WO2010043149A1 - Method, network node and communication system for virtual circuit connectivity verification - Google Patents

Abstract

A method, a network node and a communication system for Virtual Circuit Connectivity Verification are provided. In the communication system, a detection  initiating node transmits a Virtual Circuit Connectivity Verification request message to a detection terminating node, the Virtual Circuit Connectivity Verification request message carries a hop number of the pseudo wire between the detection initiating node and the detection terminating node, the detection initiating node receives a response message and implements Virtual Circuit Connectivity Verification according to the time-to-live value in the response message; the detection terminating node receives the Virtual Circuit Connectivity Verification request message, and determines whether the received Virtual Circuit Connectivity Verification request message is terminated in the current node; if the received Virtual Circuit Connectivity Verification request message is terminated in the current node, the response message is generated and transmitted to the detection initiating node, wherein, the time-to-live value in the response message is set as the hop number of the pseudo wire between the detection terminating nodes. The problem of connectivity in MS-PW is solved by adopting the technical scheme of the invention.

Description

 Instruction manual

 Title of Invention: A method for virtual circuit connectivity checking, network nodes, and communication systems

 [1] This application claims the priority of the Chinese application filed on October 15, 2008, with the application number 200810224464.5, entitled "A method for virtual circuit connectivity check, network node and communication system", The entire contents are incorporated herein by reference.

[2] Technical field

 [3] The present invention relates to the field of communications technologies, and in particular, to a method, a network node, and a communication system for checking a virtual circuit connectivity.

[4] Background of the invention

 [5] Pseudo Wire (PW) is divided into single-hop virtual pseudowires (Single Segment Pseudo)

Wire, SS-PW) and multi-hop virtual pseudowires (Multi Segment Pseudo

 Wire, MS-PW). Both SS-PW and MS-PW can check for virtual circuit connectivity defects through Virtual Circuit Connectivity Verification (VCCV).

[6] In MS-PW, refer to Figure 1, the virtual pseudowire termination provider edge device in the existing mode (P

W Terminating Provider Edge (T-PE) Checking Virtual Pseudo Switching Point Provider Edge Device by VCCV (PW Switching Provider)

 The connectivity of the Edge and S-PE is as follows: T-PE1 sends a virtual circuit connectivity check ping request (VCCV Ping Request) message according to the selected VCCV type; T-PE1 will be compliant according to the protocol according to the selected VCCV type. The method sends the VCCV Ping Request message to the S-PE; the S-PE receives the message, and will survive in order to maintain the check (Time To Live)

 , TTL) value is set to a large value, such as 255; TTL value is not zero, S-PE forwards the received packet, T-PE1 is the end point of PW, and the packet is successfully sent to T-PE1 Processing on. Referring to Figure 1, T-PE1 checks the connectivity of T-PE2 through VCCV as follows: T-PE1 sends a VCCV Ping Request message; T-PE1 pings the VCCV through the protocol.

The packet is sent to the T-PE2. The T-PE2 receives the packet and sets the TTL value to a large value. The T-PE2 sends the packet to the S-PE according to the transmission path. The TTL value is not zero. S-PE determines that it is not based on the value of TTL. It is the endpoint. After receiving the received packet, T-PE1 may eventually receive the returned packet. In the process of implementing the present invention, the inventors have found that at least the following problems exist in the prior art:

If the S-PE wants to actively check the pseudowire status of other devices (such as T-PE1 or T-PE2) by VCCV, the S-PE can receive the T-PE1 because it cannot accurately set the TTL value. After the VCCV ping reply message sent by the T-PE2, the S-PE forwards the packet as long as the TTL value is not zero. The result of the check is not determined to be between the S-PE and other devices. The state of the pseudowire, so in the multi-hop virtual pseudowire virtual circuit connectivity check process, the S-PE actively checks the pseudowire state of other devices through the VCCV mode.

[8] Summary of the invention

 [9] Embodiments of the present invention provide a method, network node, and system for checking virtual circuit connectivity, which solves the connectivity problem in MS-PW.

[10] An embodiment of the present invention provides a method for checking a virtual circuit connectivity, including:

[11] receiving a virtual circuit connectivity check request packet, where the virtual circuit connectivity check request packet carries a hop count of the virtual pseudowire between the detection initiator node and the detection termination node;

 [12] Determining whether the received virtual circuit connectivity check request message is terminated at the local node; if the received virtual circuit connectivity check request message is terminated at the local node, a response message is generated and sent, where The survival time value in the response message is set to the hop count of the virtual pseudowire.

 [13] The embodiment of the present invention further provides a method for checking a virtual circuit connectivity, including:

 [14] generating a virtual circuit connectivity check request packet, where the virtual circuit connectivity check request packet carries a hop count of the virtual pseudowire between the detection initiator node and the detection termination node, so that the detection termination node is based on the Detecting the virtual pseudowire hop count between the initiating node and the detecting termination node to set the survival time value in the response message;

[15] Receive a response message and perform a virtual circuit connectivity check based on the lifetime value in the response message.

 An embodiment of the present invention provides a network node, including:

 [17] The sending module 302 is configured to send a virtual circuit connectivity check request packet, where the virtual circuit connectivity check request packet carries a hop count of the virtual pseudowire between the detecting initiator node and the detecting termination node, so that The detecting termination node sets a survival time value of the response packet according to the hop count of the virtual pseudowire between the detection initiation node and the detection termination node;

[18] The receiving module 303 is configured to receive a response message. [19] The connectivity check module 304 is configured to perform a virtual circuit connectivity check according to the survival time value in the response message.

 [20] The embodiment of the present invention further provides a network node, including:

 [21] The receiving module 401 is configured to receive a virtual circuit connectivity check request packet, where the request carries a hop count of the virtual pseudowire between the detecting initiator node and the detecting termination node;

[22] The response message generating module 402 is configured to determine that the virtual circuit connectivity check request message is after its termination.

And generating and sending a response message, where the survival time value in the generated response message is the hop count of the virtual pseudowire;

 [23] The sending module 403 is configured to send the response message.

[24] The embodiment of the present invention further provides a network node, including:

 [25] The request packet sending and receiving module 501 is configured to receive and forward the virtual circuit connectivity check request packet, and determine that the virtual circuit connectivity request packet is not terminated at the local node, and the virtual circuit connectivity check is forwarded. a request packet, where the virtual circuit connectivity request packet carries a hop count of the virtual pseudowire between the detection initiation node and the detection termination node, so as to detect that the termination node is based on the virtual pseudo between the detection initiation node and the detection termination node. The hop count of the line sets the lifetime value of the response message;

 [26] The response message sending and receiving module 502 is configured to receive the response message, determine that the received response message is not terminated by the node, modify the survival time value in the response message, and forward the modified response message.

 [27] An embodiment of the present invention provides a communication system, including: a detection initiation node and a detection termination node:

[28] The detection initiation node sends a virtual circuit connectivity check request message to the detection termination node, where the virtual circuit connectivity check request message carries a hop of the virtual pseudowire between the detection initiation node and the detection termination node. And receiving the response message sent by the detection termination node, and performing virtual circuit connectivity check according to the survival time value in the response message;

 [29] The detection termination node receives the virtual circuit connectivity check request message sent by the detection initiation node, and determines whether the received virtual circuit connectivity check request message is terminated at the local node; if the received virtual The circuit connectivity check request message is terminated at the local node, and generates and sends a response message to the detection initiator node, where the survival time value in the response message is set to the hop count of the virtual pseudowire.

According to the technical solution provided by the foregoing embodiment of the present invention, the embodiment of the present invention carries the survival time value required to be filled in the response packet of the detection termination node in the virtual circuit connectivity check request message. The detection termination node can accurately set the survival time, and solves the problem that the S-PE cannot actively detect the connectivity with other devices through the VCCV in the prior art, and uses the technical solution provided by the present invention to make the existing In the technology, T-PE actively detects the connectivity of other devices. By setting the TTL value accurately, the inspection process is more convenient and efficient.

[31] BRIEF DESCRIPTION OF THE DRAWINGS

 [32] FIG. 1 is a schematic diagram of an application scenario of a virtual circuit connectivity check in the prior art;

2A is a flowchart of a method for checking connectivity of a virtual circuit according to an embodiment of the present invention;

2B is a flowchart of a method for checking connectivity of a virtual circuit according to another embodiment of the present invention;

FIG. 3 is a simplified structural diagram of a network node according to an embodiment of the present invention; FIG.

FIG. 4 is a simplified structural diagram of a network node according to another embodiment of the present invention; FIG.

FIG. 5 is a simplified structural diagram of a network node according to another embodiment of the present invention; FIG.

6 is a simplified structural diagram of a communication system according to an embodiment of the present invention.

[39] Mode for carrying out the invention

 In the embodiment of the present invention, the detecting initiating node sends a virtual circuit connectivity check request (VCCV Ping).

Request) After the packet is received, the VCCV ping request carries the TTL value that the termination node needs to set in the VCCV ping reply packet to detect that the termination node can be based on The TTL value of the VCCV ping reply packet is set in the VCCV ping reply packet, and the TTL value in the VCCV ping reply packet sent by the detecting termination node is between the detection initiator node and the detection initiator node. The exact number of hops, the response message will be accurately and quickly sent to the intended device to complete the connectivity detection. The embodiment of the present invention solves the problem that the S-PE cannot actively check the connectivity of the virtual pseudowire virtual circuit with other devices through the VCCV mode in the prior art, and the technical solution described in the embodiment of the present invention is also used. In the prior art, the T-PE actively checks the connectivity with other devices through the VC CV more quickly and conveniently.

[41] As shown in FIG. 2A, a method for checking a virtual circuit connectivity in a communication system, taking a communication system including two nodes as an example, as shown in FIG. 2A, a detection initiation node and a detection termination node, detecting an initiation node and The detection termination node does not include a detection intermediate node, where the detection initiation node represents the node that initiates the detection request, the detection termination node represents the node that terminates the detection request, and the detection intermediate node represents the node of the transit detection request, and the virtual circuit connectivity check method include: [42] Step S202: The detecting initiating node generates a virtual circuit connectivity check request message.

 [43] The virtual circuit connectivity check request packet carries the hop count of the virtual pseudowire between the detection initiation node and the detection termination node; the virtual circuit connectivity check request packet further carries the destination IP address and the virtual Pseudo line identifier

, where the destination IP address is the IP address of the detection termination node.

[44] The hop count of the virtual pseudowire between the detecting initiator node and the detecting terminal node may be determined by a network structure or other parameters, or may be determined by user configuration.

[45] Step S204: Detect the virtual circuit connectivity check request message sent by the initiating node.

[46] Step S206: The detecting termination node receives the virtual circuit connectivity check request packet, and determines that the virtual circuit connectivity check request packet is terminated at the local node, and generates a response packet, where the TTL value in the response packet is Detect the number of hops of the virtual pseudowire between the initiating node and the detecting end node.

[47] The method for determining whether the virtual circuit connectivity check request message is terminated at the local node may include: parsing the virtual circuit connectivity check request packet to obtain the destination IP address, and matching the destination IP address with the IP address of the local node, If the matching is performed, it is determined that the virtual circuit connectivity check request packet is terminated at the local node. If the matching is not performed, the virtual circuit connectivity check request packet is not terminated at the local node; or, the virtual circuit connectivity check is parsed. The request packet obtains the destination IP address and the virtual pseudowire identifier, and the destination IP address and the virtual pseudowire identifier are respectively matched with the IP address of the local node and the virtual pseudowire identifier. If yes, the virtual circuit connectivity check request packet is determined. It is terminated at the local node. If it does not match, it is determined that the virtual circuit connectivity check request message is not terminated at the local node.

 [48] Step S208: Detecting that the terminating node sends the generated response message.

 [49] Step S210: After detecting the response message, the initiating node determines that the response message is terminated according to the TTL value, terminates the forwarding process of the response message, and performs corresponding processing to complete the detection process.

 [50] After detecting that the initiating node receives the response message, it can determine that the virtual circuit connectivity between the detecting initiating node and the detecting end node is normal.

[51] Specifically, after detecting that the initiating node receives the response packet, the TTL value carried in the response packet is parsed. When the TTL value is 1 or the TTL value is decreased to 0, the response message is At the end of itself, the forwarding process of the response message is terminated. Further, the detection end point may be combined with the TTL value and the destination IP address in the response packet to determine whether the response message is terminated at the local node, for example, the TTL value is reduced to 1 to 0, and the central processing unit is triggered. , CPU) processing the response message, such as the CPU will The destination IP address in the response packet matches the IP address of the local node. If it matches, it is determined that the response packet is terminated at the local node. The CPU may also check whether the node has sent a virtual circuit connectivity check request packet according to the virtual pseudowire identifier in the response packet and the virtual pseudowire identifier saved by the node, so as to ensure that the connectivity check is more accurate. reliable.

The hop count of the virtual pseudowire between the detection initiation node and the detection termination node is encapsulated into the virtual circuit connectivity check request packet according to the type-Length-Value (TLV) coding format. In the field. The coding format of the TLV is shown in Table 1. The number of hops of the virtual pseudowire between the initiating node and the detecting end node is filled in the value.

 The meanings of the fields in the TLV information field are as shown in Table 2 below:

 [55]

 [56] For example, as shown in FIG. 2A, the communication system includes two nodes, a detection initiation node and a detection termination node, and the detection initiation node and the detection termination node do not include a detection intermediate node, and when the detection initiation node initiates detection, the detection is initiated. The number of virtual pseudowire PW hops between the node and the detection termination node is 1, and the value in the information field is filled with 1. After detecting that the initiating node receives the response packet, it parses the TTL value carried in the response packet. When the TTL value is 1 or the TTL value is decreased by 1 to 0, the response message is terminated at itself, and the response is terminated. Packet forwarding process.

[57] The hop count of the virtual pseudowire between the detecting initiator node and the detecting termination node is determined according to the networking structure, for example, according to one or more of network topology parameters, virtual pseudowire list, and virtual pseudowire algorithm. To determine; the number of hops of the virtual pseudowire between the initiating node and the detecting end node can also be determined by the user configuration. The step of determining the number of hops of the virtual pseudowire between the detecting initiating node and the detecting terminating node may be determined locally by the detecting initiating node, or may be determined and provided by the central control node or the serving node. Test the originating node.

 [58] FIG. 2B shows another embodiment of a method for checking the connectivity of a virtual circuit in a communication system. The embodiment takes three nodes as an example. As shown in FIG. 2B, the detection initiation node and the detection termination node detect the initiating node. The detection termination node includes a detection intermediate node, and the number of virtual pseudowire hops between the detection initiation node and the detection termination node is 2, where the detection initiation node represents the node that initiates the detection request, and the detection termination node represents the termination detection request. a node, detecting a node in which the intermediate node represents a transit detection request, the method includes:

[59] Step S202': The detection initiation node generates a virtual circuit connectivity check request message, where the virtual circuit connectivity check request message carries the hop count of the virtual pseudowire between the detection initiation node and the detection termination node; In this embodiment, the hop count is 2; the manner in which the hop count is carried in the virtual circuit connectivity check request packet is the same as that in FIG. 2A, and is not described. The virtual circuit connectivity check request message may further include detecting a destination IP address and a virtual pseudowire identifier of the terminating node.

 [60] Step S204': Detecting the virtual circuit connectivity check request message sent by the initiating node.

 [61] Step S205': After detecting the virtual circuit connectivity check request message, the intermediate node determines whether the virtual circuit connectivity check request message is terminated at the local node.

 [62] The method for determining whether the virtual circuit connectivity check request message is terminated at the local node may be the same as the corresponding description in step S206 in FIG. 2A, and is not described.

 [63] Step S204": If it is detected in step S205' that the intermediate node determines that the virtual circuit connectivity check request message is not terminated at the local node, the detecting intermediate node continues to send the virtual circuit connectivity check request message, where The detecting intermediate node does not modify the hop count of the virtual pseudowire between the detecting initiator node and the detecting termination node in the virtual circuit connectivity check request message.

 [64] Step S206': After detecting that the termination node receives the virtual circuit connectivity check request packet, it determines that the virtual circuit connectivity check request packet is terminated at the local node, and generates a response packet, where the detection endpoint node is based on Detecting the TTL value of the hop count of the virtual pseudowire between the initiating node and the detecting end node, and setting the TTL value to detect the hop count of the virtual pseudowire between the initiating node and the detecting end node; It may include a destination IP address and a virtual pseudowire identifier (ie, detecting an IP address of the initiating node and a virtual pseudowire identifier).

The method for determining whether the virtual circuit connectivity check request message is terminated at the local node may refer to the corresponding description in step S206, and is not described. [66] Step S208': detecting that the terminating node sends the generated response message.

 [67] Step S209': After detecting that the intermediate node receives the response message, it determines whether the response message is terminated at the node.

 [68] Step S208": If it is detected in step S209 that the intermediate node determines that the response message is not terminated at the local node, the detecting intermediate node continues to send the response message, wherein the TTL value in the response message sent by the intermediate node is detected according to the protocol. Minus 1.

 [69] Step S210': After detecting that the initiating node receives the response message sent by the intermediate node, the virtual circuit connectivity check is performed according to the TTL value in the response message.

[70] Specifically, according to the TTL value in the response message, it is determined that the response message is terminated at the local node, the forwarding process of the response message is terminated, and the corresponding processing is performed to complete the detection process. This step is the same as step S210 in Fig. 2A, and will not be described here.

As shown in FIG. 3, a network node 300 according to an embodiment of the present invention includes:

[72] The request message generating module 301 is configured to generate a virtual circuit connectivity check request message, where the virtual circuit connectivity check request message carries a hop of the virtual pseudowire between the detection initiation node and the detection termination node. Number, in order to detect that the terminating node sets the TTL value in the response message based on the number of hops of the virtual pseudowire between the detecting initiating node and the detecting terminating node;

 [73] The sending module 302 is configured to send the virtual circuit connectivity check request message generated by the request message generating module 301 to the communication system;

[74] The receiving module 303 is configured to receive a response packet.

 [75] The connectivity check control module 304 is configured to perform a virtual circuit connectivity check according to the TTL value in the response packet.

 [76] The network node in the embodiment of the present invention may be a detection initiation node, and the detection termination node can accurately set the TTL value of the survival time, and the TTL is not set to be large (such as 255), as in the prior art. The network node of the embodiment of the invention can quickly complete the check of the virtual circuit connectivity between the devices.

 As shown in FIG. 4, a network node 400 according to another embodiment of the present invention includes:

 [78] The receiving module 401 is configured to receive a virtual circuit connectivity check request packet, where the request carries a hop count of the virtual pseudowire between the detecting initiator node and the detecting termination node.

[79] The response message generating module 402 is configured to determine that the virtual circuit connectivity check request message is after its termination. And generating a response message, where the survival time in the generated response message is the hop count of the virtual pseudowire. The generated response packet may further include a destination IP address and a virtual pseudowire identifier, where the destination IP address is an IP address of the detection initiator node.

[80] The sending module 403 is configured to send the response message generated by the response message generating module 402.

As shown in FIG. 5, a network node 500 according to another embodiment of the present invention includes:

[82] The request packet sending and receiving module 501 is configured to receive and forward the virtual circuit connectivity check request packet, and determine that the virtual circuit connectivity request packet is not terminated at the local node, and the virtual circuit connectivity check is forwarded. a request packet, where the virtual circuit connectivity request packet carries a hop count of the virtual pseudowire between the detection initiation node and the detection termination node, so as to detect that the termination node is based on the virtual pseudo between the detection initiation node and the detection termination node. The hop count of the line sets the lifetime value of the response packet; here, the hop count of the virtual pseudowire in the forwarded virtual circuit connectivity check request message is not modified.

[83] The response message sending and receiving module 502 is configured to receive the response message, determine that the received response message is not terminated by the node, modify the survival time value in the response message, and forward the modified response message.

[84] The network node ₅₀₀ may further include a connectivity detection control module 503, configured to determine that the virtual circuit connectivity check request message received by the request message transceiver module 501 is not after the end of the node, the control request message transceiver module The 501 forwards the virtual circuit connectivity check request message, and determines that the response message received by the response message sending and receiving module 502 is not in the TTL of the local device termination control response packet sending and receiving module 502 to modify the response message. After the value is forwarded, the modified response message is forwarded. The control function of the request packet sending and receiving module 501 can be integrated in the request packet sending and receiving module 501, and the control function of the response detecting and receiving module 503 can be integrated into the response packet. In the transceiver module 502.

 As shown in FIG. 6, a communication system 600 according to an embodiment of the present invention, a communication system 600 includes at least two nodes, such as nodes 610a, 610b, 610c, 610d, and 620a, 620b in FIG. 610a, 6 10b 610c, 610d are terminating edge devices disposed in the network system, collectively referred to as terminating nodes 610. Nodes 620a, 620b are switching devices disposed in the network system, collectively referred to as switching nodes 620.

[86] One of the two nodes in the communication system 600 can serve as a detection initiation node, and the other of the two nodes serves as a detection termination node, and between the detection initiation node and the detection termination node according to FIG. 2A or FIG. 2B. In the manner of performing virtual pseudowire virtual circuit connectivity check, specific virtual pseudowire virtual circuit connectivity The inspection process is described above and is not mentioned.

[87] Specifically, in the communication system supporting MPLS, the terminating node 610 is a PW Terminating Provider Edge (T-PE), and the switching node 620 is a virtual pseudowire switching point provider edge. PW Switching Provider Edge (S-PE).

 The technical solution described in the embodiment of the present invention not only solves the problem that the S-PE can not actively perform VCCV detection, which is not implemented in the prior art, and is also more convenient for the prior art T-PE to detect other devices. In order to facilitate the understanding of the technical solutions of the embodiments of the present invention, the following further describes the specific application examples.

 In the application example of the present invention, the control channel (CC) type of VCCV has the following three modes:

 Type 1 : PW E3 control word mode of the first 4 bits at 0001b;

 [91] Type 2: Multi-Protocol Label Switching (MPLS) routing alarm label

[92] Type 3: Time To Live (TTL) carried in the MPLS PW tag == 1.

[93] Application Example 1:

 [94] Referring to Figure 1, T-PE1 checks the S-PE connectivity through VCCV:

 [95] Step S701: T-PE1 determines the hop count of the PW between the T-PE1 and the S-PE, and encapsulates the hop count of the PW between the T-PE1 and the S-PE into the virtual circuit connectivity check request message. .

[96] For example, T-PE1 determines that the number of hops of the PW between the T-PE1 and the S-PE is 1. After the virtual circuit connectivity check request message is generated, the hop count of the PW is encapsulated according to the TLV coding format. In the virtual circuit connectivity check request message, the value of the Value field of the TLV is set to the hop count of the PW.

[97] Step S702: The T-PE1 sends the virtual circuit connectivity check request packet to the S-PE according to the set VCCV type according to the protocol.

[98] For example, the type 1 or type 3 V in the VCCV is used to send the virtual circuit connectivity check request message to the S-PE according to the VCCV protocol.

[99] Step S703: The S-PE receives the virtual circuit connectivity check request packet, and determines that the virtual circuit connectivity check request packet is terminated by itself, and the virtual circuit connectivity check request packet is carried in the virtual circuit connectivity check request packet. The hop count of the PW between the T-PE1 and the S-PE is encapsulated into the response packet as a TTL value. [100] Step S704: The S-PE sends a response packet to the T-PE1 according to the VCCV protocol.

 [101] Step S705: The T-PE1 receives the response packet, and determines that the response packet is terminated by the device according to the TTL value in the response packet, and the response packet forwarding process is terminated, and corresponding processing is performed to complete the check. For details, refer to the description of step S210 above, and no longer comment.

[102] Application example 2:

 [103] Referring to Figure 1, the T-PE1 checks the connectivity of T-PE2 through VCCV, including:

 [104] Step S801: The T-PE1 determines the hop count of the PW between the T-PE1 and the T-PE2, and encapsulates the hop count of the PW between the T-PE1 and the T-PE2 into the virtual circuit connectivity check request report. Text.

[105] For example, T-PE1 determines that the number of hops of the PW between T-PE1 and T-PE2 is 2. In the request message, the value of the Value field of the TLV is set to 2 according to the TLV encoding format, and is encapsulated into Virtual circuit connectivity check request message

[106] Step S802: The T-PE1 sends the virtual circuit connectivity check request packet to the T-PE2 through the S-PE according to the set VCCV type.

[107] For example, the VCCV type is type 1 or type 3, and different protocol specifications are selected depending on the type. Here, the S-PE does not modify the hop count of the PW between T-PE1 and T-PE2 in the virtual circuit connectivity check request message.

 [108] Step S803: The T-PE2 receives the virtual circuit connectivity check request packet, and uses the hop count of the PW between the T-PE1 and the T-PE2 carried in the virtual circuit connectivity check request packet as the TTL. The value is encapsulated into the response packet. The TTL value of the response packet in this application instance is set to the hop count of the PW.

 [109] Step S804: The T-PE2 sends a response packet according to the transmission path, and the response packet is sent to the S-PE.

 [110] Step S805: The S-PE receives the response packet, parses the TTL value, and determines that the response packet is not terminated by itself according to the TTL value, and the response packet is forwarded. The TTL value in the response packet sent by the S-PE is modified. Specifically, the S-PE decrements the TTL value after parsing into a new response packet or subtracts 1 from the TTL value obtained by the parsing. The value of the TTL in the response packet is replaced.

 [111] Specifically, if the number of hops of the PW between the T-PE1 and the T-PE2 is 2, and the value of the TTL value obtained by the S-PE is less than 1, the response packet is sent to the VCCV protocol. T-PE1.

[112] Step S806: The T-PE1 receives the response packet, determines that the response packet is terminated by itself according to the TTL value in the response packet, terminates the response packet forwarding process, and performs corresponding processing to complete the check. [113] For example, determining whether the response packet is terminated on the local device according to the TTL value may be: determining whether the TTL obtained by the parsing is 1 or determining whether the TTL obtained by the parsing is 0 after the parsing, and if not, determining the response packet. It is not terminated at the device. If yes, it is determined that the response message is terminated at its own; or it is combined with the TTL value and the destination IP address in the response message.

 [114] Wherein, in the above embodiment, only the PW hop count between T-PE1 and T-PE2 is equal to 2, and the scheme can also be extended to PW between T-PE1 and T-PE2.

 The case where the number of hops is greater than 2. PW between T-PE1 and T-PE2

 When the hop count is greater than 2, the process of forwarding processing according to the transmission path between the S-PE and the S-PE is also included, and the principle is the same as that of the S-PE to the T-PE1/T-PE2, and is no longer praised. .

[115] Application Example 3:

 [116] Referring to FIG. 1, a connectivity check method performed by the S-PE as a detection initiator node.

 [117] The method for checking the connectivity of the T-PE1 through the VCCV by the S-PE is described as an example. The method includes

[118] Step S901: The S-PE determines the number of hops of the PW between the S-PE and the T-PE1, and the P between the S-PE and the T-PE1.

The hop count of W is encapsulated into the virtual circuit connectivity check request message.

[119] For example, the S-PE determines that the number of hops of the PW between the S-PE and the T-PE1 is 1. After the virtual circuit connectivity check request packet is generated, the hop count of the PW is encapsulated according to the format of the TLV. In the virtual circuit connectivity check request message

[120] Step S902: The S-PE sends the virtual circuit connectivity check request packet to the T-PE1 according to the set VCCV type in the manner specified by the protocol.

[121] Step S903: The T-PE1 receives the virtual circuit connectivity check request packet, and encapsulates the hop count of the PW in the virtual circuit connectivity check request packet into the response packet as a TTL value.

[122] Step S904: The T-PE1 sends a response packet to the S-PE according to the transmission path.

 [123] Step S905: The S-PE receives the response packet, determines that the packet is terminated by itself according to the TTL value in the response packet, terminates the response packet forwarding process, and performs corresponding processing on the response packet to complete the check. .

 [124] The method for the S-PE to check the connectivity of the T-PE2 through the VCCV is the same as the method for the S-PE to check the connectivity of the T-PE1 through the VCCV, and is not mentioned here.

[125] It is worth noting that: in the above embodiment, only the hop count of PW between S-PE1 and T-PE1/T-PE2 The example is equal to 1 and the scheme can also be extended to the case where the hop count of the PW between S-PE1 and T-PE1/T-PE2 is greater than 1. PW between T-PE1 and T-PE2

When the hop count is greater than 1, the process of forwarding processing according to the transmission path between the S-PE and the S-PE is also included, and the principle is the same as that of the S-PE to the T-PE1/T-PE2, and the description is not repeated. .

 A person skilled in the art can understand that all or part of the process of implementing the above embodiment method can be completed by a computer program to instruct related hardware, and the program can be stored in a computer readable storage medium. After execution, the flow of an embodiment of the methods as described above may be included. The storage medium may be a magnetic disk, an optical disk, or a read-only storage memory (Read-Only)

 Memory, ROM) or Random Access Memory (RAM).

Claims

Claim A method for checking a virtual circuit connectivity, comprising: Receiving a virtual circuit connectivity check request packet, where the virtual circuit connectivity check request packet carries the hop count of the virtual pseudowire between the detection initiator node and the detection termination node; determining the received virtual circuit connectivity check Whether the request packet is terminated at the local node; if the received virtual circuit connectivity check request message is terminated at the local node, a response packet is generated and sent, where the survival time value in the response packet is set to The number of hops of the virtual pseudowire. The method according to claim 1, wherein the hop count of the virtual pseudowire between the detecting initiating node and the detecting terminating node is encapsulated into a virtual circuit connectivity check request report in a type-length-value encoding format. In the text. A virtual circuit connectivity check method, the method includes: generating and transmitting a virtual circuit connectivity check request packet, where the virtual circuit connectivity check request packet carries a detection initiation node and Detecting the hop count of the virtual pseudowire between the termination nodes, so as to detect that the termination node sets the survival time value in the response packet based on the hop count of the virtual pseudowire between the detection initiation node and the detection termination node; The response packet is received, and the virtual circuit connectivity check is performed according to the survival time value in the response packet. The method according to claim 3, wherein the process of performing virtual circuit connectivity check according to the survival time value in the response message comprises: parsing the response message to obtain a survival time value, and when the survival value is 1 or decrement the survival value by 1 to 0, and determine that the response message is terminated at the end of the node, and the forwarding process of the response message is terminated. The method according to claim 3, wherein the process of performing virtual circuit connectivity check according to the survival time value in the response message comprises: parsing the response message to obtain a survival value and a destination IP address, when If the value is 1 or the value of the lifetime is reduced to 1 and the destination IP address matches the IP address of the local node, the response packet is terminated at the local end and the forwarding of the response packet is terminated. A network node, comprising: The request packet generating module (301) is configured to generate a virtual circuit connectivity check request packet, where the virtual circuit connectivity check request packet carries the hop count of the virtual pseudowire between the detecting initiator node and the detecting termination node. So that the detection termination node sets the survival time value of the response message according to the hop count of the virtual pseudowire between the detection initiation node and the detection termination node;  a sending module (302), configured to send the generated virtual circuit connectivity check request message, and a receiving module (303), configured to receive the response message;  The connectivity check module (304) is configured to perform a virtual circuit connectivity check according to the survival time value in the response message.  [Claim 7] A network node, comprising:  a receiving module (401), configured to receive a virtual circuit connectivity check request packet, where the request carries a hop count of a virtual pseudowire between the detecting initiating node and the detecting end node; and a response message generating module (402), configured to Determining the virtual circuit connectivity check request message is generated after the end of the self-terminating, and the survival time in the generated response message is the hop count of the virtual pseudo-line;  The sending module (403) is configured to send the response message.  [Claim S] A network node, wherein the network node comprises:  The request packet sending and receiving module (501) is configured to receive and forward the virtual circuit connectivity check request message, and determine that the virtual circuit connectivity request message is not terminated at the local node, and the virtual circuit connectivity check request is forwarded. a packet, where the virtual circuit connectivity request packet carries a hop count of the virtual pseudowire between the detection initiation node and the detection termination node, so as to detect that the termination node is based on the virtual pseudowire between the detection initiation node and the detection termination node. The hop count sets the survival time value of the response message; the response message transceiver module (502) is configured to receive the response message, and determine that the received response message is not terminated at the end of the node, and the survival of the response message is modified. Interval value and forward the modified response message. [Claim 9] The network node according to claim 8, wherein the network node further comprises: a connectivity detection control module (503), configured to determine a request packet transceiver module (501)  After receiving the virtual circuit connectivity check request packet, the control request packet sending and receiving module (501) forwards the virtual circuit connectivity check request packet, and determines the response packet receiving and receiving. After the response packet received by the module (502) is not terminated at the local node, the control response packet transceiver module (502) modifies the survival time value in the response message and forwards the modified response message.  [Claim 10] A communication system, comprising: detecting an originating node and detecting a terminating node:  The detection initiation node sends a virtual circuit connectivity check request message to the detection termination node, where the virtual circuit connectivity check request message carries the hop count of the virtual pseudowire between the detection initiation node and the detection termination node, and Receiving a response packet sent by the detection termination node, and performing a virtual circuit connectivity check according to the survival time value in the response packet;  The detecting termination node receives the virtual circuit connectivity check request packet sent by the detection initiating node, and determines whether the received virtual circuit connectivity check request packet is terminated at the local node; if the received virtual circuit connectivity The check request message is terminated at the local node, and a response message is generated and sent to the detection initiating node, where the survival time value in the response message is set to the hop count of the virtual pseudowire. [Claim 11] The communication system according to claim 10, wherein the communication system further comprises detecting an intermediate node:  The detecting intermediate node receives the virtual circuit connectivity check request packet, and determines that the virtual circuit connectivity check request packet is not terminated at the local node, and the forwarding carries the hop of the virtual pseudowire between the detecting initiator node and the detecting termination node. The number of virtual circuit connectivity check request messages, the detection intermediate node does not modify the hop count of the virtual pseudowire between the detection initiation node and the detection termination node in the virtual circuit connectivity check request message. [Claim 12] The communication system according to claim 10 or 11, wherein the detection initiation node is a virtual pseudowire switching point provider edge device, and the detection termination node is a virtual pseudowire termination point provider edge device; Or, the detecting initiation node and the detection end The node nodes are virtual pseudowire termination point provider edge devices.