3 is a diagram illustrating a configuration example of an OAM conversion device 103. FIG. 5 is a flowchart showing processing of the OAM conversion apparatus 103. Y. It is a figure which shows the structural example of the network 100 in the case of converting from 1731 base OAM to BFD base OAM. 5 is a flowchart showing processing of the OAM conversion apparatus 103. BFD-based On-demand CV packet; It is a figure which shows the example of a format of a 1731 base LB packet. It is a figure which shows the example of a format of Target FEC TLV area | region. A BFD-based CC packet; It is a figure which shows the example of a format of a 1731 base CC packet. It is a figure which shows the modification of the OAM converter 103.

  Hereinafter, embodiments of an OAM packet conversion method and an OAM packet conversion apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of a network 100 using the OAM packet conversion method and the OAM packet conversion apparatus according to this embodiment. A network 100 is a network corresponding to MPLS-TP, and FIG. 1 shows an example in which an OAM packet is transmitted from the transmission apparatus 101 to the transmission apparatus 102. Here, the network 100 is a network in which transmission apparatuses corresponding to different OAM schemes coexist, and cannot directly transmit OAM packets between the transmission apparatuses. In the example of FIG. 1, the transmission apparatus 101 supports only BFD-based OAM, and the transmission apparatus 102 supports Y.I. Only 1731-based OAM is supported. Therefore, in the present embodiment, the OAM conversion device 103 is disposed between the transmission device 101 and the transmission device 102, and the BFD-based OAM packet is converted to the Y.M. It is converted into a 1731-based OAM packet and transmitted. Alternatively, Y. The 1731-based OAM packet is converted into a BFD-based OAM packet and transmitted.

  FIG. 2A is a diagram illustrating a format example of a BFD-based OAM packet. In FIG. 2A, the BFD-based OAM packet is composed of an LSP label, TC, S, TTL, GAL label, TC, S, TTL, 0001, Version, reserved, Channel Type, and an OAM type-specific information field. Is done. Here, LSP is Label Switched Pass, TC is Traffic Class, S is Bottom of Stack Indicator, TTL is Time To Live, and GAL is G-ACh Label (refer to non-patent literature for details).

  FIG. It is a figure which shows the example of a format of a 1731 base OAM packet. In FIG. 1731-based OAM packets include LSP label, TC, S, TTL, GAL label, TC, S, TTL, 0001, Version, reserved, Y. 1731 Channel Type, MEL, Version, Opcode, Flags, TLV offset, and OAM type information field. Here, MEL is MEG (Maintenance Entity Group) Level, and TLV is Type / Length / Value (refer to non-patent literature for details).

  In FIG. 2, the OAM type of the BFD-based OAM packet is stored in the channel type area 152, and the Y. The OAM type of the 1731-based OAM packet is stored in the Opcode area 155.

  As described above, since the area for storing the information indicating the OAM type is different between the two systems, the OAM packet is directly transmitted / received between the transmission apparatus 101 and the transmission apparatus 102 corresponding to only one of the OAM systems. It cannot be used. Information corresponding to each OAM type is stored in the OAM type-specific information field of the OAM PDU in both methods, but the storage location and information are not necessarily the same.

  Therefore, the OAM packet conversion apparatus 103 according to the present embodiment converts the BFD-based OAM packet transmitted from the transmission apparatus 101 into Y.P. It is converted into a 1731-based OAM packet and transmitted to the transmission apparatus 102. On the other hand, the Y.C. The 1731-based OAM packet is converted into a BFD-based OAM packet and transmitted to the transmission apparatus 101.

  Specifically, the OAM packet conversion apparatus 103 sets the OAM type stored in the channel type area 152 of the BFD-based OAM packet transmitted from the transmission apparatus 101 to the Y.OAM type. The 1731 base OAM packet is converted and mapped to the Opcode area 155 based on each standard. Also, the OAM packet conversion apparatus 103 converts the information stored in the OAM type-specific information field 153 of the BFD-based OAM packet into Y. The storage position and value are converted and mapped to the OAM type-specific information field 156 of the 1731 base OAM packet.

  On the other hand, the Y.C. The OAM type stored in the Opcode area 155 of the 1731 base OAM packet is converted and mapped to the Channel Type area 152 of the BFD base OAM packet based on each standard. Further, the OAM packet conversion apparatus 103 is a Y. The information stored in the OAM type-specific information field 156 of the 1731 base OAM packet is mapped to the OAM type-specific information field 153 of the BFD base OAM packet by converting the storage position and value.

  Note that the information in the area 151 of the BFD-based OAM packet in which the same information is stored is the Y. It is copied and mapped as it is in the area 154 of the 1731 base OAM packet.

  As described above, the OAM conversion apparatus 103 according to the present embodiment transmits / receives OAM packets to / from each other in a network in which the transmission apparatus 101 and the transmission apparatus 102 corresponding to different OAM schemes coexist.・ Maintenance can be performed.

[Configuration Example of OAM Conversion Device 103]
Next, a configuration example of the OAM conversion apparatus 103 will be described in detail. In FIG. 3, the OAM conversion apparatus 103 includes a first reception unit 201, a first packet separation unit 202, a first OAM conversion unit 203, an OAM conversion database 204, a second packet multiplexing unit 205, and a second transmission unit. 206, a second reception unit 207, a second packet separation unit 208, a second OAM conversion unit 209, a first packet multiplexing unit 210, and a first transmission unit 211.

  In the description of the present embodiment, for ease of understanding, the frame and the packet are described as being the same as the packet, but in reality, the data frame or the header portion configured by the header portion and the data packet portion is described. An OAM frame composed of an OAM packet portion is received from the previous stage, and information on each OAM packet is received as a BFD-based OAM packet and After mutual conversion between 1731-based OAM packets, an OAM frame in which a header portion is added to each OAM packet and a once separated data frame are transmitted to the subsequent stage.

  The operation of the OAM conversion apparatus 103 in FIG. 3 will be described with reference to the flowchart in FIG. 4 shows the MPLS-TP packet transmitted by the transmission apparatus 101 corresponding to the BFD-based OAM packet of FIG. Y.1731-based OAM packet The process in the case of transmitting to the transmission apparatus 102 corresponding to the 1731-based OAM packet is shown.

  (Step S <b> 101) The first receiving unit 201 receives a packet corresponding to MPLS-TP transmitted by the upstream transmission apparatus 101 corresponding to the BFD-based OAM method.

  (Step S102) The first packet separation unit 202 determines whether the MPLS-TP packet input from the first reception unit 201 is a BFD-based OAM packet or a data packet other than OAM. If it is a BFD-based OAM packet, the process proceeds to step S103, and if it is a data packet that is not a BFD-based OAM packet, the process proceeds to step S105. Whether or not the packet is an OAM packet can be determined by whether or not 13 is stored in the innermost (lowermost) label value (GAL label). Packets other than OAM packets have a label value other than 13.

  (Step S103) The first OAM conversion unit 203 obtains the OAM type in the Channel Type area 152 in FIG. 2A and information set for each OAM type stored in the data field 153 for each OAM in the PDU. To detect.

  (Step S104) The first OAM conversion unit 203 refers to the OAM conversion database 204 based on the OAM type, converts the BFD-based OAM packet to the Y.O. A 1731 base OAM packet is converted and output to the second packet multiplexing unit 205. 2A and 2B, the OAM type stored in the channel type area 152 of the BFD-based OAM packet is set to Y.O. The information stored in the OAM type-specific information field 153 of the BFD base OAM packet is mapped to the Opcode area 155 of the 1731 base OAM packet. It maps to the OAM type-specific information field 156 of the 1731 base OAM packet. Here, the corresponding conversion contents and information field positions for each OAM type are stored in advance in the OAM conversion database 204, and the first OAM conversion unit 203 executes conversion processing with reference to the OAM conversion database 204. The information in the OAM conversion database 204 can be added or changed as appropriate by a maintenance terminal or remote monitoring control.

  Note that if there is no correspondence between the two types of OAM packets, the BFD standard or Y.E. A predetermined default value according to the standard of 1731 is inserted. The “My Discriminator” area and the “Your Discriminator” area of the BFD control packet in the CC frame conversion example described later correspond to this case. Note that default information determined in advance according to the standard of each standard is stored in the OAM conversion database 204 in advance. Here, the search for the default information can be performed based on information such as a port, a label, and an OAM type.

  (Step S <b> 105) The first packet separation unit 202 transfers the separated data packets other than the OAM to the second packet multiplexing unit 205.

  (Step S <b> 106) The second packet multiplexing unit 205 converts the Y.D. after the conversion process output from the first OAM conversion unit 203. The 1731-based OAM packet and the data packet other than the OAM packet separated by the first packet separation unit 202 are multiplexed in order so as not to collide in time.

  (Step S107) The second transmission unit 206 converts the MPLS-TP packet output from the second packet multiplexing unit 205 to Y.P. It transmits to the transmission apparatus 102 corresponding to the 1731-based OAM system.

  In this way, the OAM conversion apparatus 103 converts the MPLS-TP packet transmitted by the transmission apparatus 101 corresponding to the BFD-based OAM packet to Y.P. 1731 base OAM packet, It can be transmitted to the transmission apparatus 102 corresponding to the 1731 base OAM packet.

  Next, in FIG. 1 and FIG. Although an example of conversion into a 1731 base OAM packet has been described, here, as shown in FIG. An example of converting a 1731 base OAM packet into a BFD base OAM packet will be described. In FIG. 5, the same reference numerals as those in FIG. 1 denote the same blocks. Here, Y. FIG. 6 is a flowchart of processing when the MPLS-TP packet transmitted by the transmission apparatus 102 corresponding to the 1731 base OAM packet is converted into a BFD base OAM packet and transmitted to the transmission apparatus 101 corresponding to the BFD base OAM packet. It explains using.

  (Step S <b> 201) A packet corresponding to MPLS-TP transmitted by the upstream transmission apparatus 102 corresponding to the 1731 base OAM system is received.

  (Step S202) The second packet separation unit 208 determines that the MPLS-TP packet input from the second reception unit 207 is Y.P. It is determined whether the packet is a 1731 base OAM packet or a data packet other than OAM. Y. If it is a 1731 base OAM packet, the process proceeds to step S203. If the data packet is not a 1731 base OAM packet, the process proceeds to step S205. Y. Whether or not the packet is a 1731 base OAM packet can be determined, for example, based on whether or not the OAM type is stored in the Opcode area 155 of FIG.

  (Step S203) The second OAM conversion unit 209 detects the OAM type in the Opcode area 155 in FIG. 2B and the information written in the data field 156 for each OAM in the PDU.

  (Step S204) The second OAM conversion unit 209 refers to the OAM conversion database 204 based on the OAM type, and performs Y. The 1731 base OAM packet is converted into a BFD base OAM packet and output to the first packet multiplexing unit 210. Note that the conversion method is as described in FIGS. 2 (a) and 2 (b). The OAM type stored in the Opcode 155 area of the 1731 base OAM packet is mapped to the Channel Type area 152 of the BFD base OAM packet. The information stored in the OAM type information field 156 of the 1731 base OAM packet is mapped to the OAM type information field 153 of the BFD base OAM packet. The conversion contents corresponding to each OAM type, the storage position of the information field, and the like are stored in advance in the OAM conversion database 204, and the second OAM conversion unit 209 executes conversion processing with reference to the OAM conversion database 204.

  Here, when there is no correspondence between the two types of OAM packets, the BFD standard or Y.S. A predetermined default value according to the standard of 1731 is inserted.

  (Step S205) The second packet separator 208 transfers the separated data packets other than the OAM to the first packet multiplexer 210.

  (Step S206) The first packet multiplexing unit 210 temporally combines the BFD-based OAM packet after the conversion process output from the second OAM conversion unit 209 and the data packet other than the OAM packet separated by the second packet separation unit 208. Multiplex in order so as not to collide.

  (Step S207) The first transmission unit 211 transmits the MPLS-TP packet output from the first packet multiplexing unit 210 to the transmission apparatus 101 corresponding to the BFD-based OAM scheme.

  In this way, the OAM conversion apparatus 103 is able to The MPLS-TP packet transmitted by the transmission apparatus 102 corresponding to the 1731 base OAM packet can be converted into a BFD base OAM packet and transmitted to the transmission apparatus 101 corresponding to the BFD base OAM packet.

[On-demand CV packet mapping example]
Next, an example of mapping of an On-demand CV (Connectivity Verification) packet will be described. FIG. 7A is a diagram illustrating a format example of an On-demand CV packet in a BFD-based OAM packet.

  7A, the BFD-based On-demand CV packet stores information indicating the On-demand CV packet in the Channel Type area 162 in the BFD-based OAM packet of FIG. 7A. The channel type area 162 is composed of 16 bits, and stores, for example, a value such as “0x0007 (hexadecimal number)” as information indicating an On-demand CV packet. The OAM PDU field includes a Sequence Number area 163, a Time Stamp area 164, and an LSP Target FEC TLV area 164. Here, FEC means Forwarding Equivalence Class, and TLV means Type / Length / Value (refer to non-patent literature for details). For example, as shown in FIG. 8, the Target FEC TLV format stores Global ID, Node ID, Tunnel Number, and the like on the Source side and the Destination side, respectively.

  FIG. It is a figure which shows the example of a format of a 1731 base LB packet. Y. Since the 1731-based OAM packet does not have a CV packet type, Y.P. It is converted into a 1731-based LB (Loop Back) packet.

  In FIG. In the 1731-based LB packet, a value indicating the LB function is stored in the Opcode area 168 described with reference to FIG. The Opcode area 168 is composed of 8 bits, and stores a value such as “0x02 (hexadecimal number)” as information indicating an LB packet, for example. The OAM PDU field has a Transaction / Sequence Number area 169 and a Target MEP / MIP ID TLV area 170. The Target MEP / MIP ID TLV area 170 is composed of 32 bits and stores a value such as “0x00000001 (hexadecimal number)”, for example. Here, MEP means Maintenance Entity Group End Point, and MIP means Maintenance Entity Group Intermediate Point (refer to non-patent literature for details).

  The BFD-based On-demand CV packet shown in FIG. 7A and FIG. The example in which the 1731-based LB packet is mutually converted is executed by the first OAM conversion unit 203 or the second OAM conversion unit 209 in each processing of step S104 in FIG. 4 and step S204 in FIG. 6 described above.

  For example, the region 161 having the LSP label, TC, S, TTL, GAL label, TC, S, and TTL of the BFD-based On-demand CV packet in FIG. Since the region 167 having a 1731-based LSP label, TC, S, TTL, GAL label, TC, S, and TTL has a one-to-one correspondence, the first OAM conversion unit 203 and the second OAM conversion unit 209 are each set as they are. Are mapped to each other. Further, the value (for example, “0x0007 (hexadecimal number)”) of the Channel Type field 162 indicating the BFD-based On-demand CV packet, Y. Since the value of the Opcode area 168 indicating the 1731-based LB packet (for example, “0x02 (hexadecimal number)”) cannot be mapped as it is, the first OAM conversion unit 203 and the second OAM conversion unit 209 refer to the OAM conversion database 204. Are converted into each other and then mapped to each region.

  In this way, the OAM conversion apparatus 103 according to the present embodiment converts OAM packets to each other and transmits and receives them in a network in which the transmission apparatus 101 and the transmission apparatus 102 corresponding to different OAM schemes coexist. Can be operated, managed and maintained.

  Since there is no corresponding information in the area 165 and the area 166 in the On-demand CV packet in FIG. 7A, the default information based on the BFD-based OAM packet standard is mapped with reference to the OAM conversion database 204. Is done. Similarly, the area 171 in the LB packet in FIG. 7B does not have information corresponding to the BFD-based OAM packet. Default information based on the 1731-based OAM packet standard is mapped with reference to the OAM conversion database 204.

[CC packet mapping example]
Next, a mapping example of CC (Connectivity Check) packets will be described. FIG. 9A shows a format example of a CC packet in a BFD-based OAM packet. In FIGS. 9A and 9B, areas not related to the description such as the area 151 and the area 154 in the format of FIGS. 2A and 2B are omitted.

  In FIG. 9A, 0xHH (HH is a value assigned in advance by IANA (Internet Assigned Numbers Authority)) as CC code point is stored in the Channel Type area 181 of the BFD-based OAM packet of FIG. 2A. . The value of this Channel Type region 181 is the Y. 1731-based OpCode region 185 is converted and mapped. It is stored as CCM (Continuity Check Message) = 1 indicating a 1731-based CC packet.

  In the CC packet of FIG. 9A, “Sta” is an abbreviation of “State” and indicates the current state of the BFD session. Sta indicates, for example, 0: AdminDown, 1: Down, 2: Init, 3: Up. As shown in FIG. 9B, the value of the Sta area 182 of the BFD-based CC packet is Y. The value is converted into a value in an RDI (Remote Defect Indication) area 186 in the Flags area of the 1731-based CC packet. RDI indicates a failure state, for example, RDI = 1 (True: failure has occurred) and RDI = 0 (False: no failure). Then, the first OAM conversion unit 203 and the second OAM conversion unit 209 convert, for example, Sta = 0 or 1 to RDI = 1, and convert Sta = 2 or 3 to RDI = 0.

  Similarly, the value of the region 183 of “Desired Min TX Interval” and “Required Min RX Interval” in the BFD-based CC packet of FIG. 1731-based CC packet is mapped as a value of Flags “Period” area 187 having the same function, where “Desired Min TX Interval” is a value indicating a minimum transmission interval of CC packets, and “Required Min RX” Similarly, “Interval” is a value indicating a minimum allowable reception interval of CC packets. These values are Y. 1731-based CC packet is converted and mapped to a value that matches the format of the “Period” area, for example, because the number of bits is different, mapping is performed by adjusting the unit and size of time that can be expressed. When the minimum time differs between reception and reception, the larger or smaller value may be mapped.

  In this way, BFD-based CC packets and Y.E. Information having a correspondence relationship with a 1731-based CC packet is mapped as it is or after conversion of a value stored in a region having the correspondence relationship.

  Here, the “My Discriminator” and “Your Discriminator” regions 184 in FIG. Since there is no area corresponding to the CC packet based on 1731, for example, Y. When converting a 1731-based CC packet to a BFD-based CC packet, a unique value other than 0 based on the BFD-based OAM packet standard in the “My Discriminator” and “You Discriminator” areas 184 (for example, 0x11111111) Are inserted respectively. Further, if there is an area that has no correspondence and is not defined in the standard, it is assumed that the area is not directly related to the OAM packet, and 0x00 is inserted.

  Note that the first packet separation unit 202 and the second packet separation unit 208 of the OAM conversion apparatus 103 described in FIG. 3 separate the OAM packet that performs OAM conversion from the OAM packet that does not perform OAM conversion, and performs OAM conversion. The OAM packet for performing OAM conversion is output to the first OAM conversion unit 203 and the second OAM conversion unit 209, respectively, and the OAM packet not subjected to OAM conversion is output to the second packet multiplexing unit 205 and the first packet multiplexing unit 210, respectively.

  For example, Y.M. When transferring a 1731-based OAM packet without converting it to a BFD-based OAM packet, the The 1731-based OAM packet is transferred to the subsequent apparatus without conversion, and the BFD-based OAM packet is similarly transferred to the Y. When transferring without converting to a 1731-based OAM packet, the BFD-based OAM packet is transferred to a subsequent device without being converted.

[Modification]
Next, a modification of the OAM conversion apparatus 103 described with reference to FIG. 3 will be described with reference to FIG. In the OAM conversion apparatus 103 in FIG. 3, only the function of converting OAM packets of different methods has been described. However, the OAM conversion apparatus 103 in FIG. 10 is different from the OAM conversion apparatus 103 in FIG. 212b), instead of the first transmitter 211 and the second transmitter 206, a plurality of transmitters 211a to 211b and a plurality of transmitters 206a to 206b are arranged behind the switch unit 212.

  10, the switch unit 212a determines which transmission port based on the LSP label of the MPLS-TP packet input from the second packet multiplexing unit 205 (in the example of FIG. 10, a plurality of transmission units from the transmission unit 211a to the transmission unit 211b). Is transmitted to any one of the transmission units 211b from the corresponding transmission unit 211a. Similarly, the switch unit 212b determines which transmission port (in the example of FIG. 10 a plurality of transmission units from the transmission unit 206a to the transmission unit 206b) based on the LSP label of the MPLS-TP packet input from the first packet multiplexing unit 210. Judgment is made on whether or not to transfer, and the data is output from the corresponding transmission unit 206a to any one of the transmission units 206b.

  In this way, the OAM converter 103 not only converts OAM packets of different systems, but also operates as an MPLS-TP switch.

  Note that the first packet separation unit 202 and the second packet separation unit 208 of the OAM conversion apparatus 103 described in FIG. 10 separate the OAM packet that performs OAM conversion and the OAM packet that does not perform OAM conversion, and perform OAM conversion. The OAM packet for performing OAM conversion is output to the first OAM conversion unit 203 and the second OAM conversion unit 209, respectively, and the OAM packet not subjected to OAM conversion is output to the second packet multiplexing unit 205 and the first packet multiplexing unit 210, respectively.

  For example, Y.M. The 1731-based OAM packet is transferred without conversion for the packet transferred to the Y.1731 base device, and the OAM conversion is performed for the packet transferred to the BFD base device and transferred to the subsequent device. Similarly, a packet for transferring a BFD-based OAM packet to a BFD-based device is transferred without conversion, and The packet transferred to the 1731 base device is subjected to OAM conversion and transferred to the subsequent device.

  As described above in each embodiment, the OAM packet conversion method and the OAM packet conversion apparatus 103 according to the present invention are an apparatus that supports only BFD-based OAM and Y.I. Even in a network in which devices that support only 1731-based OAM are mixed, it is possible to monitor the path in the network by mutually converting and transferring OAM packets of different systems.

  The OAM packet conversion method and the OAM packet conversion apparatus according to the present invention have been described by way of examples in the respective embodiments, but may be implemented in various other forms without departing from the spirit or main features thereof. be able to. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The present invention is defined by the claims, and the present invention is not limited to the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Network 101 ... Transmission apparatus 102 ... Transmission apparatus 103 ... OAM conversion apparatus 201 ... 1st receiving part 202 ... 1st packet separation part 203 ... 1st OAM conversion part 204 ... OAM conversion database 205 ... second packet multiplexing unit 206 ... second transmission unit 207 ... second reception unit 208 ... second packet separation unit 209 ... second OAM conversion unit 210 .. First packet multiplexing unit 211... First transmission unit 206a, 206b, 211a, 211b... Transmission unit 212, 212a, 212b.

Claims (9)

In an OAM packet conversion method used in a network in which a first device and a second device having different OAM schemes in MPLS-TP are mixed,
Y. received from the first device. MPLS-TP label header composed of LSP label, GAL label, TC and TTL of 1731-based OAM packet, OpCode and OAM type-specific information field, and LSP label, GAL label, TC and TTL of BFD-based OAM packet An OAM packet conversion method comprising: mapping each of the configured MPLS-TP label header, channel type, and information field according to OAM type to the second device. The OAM packet conversion method according to claim 1,
An MPLS-TP label header composed of an LSP label, a GAL label, a TC and a TTL of a BFD-based OAM packet received from the second device, a channel type, and an OAM type-specific information field An OAM that is mapped to an MPLS-TP label header composed of LSP label, GAL label, TC, and TTL, OpCode, and OAM type information fields of 1731-based OAM packets, and forwards to the first device. Packet conversion method. The OAM packet conversion method according to claim 2, wherein
At the time of mapping, Y. An OAM packet conversion method characterized by mapping preset default data to a data area having no corresponding information between an OAM packet of 1731 standard and an OAM packet of BFD standard. A receiver for receiving a packet from the preceding device;
A packet separator that separates a packet received by the receiver into a data packet and a first-system OAM packet;
An OAM conversion database that holds information for converting the first OAM packet into the second OAM packet;
An OAM conversion unit that converts the OAM packet of the first method separated by the packet separation unit into the OAM packet of the second method with reference to the OAM conversion database;
A packet multiplexing unit that multiplexes the OAM packet of the second method converted by the OAM conversion unit and the data packet separated by the packet separation unit;
A transmission unit that transmits the packet multiplexed by the packet multiplexing unit to a subsequent device; The OAM packet converter according to claim 4, wherein
The receiving unit receives a packet corresponding to MPLS-TP from the preceding apparatus,
The packet demultiplexing unit converts a packet corresponding to MPLS-TP received by the receiving unit from a preceding device into a data packet and a Y. To 1731-based OAM packets,
The OAM conversion database is Y. Holds information for converting 1731-based OAM packets to BFD-based OAM packets,
The OAM converter is a Y. MPLS-TP label header composed of LSP label, GAL label, TC and TTL of 1731-based OAM packet, OpCode and OAM type-specific information field, and LSP label, GAL label, TC and TTL of BFD-based OAM packet Map to the configured MPLS-TP label header, Channel Type and OAM type information fields,
The packet multiplexer multiplexes the BFD-based OAM packet converted by the OAM converter and the data packet separated by the packet separator,
The OAM packet conversion device, wherein the transmission unit transmits a packet corresponding to MPLS-TP multiplexed by the packet multiplexing unit to a subsequent device. The OAM packet converter according to claim 4, wherein
The receiving unit receives a packet corresponding to MPLS-TP from the preceding apparatus,
The packet separation unit separates a packet corresponding to MPLS-TP received by the reception unit from a previous device into a data packet and a BFD-based OAM packet,
The OAM conversion database stores BFD-based OAM packets as Y.P. Holds information for conversion to 1731-based OAM packets,
The OAM converting unit includes an MPLS-TP label header composed of an LSP label, a GAL label, a TC, and a TTL of a BFD-based OAM packet, a Channel Type, and an OAM type-specific information field. Mapping to the LSP label, GAL label, MPLS-TP label header composed of TC and TTL, OpCode and OAM type-specific information fields of the 1731-based OAM packet,
The packet multiplexing unit includes a Y.P signal converted by the OAM conversion unit. A 1731-based OAM packet and a data packet separated by the packet separation unit;
The OAM packet conversion device, wherein the transmission unit transmits a packet corresponding to MPLS-TP multiplexed by the packet multiplexing unit to a subsequent device. The OAM packet converter according to claim 5 or 6,
At the time of mapping, Y. An OAM packet converter characterized by mapping preset default data in a data area having no corresponding information between a 1731 standard OAM packet and a BFD standard OAM packet. In the OAM packet conversion device according to any one of claims 4 to 7,
An OAM packet converter characterized by further comprising a switch unit that performs switching based on an LSP label of a packet corresponding to MPLS-TP, and operating as an MPLS-TP switch. In the OAM packet conversion device according to any one of claims 4 to 8,
The packet separation unit discriminates between a packet that performs OAM conversion and a packet that does not perform OAM conversion, and outputs an OAM packet that performs OAM conversion to the OAM conversion unit. OAM packet conversion apparatus characterized by being output to the unit.

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