WO2009056034A1

WO2009056034A1 - Method, system and equipment to establish bfd detection for lsp tunnel

Info

Publication number: WO2009056034A1
Application number: PCT/CN2008/072768
Authority: WO
Inventors: Lin Dong; Changbao Liu; Shihai Hu; Xiaoting Cui
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-10-23
Filing date: 2008-10-21
Publication date: 2009-05-07
Also published as: CN101141330A; CN101141330B

Abstract

A BFD test method for LSP Tunnel with the spurious line series is provided. The method includes following steps as the source backbone network's edge PE equipment and the sink PE equipment are a group of PW which chooses the same couple of LSP Tunnel. The PW group is provided with the same Group ID; the source PE equipment creates the BFD conversation on LSP Tunnel and sends MPLS Ping message to the sink PE equipment via LSP Tunnel. The MPLS Ping message carries the Group ID and BFD specifications; the sink PE equipment chooses the reversal LSP Tunnel hereof as per the Group ID carried by MPLS Ping message, so as to send the BFD protocol message to the source PE equipment. Thus, BFD test can be established for LSP Tunnel. In this case, BFD test for the PW group can be reflected via BFD test on LSP Tunnel.

Description

Method, system and device for establishing BFD detection for LSP tunnel

The present invention relates to the field of network communications, and in particular, to a method, system, and device for establishing BFD detection for an LSP tunnel carrying a pseudowire group. Background technique

Due to the high bandwidth and low cost of Ethernet technology, operators are increasingly considering the use of Ethernet technology when setting up access networks, metropolitan area networks and even WANs; Carrier Ethernet has been More and more operators are recognized.

With the development of communication technology, the rapid detection of communication faults between adjacent systems, the establishment of alternative channels or the switching to other links in the event of a failure becomes an important problem to be solved. At present, many hardware or software can not provide this function, such as Ethernet, and some can not achieve path detection, such as forwarding engine or interface, can not achieve end-to-end detection. BFD (Bidirectional Forwarding Detection) is a fast detection mechanism. It is gradually developed from the basic transmission technology. It can detect faults in various layers of the network. BFD can be used to detect multiple types of transmissions, such as Ethernet, Multi-Protocol Label Switching (MPLS) paths, common routing encapsulation, and IPSec tunnels. BFD can also quickly detect connectivity status with neighboring nodes. Fault detection on any type of channel between systems. These channels include direct physical links, virtual circuits, tunnels, and MPLS (Multiprotocol Label Switch) LSPs ( Label Switch Path). , label switched paths), multi-hop routing channels, and indirect channels.

BFD is similar to the "Hello" protocol. It can detect the fault between two nodes in a short time. After a BFD session is established, the two nodes of the BFD session periodically send BFD reports to the other node. If the peer does not receive the BFD packet from the peer, the link is considered to be faulty.

An LSP is a path between MPLS nodes. An LSP can be regarded as a cross-section. One-way tunnel of the MPLS network. When detecting a link failure, the protection of the LSP can take two mechanisms, one is PS (Protection Switching) and the other is Rerouting. The PS is in the static protection mode, and the protection LSP is pre-established and allocated enough bandwidth to switch the use when the primary LSP link (node) fails, so as to minimize the packet loss delay caused by the LSP failure. Rerouting does not pre-establish a protection LSP. It only initiates the establishment of a protection LSP when the primary LSP link (node) fails. After the establishment is successful, the traffic is switched to the protection LSP. It can be seen that in general, when the LSP fails, the PS gravity route is reflected more quickly. The real-time performance of the protection switching needs to be ensured by a fast detection mechanism. The detection mechanism can be MPLS OAM detection or BFD detection.

The BFD session exchanges BFD specifiers through MPLS ping packets to automatically establish BFD sessions. The MPLS ping is similar to the ping of the IP. In the MPLS network, an MPLS packet called MPLS Echo Request can be sent. After the LSP is forwarded to the egress, the egress of the MPLS domain returns a BFD called MPLS Echo Reply. Negotiation can only be used, so that when reply is returned, you can know whether this LSP can be used for data forwarding correctly.

In the prior art, the BFD detection and protection of the PW group (PW1 and PW2) is implemented. The LSP1 and LSP3 are configured to carry the PW1 and PW2. The LSP1, the LSP2, the LSP3, and the LSP4 are the pair configured on the UPE1 and the NPE1. LSP protection group. You need to configure a pair of BFDs on the LSP protection group in the PW group. You need to configure a pair of BFDs on the LSP1 and LSP3. You need to specify local parameters, BFD specifiers, and peer BFD parameters and specifiers. When the BFD detects that the primary LSP is faulty, the LSP is triggered to protect the PW group.

In the process of implementing the embodiments of the present invention, the inventors have found that at least the following problems exist in the prior art: the prior art requires manual configuration to ensure that the PW group uses the same LSP, which has a large workload and a complicated configuration. After the LSP protection group that carries the PW group is configured, the BFD session cannot be automatically established on the LSP protection group that carries the PW group. You need to manually configure a pair of BFDs on the LSP protection group (LSP1 and LSP2). parameter, BFD specifier, and peer BFD parameters and specifiers. Summary of the invention

The embodiment of the invention provides a method, a system and a device for establishing a BFD detection for an LSP tunnel carrying a pseudowire group, so as to solve the problem of manual configuration of the PW group protection in the prior art, which has a large workload and a complicated configuration, and cannot automatically Establish defects in BFD protection.

An embodiment of the present invention provides a method for establishing a BFD test for an LSP tunnel carrying a pseudowire group, including:

The edge of the source backbone network PE device and the sink PE device selects the same pair of LSP tunnels for a group of PWs. The PW group is configured with the same group ID.

The source PE device creates a BFD session on the LSP tunnel, and initiates an MPLS ping packet to the sink PE device by using the LSP tunnel, where the MPLS ping packet carries the Group ID and the BFD specifier;

And the sinking PE device sends a BFD negotiation packet to the source PE device according to the group ID of the MPLS ping packet, and the BFD session of the LSP tunnel is established. .

The embodiment of the present invention further provides a system for establishing BFD detection for an LSP tunnel carrying a pseudowire group, including a source PE device and a sink PE device. Each PW in the PW group has the same source PE device and sink PE. Equipment,

The source PE device is configured to select the same pair of LSP tunnels for the PW group, and the PW group is configured with the same group ID; and the BFD session is created on the LSP tunnel, and the LSP tunnel is used to the sink PE. The device initiates an MPLS ping packet, where the MPLS ping packet carries the Group ID and the BFD specifier; the same Group ID

The sink PE device is configured to select a corresponding reverse LSP tunnel according to the Group ID carried in the MPLS ping packet sent by the source PE device, and send the reverse LSP tunnel to the source end on the reverse LSP tunnel. The PE device sends a BFD negotiation packet to establish BFD detection on the LSP that carries the PW.

The embodiment of the invention further provides a PE device, including a configuration module and an LSP tunnel. Select the module and the ping module,

The configuration module is configured to configure the same Group ID for a group of PW groups when establishing a pseudowire PW;

The LSP tunnel selection module is configured to allocate the same pair of LSP tunnels to the PW group according to the group ID configured by the configuration module;

The ping module is configured to send an MPLS ping packet to the PE device at the opposite end of the PW group according to the LSP tunnel selected by the LSP tunnel selection module, where the MPLS ping packet carries the Group ID and the BFD specifier; The MPLS ping packet sent by the peer PE device of the PW group is parsed, and the group ID carried in the MPLS ping packet is obtained.

Compared with the prior art, the embodiment of the present invention has the following advantages: In the embodiment of the present invention, a group of PWs are automatically carried on the same pair of LSP tunnels, and the group IDs are carried by the initiated MPLS ping packets. Automatically establishes BFD detection on a pair of LSPs that carry the PW group, thereby improving the automation level of establishing a BFD session on the LSP tunnel that carries the PW group, and performing BFD detection on the PW group by BFD detection on the LSP tunnel. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any inventive labor.

1 is a schematic diagram of a CE device accessing a VPLS through a VLL according to an embodiment of the present invention; FIG. 2 is a schematic diagram of a typical networking for establishing BFD detection for an LSP tunnel carrying a pseudowire group according to an embodiment of the present invention;

3 is a structural diagram of a PE device according to an embodiment of the present invention;

FIG. 4 is a flowchart of a method for detecting a BFD of a pseudowire group according to an embodiment of the present invention. detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

The schematic diagram shown in FIG. 1 is a specific application scenario of the embodiment of the present invention. MPLS L2VPN transparently transmits Layer 2 data of a user on an MPLS network. From the perspective of the user, the MPLS network is a Layer 2 switching network. Through the network, a Layer 2 connection is established between different sites. The principle of MPLS L2VPN is to use the label stack to transparently transmit user packets in the MPLS network. The outer label (called the tunnel label) is used to transfer packets from one PE to another. In MPLS L2VPN, it is called a VC label. It is used to distinguish different connections in different VPNs and connect to the edge of the user network. L2VPN is mainly divided into VLL (Virtual Leased Line) and VPLS (Virtual Private LAN Service). VLL is a simulation of traditional leased line services. By using IP networks to simulate leased lines, From the perspective of users at both ends of the virtual leased line, the virtual leased line approximates the past leased line. VPLS uses the IP public network to interconnect LANs through virtual private network segments, which is an extension of LANs on IP public networks. As shown in Figure 1, in an MPLS network, a PE router is the primary device. The PE is responsible for managing VPN users and establishing LSP connections between PEs. The CE distributes user network routes. The CE can be a router or a switch or a host. The VPLS technology uses the signaling protocol to establish a PW across the backbone network between the PEs. The PW can transmit the Ethernet data units on the backbone network. The PW is established by establishing a pair of unidirectional LSPs between the two PE endpoints. The established LSP tunnel can carry multiple VPLS services, and there are multiple LSPs between PEs. The PE can be layered into an NPE and a UPE according to the implementation function and the location in the network. The NPE and the UPE are exchanged through the MPLS LSP tunnel. VPLS technology use The signaling protocol establishes a PW (Peudo Wire) across the backbone network between the PEs. The PW can transmit the Ethernet data units on the backbone network. The PW establishes a pair of singles between the two PE endpoints. The established LSP tunnel can be used to carry multiple VPLS services. There are multiple LSPs between PEs.

However, the embodiment of the present invention is not limited to the application of the VLL access to the VPLS, and is applicable to the BFD detection and protection of the PW group in any scenario. As shown in FIG. 2, it is a set of network diagrams for detecting the BFD of the PW group in the embodiment of the present invention.

In the embodiment of the present invention, the same group ID is set for the PW group on the PE device at the source end of the PW group. In all the embodiments of the present invention, setting the same group ID for the PW group specifically includes: In this embodiment, the PW includes only PW1 and PW2, and the same Group ID is set to PW group for PW1 and PW2. Set the same group ID for the PW group to enable the source PE device to select the same LSP tunnel for the PW group with the same group ID, and pass the LDP (Label Distribute Protocol) between the source PE device and the sink PE device. The session can also enable the sink PE device to obtain the group ID of the PW group, that is, the PW group, so that the sink PE device also selects the same LSP tunnel for the same group of PWs on the sink PE. In addition, the BFD For MPLS LSPs scheme in the IETF (Internet Engineering Task Force) is used to add a Group ID to the MPLS ping packet to automatically establish a BFD session on the LSP that carries the PW group. .

The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings and embodiments.

In the networking diagram shown in FIG. 2, the system for establishing BFD detection for the LSP tunnel carrying the pseudowire group includes the source PE device and the sink PE device, and the PW in the pseudowire PW group according to the embodiment of the present invention is provided. The source PE device and the sink PE device of the PW are the same. For example, the source PE device and the sink PE device of PW1 and PW2 in the PW group are both UPE1 and NPE1. LSP2 and LSP4, and LSP1 and LSP3 are configured LSP protection groups. The embodiment of the present invention provides that the source PE device and the sink PE device are only for the sake of understanding. However, in practice, the PW is bidirectional, so a PE device may be a source PE device or a sink PE device. Therefore a PE set The functions of both the active end PE device and the sink PE device are also available. For example, in Figure 2, when CE1 traffic is accessed through MPLS L2VPN, PE1 can be considered as the source PE and PE2 is the sink PE. Similarly, when CE2 traffic is accessed through MPLS L2VPN, PE2 can be considered as the source PE. Equipment, PE1 is the sink PE device. The source PE device is configured to configure the same group ID for the same PW group as the source PE device and the sink PE device when the PW is established. For example, the PW group on the PE1 is set to be the same as the group. A group ID, in this embodiment, the PW is only PW1 and PW2, and the same group ID is set to the PW group for the PW1 and PW2. Similarly, on PE2, the PWs on PE2 are also grouped. The PWs on PE2 are classified into Group IDs as PW groups. The same pair of LSPs are allocated to the PW group according to the group ID. The peer PEs select the same LSP tunnel for the PW group with the same group ID. The source PE creates a BFD session on the LSP tunnel where the PW group resides. Waiting for the BFD negotiation packet, and initiating the MPLS ping packet to the sink PE device by using the LSP tunnel, the MPLS ping packet carrying the Group ID and the BFD specifier; and the sink PE device for using the source PE device The group LSP corresponding to the MPLS ping packet sent by the MPLS ping packet is sent to the source PE device to send a BFD negotiation packet, and the BFD session of the PW group is set up on the reverse LSP tunnel.

In order to facilitate the understanding of the embodiments of the present invention, the following describes the working process of the BFD detection system of the pseudowire group in the embodiment of the present invention, taking PE1 as the source PE and PE2 as the sink PE as an example. When a PW is set up, all the PWs between PE1 and PE2 are set up as one PW group. PW1 and PW2 are grouped into the same PW group. The same group ID is configured for the PW group. When an LSP tunnel is selected, only the LSP2 tunnel or the LSP4 tunnel is selected (because LSP2 and LSP4 are LSP protection groups); and PE1 can also know the group ID of the PW group through the LDP session. After the packet is sent, the corresponding reverse LSP tunnel is selected to feed back to PE1. If the LSP2 is connected to PE2 and the PW1 is carried, the PE2 will select the LSP1 tunnel to feed back to PE1. Therefore, the PW group can be automatically carried in the same pair of LSPs by setting the same group ID for the PW group. On the tunnel.

The embodiment of the present invention provides two ways of transmitting a group ID through an LDP session, as shown in the following figure.

VC letter

Control word VC type VC information length

Group ID

VCID

Interface parameter

One method is to directly configure the same group ID in the LDP session of the PW group. The other way is to set the group ID by setting the VC ID in the LDP session of the PW group. That is, the range of a VCID can be used to correspond to a group ID. Both of the above methods can achieve the purpose of transmitting the group ID.

PE1 creates a BFD session on the LSP2 tunnel, waits for BFD negotiation packets, and selects the LSP2 tunnel to send MPLS ping packets to the PE2 according to the configured group ID. PE1 adds BFD specifiers to the MPLS ping packets. Group ID of the corresponding PW group. After receiving the MPLS ping packet, the PE2 selects the LSP1 tunnel as the BFD reverse LSP tunnel according to the group ID in the MPLS ping packet, and sends a BFD negotiation packet to the PE1 through the LSP1, and returns the BFD negotiation report of the MPLS echo reply. The automatic creation of BFD on LSP1 and LSP2 is performed, and the two-way fast detection of LSP1 and LSP2 carrying the PW group is performed. In the embodiment of the present invention, the MPLS ping packet is extended by the TLV domain of the type length of the MPLS ping packet, and the MPLS ping packet extension is as follows:

01234567890123456789012345678901

+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+++++■+■+■ +■+■+■+■+■+■+■+

( Type ) PW GroupID Length ( 4 )

I Value |

+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+++++■+■+■ +■+■+■+■+■+■+■+ As shown in FIG. 3, it is a structural diagram of a PE device according to an embodiment of the present invention. The PE device can be used as a source PE device or a sink PE device. The PE device 1 includes a configuration module 11, an LSP tunnel selection module 12, and a ping module 13. The configuration module 11 is configured to configure the same group ID for the same PW group of the source PE device and the sink PE device when the PW group is established, so that the PW group is automatically carried on a pair of LSP tunnels. For example, the group ID of the same PW group of the source sink PE device is configured to be 100; or the range of one VC ID is specified as 100, so that all VC IDs in the range share a Group ID (100). The LSP tunnel selection module 12 is configured to allocate the same LSP tunnel to the PW group according to the group ID configured by the configuration module 11, as shown in FIG. 2, the PE1 is the PW group (PW1 and PW2), and the LSP2 is used as the LSP tunnel to carry the PW group, and the PE2 is The PW group (PW1 and PW2) selects LSP1 as the LSP tunnel to carry the above PW group.

The ping module 13 is configured to send an MPLS ping packet to the PE device at the peer end of the PW group according to the LSP tunnel selected by the LSP tunnel selection module 12, where the MPLS ping packet carries the Group ID and the BFD specifier, and is used as the peer end. The PE device is configured to parse the MPLS ping packet, and obtain the group ID carried in the MPLS ping packet.

The PE device 1 further includes a BFD module 15 for waiting for BFD session negotiation on the LSP tunnel, and selecting a corresponding reverse LSP tunnel according to the Group ID obtained by the ping module 13, and transmitting the BFD on the reverse LSP tunnel. The BPDU is negotiated to complete the automatic creation of the BFD on the pair of LSPs that carry the PW group.

The ping module 13 includes a ping packet sending sub-module 131 and a ping packet parsing sub-module 132. The ping packet sending sub-module 131 is configured to extend the MPLS ping packet and pass the MPLS Ping packet with the type length value TLV. The domain carries the group ID and the BFD specifier. The ping packet parsing sub-module 132 is configured to parse the MPLS ping packet on the sink PE to obtain the group ID and the BFD specifier.

The BFD detection system and the PE device of the pseudowire group in the embodiment of the present invention can automatically carry the PW group on a pair of LSP tunnels by setting the same group ID for the PW group, thereby improving the automation level and initiating the The MPLS ping packet carrying the group ID can automatically establish BFD detection on the pair of LSPs that carry the PW group. The BFD detection of the LSP tunnel reflects the BFD of the PW group. Detection,

As shown in FIG. 4, it is a flowchart of a BFD detection method for a pseudowire group according to an embodiment of the present invention. For convenience of description, the following steps are described in the networking diagram shown in FIG. 2, and PE1 is used as a source device, and ΡΕ2 For example, in the figure, PW1 and PW2 are the same PWs of the source device and the sink device, and both are UPE1 and NPE1. Therefore, PW1 and PW2 can be regarded as one PW group. LSP2 and LSP4, and LSP1 and LSP3 are configured LSP protection groups. This embodiment includes the following steps:

Step S401: When the source-side device establishes the pseudo-wire PW, configure the same group ID for the same PW group as the source-side sink device. For example, PE1 configures the same Group ID as 100 for PW1 and PW2. In this case, PE1 selects only the LSP2 tunnel or the LSP4 tunnel when the LSP tunnel is selected for PW1 or PW2 (because LSP2 and LSP4 are LSP protection groups).

In the step S402, the source PE device uses the LDP session to enable the sink PE device to know the group ID of the PW group. This step is not a necessary step, because the peer PE device can also configure the same group ID for the PW group. . After receiving the packet from the source PE device, the PE device selects the corresponding reverse LSP tunnel to feed back to PE1. For example, PE1 selects LSP2 to carry PW1 to PE2, and PE2. According to the Group ID carried in the LDP session, the LSP1 tunnel is selected to feed back to PE1. Therefore, the PW group can be automatically carried on a pair of LSP tunnels by setting the same Group ID for the PW group. The embodiment of the present invention provides two ways of transmitting a group ID through an LDP session, as shown in the following figure.

VC letter

Control word VC type VC information length

Group ID

VC ID

Interface parameter

One method is to directly configure the same group ID in the LDP session of the PW group. Another way is to set the VC ID in the LDP session of the PW group. Group ID, that is, a range in which a VCID can be used corresponds to a Group ID. The above two methods can achieve the purpose of delivering a Group ID.

Step S403: The source device and the sink PE device respectively allocate the same pair of LSP tunnels according to the group ID. When the source PE device allocates an LSP tunnel to the PW, it selects the corresponding LSP tunnel based on the group ID of the PW. For example, when PE1 selects an LSP tunnel for PW1, LSP2 is selected because the group ID of the PW1 is 100, and PE2 selects LSP1 according to the group ID. Similarly, PW1 and PW2 belong to one PW group, that is, PW1 and PW2. The same group ID, PE1 will also select LSP2 when selecting an LSP tunnel for PW2, and PE2 will also select LSP1.

Step S404: The source PE device creates a BFD session on the selected LSP tunnel, waits for the BFD negotiation packet, and sends an MPLS ping packet to the sink PE device. The MPLS ping packet carries the Group ID and the BFD specifier. For example, PE1 sends an MPLS ping request to the PE2 based on the configured LSP2 tunnel. The PE1 adds the BFD specifier and the group ID of the corresponding PW group to the MPLS ping packet. In the embodiment of the present invention, the MPLS ping packet is extended by the MPLS ping packet, and the MPLS ping packet is extended by the TLV domain of the MPLS ping packet. The MPLS ping packet extension is as follows:

01234567890123456789012345678901

1 ( Type ) PW GroupID | Length (4) | +■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■ +■+■+■+■+■+■+■+■+■+■+■+■+■+

I Value |

+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+■+++++■+■+■ +■+■+■+■+■+■+■+ Step S405: The sink PE device selects the corresponding reverse LSP tunnel to the source PE according to the Group ID carried in the MPLS ping packet sent by the source PE device. The device returns BFD negotiation packets to establish BFD detection for the PW group. For example, after receiving the MPLS ping packet, the PE2 selects the LSP1 tunnel as the BFD reverse LSP tunnel according to the group ID in the MPLS ping packet, and returns the BFD negotiation packet of the MPLS echo reply to the PE1 through the LSP1, thereby completing the LSP1. And BFD on LSP2 The two-way fast detection of LSP1 and LSP2 carrying the PW group is performed. Step S406: When the BFD detects that the LSP tunnel is faulty, the switchover of the LSP tunnel protection group is automatically triggered to implement detection and protection on the PW group. For example, if the LSP2 is faulty, the BFD session automatically triggers the switching of the LSP tunnel protection group and switches to LSP4 to carry the PW group to detect and protect the PW group.

According to the BFD detection method of the pseudowire group in the foregoing embodiment of the present invention, the PW group is automatically carried on the same pair of LSP tunnels by setting the same group ID for the PW group, thereby improving the automation level of the PW group carried by the LSP tunnel, and The BFD detection of the PW group is performed by the BFD detection of the LSP tunnel by the BFD detection of the LSP tunnel.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary general hardware platform, and of course, can also be through hardware, but in many cases, the former is a better implementation. the way. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a storage medium, including a plurality of instructions for making a A computer device (which may be a personal computer, server, or network device, etc.) performs the methods described in various embodiments of the present invention.

The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

Rights request

A method for establishing a BFD detection for an LSP tunnel carrying a pseudowire group, and the method includes the following steps:

The method for establishing a BFD for an LSP that carries a pseudowire group according to claim 1, wherein the PW group is configured with the same group ID, and the source and sink PE devices are The range of the VC IDs in the LDP session packets of the PW group is the same as the group ID of the LDP session.

The method for establishing BFD for the LSP tunnel carrying the pseudowire group according to claim 1, wherein the MPLS ping packet carrying the Group ID is implemented by the following steps:

The MPLS ping packet is extended, and the group ID is carried by the TLV domain of the type length of the MPLS ping packet.

The method of establishing BFD for the LSP tunnel carrying the pseudowire group according to claim 1, wherein after the BFD detection of the LSP tunnel is established, the method further includes:

When the BFD detects that the LSP is faulty, the switchover of the LSP tunnel protection group is automatically triggered to protect the PW group.

A system for establishing a BFD session for an LSP tunnel carrying a pseudowire group, which is characterized in that it includes a source PE device and a sink PE device, and each PW in the PW group has the same Source PE device and sink PE device,

The source PE device is configured to select the same pair of LSP tunnels for the PW group, and the PW group is configured with the same group ID; and the BFD session is created on the LSP tunnel, and the LSP tunnel is used to the sink PE. The device initiates an MPLS ping packet, where the MPLS ping packet carries the Group ID and the BFD specifier;

The system for establishing BFD for the LSP tunnel carrying the pseudowire group according to claim 5, wherein the source PE device includes a configuration module, an LSP tunnel selection module, a ping module, and a BFD module.

The configuration module is configured to configure the same group ID for the same PW group as the source end PE device when the PW is established;

The LSP tunnel selection module is configured to allocate the same LSP tunnel to the PW group according to the group ID configured by the configuration module.

The ping module is configured to send an MPLS ping packet to the sink PE device according to the LSP tunnel allocated by the LSP tunnel allocation module, where the MPLS ping packet carries the Group ID and the BFD specifier;

The BFD module is configured to wait for BFD session negotiation on the LSP tunnel.

The system for establishing BFD for the LSP tunnel carrying the pseudowire group according to claim 5, wherein the sink PE device includes a ping module, an LSP tunnel selection module, and a BFD module.

The ping module is configured to parse the MPLS ping packet sent by the source PE device, and obtain the group ID carried in the MPLS ping packet;

The LSP tunnel selection module is used by the sink PE to select a corresponding reverse LSP tunnel for the PW group according to the Group ID when creating a PW group;

The BFD module is configured to select a corresponding reverse LSP tunnel according to the group ID obtained by the ping module, and send a BFD negotiation report on the reverse LSP tunnel. Text.

A PE device, comprising: a configuration module, an LSP tunnel selection module, and a ping module,

The PE device of claim 8, further comprising a BFD module, configured to negotiate a BFD session on the LSP tunnel.

The PE device according to claim 8, wherein the ping module includes a ping packet sending submodule and a ping packet parsing submodule,

The ping packet sending submodule is configured to extend the MPLS ping packet, and carry the group ID by using a TLV domain of the type length value of the MPLS ping packet;

The ping packet parsing sub-module is configured to parse the MPLS ping packet, and is used to obtain the group ID and the BFD specifier in the packet.