WO2012028029A1

WO2012028029A1 - Switching method and system

Info

Publication number: WO2012028029A1
Application number: PCT/CN2011/076671
Authority: WO
Inventors: 彭少富
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-09-02
Filing date: 2011-06-30
Publication date: 2012-03-08
Also published as: CN101931520B; CN101931520A

Abstract

The present invention discloses a switching method and system. The method comprises the following steps: a dual-homing provider edge (PE) sends a "redundant Pseudo-Wire (PW) transmit-receive defect" message to a remote PE when a dual-homing customer edge (CE) or the dual-homing PE confirms a primary link failure, or the dual-homing PE announces a "link transmit-receive defect" message to the dual-homing CE when the dual-homing PE or the remote PE confirms a primary PW failure; the remote PE switches the traffic from the primary PW to a spare PW for transmission; the dual-homing CE switches the traffic from the primary link to a spare link for transmission. The present invention also provides a switching system. According to the technical solution of the present invention, when the link of the dual-homing CE is in failure, the links and PWs of the dual-homing CEs are rapidly switched without influence on the traffic of single-homing CEs.

Description

Switching method and system

The invention relates to multi-tag protocol exchange in the field of data communication (MPLS, Multi-Protocol

Label Switching ) Layer 2 Virtual Private Network (L2VPN) technology, in particular, relates to a handover method and system. Background technique

The protocol specifications related to MPLS L2VPN are being widely discussed and developed, and it has become the best choice for telecom operators to build virtual private networks (VPNs). The outstanding technical features of L2VPN are: It supports the interworking of multiple link emulation services and multiple Layer 2 link technologies, and is compatible with traditional Layer 2 VPN technologies. There are two main models of MPLS L2VPN: VPWS (Virtual Private Wire Service) and Virtual Private LAN Service (VPLS). The former is a pair of client devices (CE, Customer Edge). The logical link of the layer is interconnected, the latter is the interconnection of multiple CEs through an Ethernet LAN; the interconnection of the two models needs to involve multiple service provider devices in the Packet Switched Network (PSN). A PW (Pseudo-Wire) is set up between the PE and the Provider Edge. The PW is used to carry Layer 2 service traffic of the CE.

The PW itself needs to be carried on the public network tunnel of the PSN. The Fast Re-Route (FRR) technology provided by the public network tunnel is used to protect the traffic of the PW. That is, when the public network tunnel detects that the current active path fails. The traffic will be quickly switched to the protection path, but the PW will not perceive the switch. However, in the following cases, the PW must implement the protection of the service traffic through its own redundancy, that is, create a primary and a backup PW to form redundancy protection, including: CE dual-homed to two PEs, multi-segment pseudo Multi-terminal unit switching in the network (MS-PW, Multi-Segment Pseudowire) and hierarchical VPLS (H-VPLS, Hierarchical VPLS) networking (MTU-s, Multi-Tenant Unit Switch) is dual-homed to two PEs (PE-Routing and Bridging) with routing and switching capabilities.

In the prior art, for the VPWS model, the Internet Engineering Task Force (IETF, Internet Engineering Task Force) edge-to-edge simulation (PWE3, Pseudo-Wire Emulation Edge to Edge) working group has a relatively mature draft to discuss PW redundancy. Processing. However, for the VPLS model, the draft discussion related to the IETF L2VPN working group is not yet mature.

Figure 1 is a schematic diagram of the structure of a VPLS network in the prior art. As shown in Figure 1, a typical VPLS network has both a dual-homed CE and a single-homed CE. For example, CE3 is dual-homed to PE2 and PE3. The CE4 is singly assigned to the PE2. For the CE3, the PE2 and the PE3 are selected. For example, the CE can be configured to run the Spanning Tree Protocol (STP) on the CE3 to prevent the traffic between the PE and the CE from forming a loop. The PE connected to the link that is not blocked will become the active forwarding node. The CE can also be configured to set the primary and backup links on the CE3. When the primary link is detected or the PE connected to the primary link fails. Perform the switchover of the active and standby links, and configure the PE that is connected to the standby link as the active forwarding node. The PE determines the mode to run an election algorithm on the PEs of the corresponding VPLS network. One of the two PEs is elected as an active forwarding node.

There is no draft on the CE decision method in the prior art. Only a draft based on the Border Gateway Protocol (BGP) is discussed for the PE decision mode. The draft requirements for the carrier equipment are too high, and BGP routing is required. Both the advertised party and the BGP route reflector support the advertisement of the network layer reachability information (NLRI) in the VPLS network. All PEs in the VPLS network determine the active forwarding node through a specific data forwarding selection algorithm. . This method is difficult to implement for carrier devices that can only create PW redundancy through the Label Distribution Protocol (LDP). In addition, the existing data flow triggers the source MAC address learning, that is, generates a destination MAC address entry according to the address in the source MAC address entry in the received data flow, and the destination MAC address entry is the MAC address entry of the source MAC entry. However, in this process, it is not possible to distinguish whether the source MAC address entry is on the single-homed CE side or the dual-homed CE side, so that the generated destination MAC address entries inherit the PW FRR information indiscriminately; as shown in Figure 1, PE1 The destination MAC address entries of the CE3 and CE4 are inherited from the PW FRR information. As a result, the PW FRR switchover is bound to affect the traffic of the single-homed CE.

The type/length/value encapsulation format (TLV, Type Length Value) of the two types of media access control (MAC) defined by the existing protocol are included in the address recovery message of the LDP ( AWM, Address Withdraw Message ), where MAC List TLV is empty or non-empty. If the MAC address TLV is not empty, it indicates that the corresponding MAC address entry needs to be revoked in the VPLS network. As shown in Figure 1, PE2 can learn from AC3 after detecting that the access link (AC, Attachment Circuit) 3 is invalid. The MAC address entry to be sent can be included in the MAC List TLV and sent to PE1. PE1 will revoke the MAC address entry. When there are more MAC address entries, multiple messages need to be sent to cancel, so that service traffic converges slowly; If the TLV is empty, the corresponding VPLS network only needs to retain the MAC address entries learned on the PW that received the MAC List TLV, and revoke all other MAC address entries. As shown in Figure 1, PE2 detects the link. After the AC3 fails, if an empty MAC List TLV is sent to PE1, the MAC address entry learned from PW1 is maintained on PE1, so that the unicast service traffic that reaches CE3 continues to be forwarded from PW1. Obviously, no service traffic is switched. Service traffic is discarded when it reaches link AC3, and traffic protection cannot be achieved.

In the prior art, when detecting the fault of the access link AC and notifying the fault to the PW peer, the dual-homing or single-homing attribute of the access link AC is not distinguished, which causes the PW peer to perform dual-homed traffic. Switching affects single-homed traffic that does not require handover. Summary of the invention

In view of the above, the main purpose of the present invention is to provide a handover method and system. When a link of a dual-homed CE fails, the link of the dual-homed CE is quickly performed without affecting the traffic of the single-homed CE. Switching of PW.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

The present invention provides a handover method, including:

When the dual-homed client device (CE) or the dual-homed provider device (PE) determines that the primary link fails, the dual-homed PE sends a "redundant PW transceiver defect" message to the remote PE; or, when the dual-homed PE or When the remote PE determines that the primary PW fails, the dual-homed PE notifies the dual-homed CE of the "link transmission and reception defect" message;

The remote PE switches traffic from the primary pseudowire (PW) to the standby PW, and the dual-homed CE switches traffic from the primary link to the standby link for transmission.

In the above method, when the dual-homed CE or the dual-homed PE determines that the primary link fails, the dual-homed PE sends a message of "redundant PW transmission and reception defect" to the remote PE:

When the dual-homed CE detects that the primary link fails, it notifies the dual-homed PE "link transmission and reception defect" connected thereto; or, the dual-homed PE detects that the primary link is invalid, and sends a "link transmission and reception defect" message to the primary link. a dual-homed CE, or a "link receiving and receiving defect" message sent by a dual-homed CE connected thereto;

When the dual-homed PE determines that the primary link fails and determines that the failed primary link has a PW associated with it, the dual-homed PE sends a message of "redundant PW transmission and reception defect" to the remote PE.

In the above method, the method further includes: before the dual-homed PE or the dual-homed PE determines that the primary link is inactive, before the dual-homed PE sends a message to the remote PE, the method further includes:

The primary and backup links of the dual-homed CE are configured, and the primary PW and the standby PW are configured between the remote PE and the dual-homed PE, and the configured PW is associated with the primary and backup links of the dual-homed CE. In the above method, the primary link and the backup link of the dual-homed CE are configured to: configure two links on the dual-homed CE, set the redundancy status of one link as the primary, and the other link. The redundancy status is set to standby. The dual-homed CE generates AC Fast Reroute (FRR) forwarding entries based on the configured primary and backup links.

In the above method, the configuration of the primary PW and the standby PW between the remote PE and the dual-homed PE is as follows: multiple PWs are configured on the remote PE, and the remote PE passes through the configured PW and each adjacent one.

The PE is connected, and the redundancy status of one PW is set to be the primary, and the redundancy status of the other PW is set to standby; the primary PW and the standby PW are associated with the primary link and the standby link; and the remote PE is configured according to the primary The PW and the standby PW generate PW FRR forwarding entries.

In the above method, the configured PW is associated with the primary link and the standby link of the dual-homed CE:

Associate the primary PW and the standby PW between the remote PE and the dual-homed PE to the primary and backup links of the dual-homed CE. If the link between the dual-homed PE and the single-homed CE is configured, the link does not match. The primary PW is associated with the standby PW, and the remote PE distinguishes the single-homed traffic and the dual-homed traffic according to whether the association process is performed.

In the above method, the remote PE distinguishes the single-homed traffic and the dual-homed traffic according to whether the association process is performed:

The dual-homed PE will advertise the MAC address entry learned from the link of the dual-homed CE to the remote PE through the LDP address message. The remote PE inherits the MAC entry from the MAC address entry to the PW FRR entry. The forwarding behavior of the entry will be affected by the PW FRR. The MAC entry directs the remote PE to forward the dual-homed traffic.

The dual-homed PE does not advertise the MAC entry learned from the link of the single-homed CE to the remote PE. The remote PE does not inherit the PW FRR entry based on the MAC entry. The forwarding behavior of the MAC entry is not affected by the PW. Impact of FRR. This MAC entry guides the remote PE to forward single-homed traffic.

In the above method, the method further includes: When the dual-homed CE and the dual-homed PE determine that the primary link is valid, the dual-homed PE advertises the message "Redundant PW is received and received normally" to the remote PE; the dual-homed CE switches the traffic back to the primary link for transmission. The PE switches back the traffic to the primary PW for transmission.

In the above method, the method further includes:

When the dual-homed PE and the remote PE determines that the primary PW is valid, the dual-homed PE advertises the message "link is received and received normally" to the dual-homed CE; the dual-homed CE switches the traffic back to the primary link for transmission, and the remote PE will The traffic is switched back to the primary PW for transmission.

The present invention further provides a handover system, the system comprising: a dual-homed PE, a dual-homed CE, and a remote PE;

a dual-homed PE, used for dual-homing CE or self-determined when the primary link fails, sending a message of "redundant PW transmission and reception defect" to the remote PE;

The dual-homing CE is configured to switch traffic from the primary link to the standby link for transmission when determining that the primary link fails;

The remote PE, when used for the message "Redundant PW sends and receives defects", transfers traffic from the primary PW to the standby PW for transmission.

In the above system,

The system further includes: a configuration module, configured to configure a primary link and a backup link of the dual-homed CE, and configure a primary PW and a standby PW between the remote PE and the dual-homed PE, and configure the PW and the dual-homed CE The primary link is associated with the alternate link;

The dual-homed PE is further configured to: when the dual-homed CE or the self-determination primary link is restored, notify the remote PE of the message that the “redundant PW is sent and received normally”;

The dual-homing CE is further configured to: when determining that the primary link is valid, the traffic is switched back to the primary link for transmission;

The remote PE is further configured to: when receiving the message that the “redundant PW is sent and received normally”, the traffic is switched back to the primary PW for transmission. The present invention further provides a handover system, including: a dual-homed PE, a dual-homed CE, and a remote PE;

The dual-homed PE is used to notify the dual-homed CE of the "link receiving and receiving defect" message when the self-respecting PE determines that the primary PW is invalid;

When the dual-homing CE is used to receive the message of the link receiving and receiving defects, the traffic is switched from the primary link to the standby link for transmission;

The remote PE is used to determine that the primary PW fails, and the traffic is switched from the primary PW to the standby PW for transmission.

In the above system,

The dual-homed PE is further configured to notify the dual-homed CE of the "link transmission and reception normal" message when the remote PE determines that the primary PW is valid.

The dual-homing CE is further configured to: when receiving the message that the link is sent and received normally, the traffic is switched back to the primary link for transmission;

The remote PE is further configured to: when the primary PW is restored, the traffic is switched back to the primary PW for transmission.

The switching method and system provided by the present invention have PW redundancy and link redundancy. If the primary link fails, the traffic is quickly switched to the standby link and the standby PW for transmission, thereby realizing the link and PW in the VPLS network. The redundancy protection and the fast convergence of the traffic. When the dual-homed CE or the dual-homed PE determines that the primary link is invalid, the dual-homed PE sends a message to the remote PE. Therefore, the dual-homed PE does not send the relevant one that carries the single-homed CE. The destination MAC address entry is forwarded to the remote PE, and the traffic of the single-homed CE is not switched. Therefore, when the link of the dual-homed CE fails, the dual-homed CE chain can be quickly performed without affecting the traffic of the single-homed CE. Road and PW In addition, if the primary link is restored, the traffic can be switched back. In summary, the present invention better solves the problem of switching and switching back the traffic of the VPLS network. DRAWINGS

1 is a schematic structural diagram of a VPLS networking in the prior art;

2 is a schematic flow chart of a first embodiment of implementing a handover method according to the present invention;

3 is a schematic flowchart of a second embodiment of implementing a handover method according to the present invention;

4 is a schematic structural view of a handover system implemented by the present invention. detailed description

The basic idea of the present invention is: when the dual-homed client device (CE) or the dual-homed provider device (PE) determines that the primary link fails, the dual-homed PE sends a "redundant PW transceiving defect" message to the remote PE; Or, when the dual-homed PE or the remote PE determines that the primary PW fails, the dual-homed PE notifies the dual-homed CE of the "link receiving and receiving defect" message;

The remote PE switches traffic from the primary PW to the standby PW for transmission; the dual-homed CE switches traffic from the primary link to the standby link for transmission.

The invention will be further described in detail below with reference to the drawings and specific embodiments.

The present invention provides a handover method. FIG. 2 is a schematic flowchart of a first embodiment of a handover method according to the present invention. As shown in FIG. 2, the method includes the following steps:

Step 201: Configure a primary link and a backup link of the dual-homed CE.

Specifically, two links are configured on the dual-homed CE, and the redundancy state of one of the links is set to be the primary link, that is, the link is the primary link; and the redundancy state of the other link is set to the standby, that is, The link is a backup link and is used to protect the primary link. The setting principle can be to specify any one of them; only one of the primary link and the standby link can send and receive traffic, and the link that can send and receive traffic is doubled. The PE that is connected to the CE is an active forwarding node. The step may further include: the dual-homing CE generates an AC FRR forwarding entry according to the configured primary link and the standby link, and the forwarding entry is to be His service forwarding entries (such as MAC address entries) are inherited.

For example, the method is applied to the VPLS network of Figure 1. The method for configuring the primary link AC3 and the standby link AC4 of the dual-homed CE3 is as follows: As shown in Figure 1, the access link AC3 of the CE3 is configured on the PE2. Configure the access link AC5 of CE4, configure the access link AC4 of CE3 on PE3, and set the redundancy state of the access link AC3 of CE3 to PE2 as the primary. That is, the access link AC3 is the master of CE3. Link; the redundancy state of the access link AC4 that connects CE3 to PE3 is set to standby, that is, the access link AC4 serves as the backup link of CE3, and is used to protect the primary link AC3;

The CE3 generates an AC FRR forwarding entry based on the configured primary link AC3 and the standby link AC4. The primary link entry and the backup link entry include the outbound port AC3 and the outbound port AC4. Source MAC address learning, that is, the source MAC address of the traffic received by the CE3 (incoming port AC3), the destination MAC address entry (AC3) entry, and the destination MAC address entry as the service forwarding entry of the traffic. The generated destination MAC address entry inherits the AC FRR forwarding entry, so that the egress port of the generated destination MAC address entry is not only AC3 but also AC4. Similarly, if CE3 receives traffic from the alternate link AC4, source MAC learning is performed. That is, according to the source MAC address of the traffic received by CE3 (incoming port AC4), the destination MAC address (outbound port AC4) entry is generated, and the destination MAC address entry is used as the service forwarding entry of the traffic, and the generated destination MAC address entry inherits the AC. The FRR forwards the entry so that the egress port of the generated destination MAC address entry is not only AC4 but also AC3. Therefore, when the primary link AC3 is valid, CE3 receives the entry. The traffic is sent by the primary link AC3 by default. The inheritance means that there is only one outgoing port in the destination MAC address entry. Because there are two links in the AC FRR forwarding entry, the primary link and the backup link exist. After inheriting the AC FRR forwarding entry, there are two outgoing ports in the destination MAC address entry.

Step 202: Configure a primary PW and a standby PW between the remote PE and the dual-homed PE, and associate the configured PW with the primary link and the standby link of the dual-homed CE.

Specifically, multiple PWs are configured on the remote PE, and the remote PE passes the configured PW. Each PE of the neighbor is connected, and the redundancy status of one of the PWs is set to be the primary PW, and the redundancy status of the other PW is set to standby, that is, as the standby PW, which is used to protect the primary PW; It is specified that any one of them is primary, but must be consistent with the primary link AC and the standby link AC; the remote PE can switch traffic between the primary PW and the standby PW;

The step may further include: associating the primary PW and the standby PW with the primary link and the standby link of the dual-homed CE, if the link AC between the dual-homed PE and the single-homed CE is configured, the link AC does not The PW of the dual-homed PE is associated, and the remote PE distinguishes the single-homed traffic and the dual-homed traffic according to whether the association process is performed. The remote PE generates a PW FRR forwarding entry according to the configured primary PW and the standby PW. The entry will be inherited by the other service forwarding entry (for example, the MAC address entry); the dual-homed PE will advertise the MAC address learned from the link AC of the dual-homed CE to the remote PE through the LDP address message. The remote PE then forwards the MAC entries to the PW FRR entries, so that the forwarding behavior of the MAC entries is affected by the PW FRR. The MAC entries guide the remote PEs to forward the dual-homed traffic. This is called The dual-homed PE does not advertise the MAC entry learned from the connected AC of the single-homed CE to the remote PE. Therefore, the remote PE cannot inherit these MAC entries to the PW. FRR form So that these acts of MAC forwarding entries from PW FRR influence, which is not affected by PW FRR of the MAC forwarding table entries for the guidance of the remote PE single-homed traffic, which is the so-called single-homed traffic.

For example, the method is applied to the VPLS network of FIG. 1. PE2 and PE3 are dual-homed PEs. The method for establishing a primary PW and a standby PW between PE1, PE2, and PE3 is as follows: PW1 is created and connected to the neighboring PE2 through PW1. The link AC3 between PE2 and CE3 is the primary link AC. To maintain consistency, the redundancy status of PW1 is set to be the primary, that is, PW1 is the primary PW. Create PW2 on PE1 and connect it to the neighboring PE3 through PW2. The link AC4 between PE3 and CE3 is the standby link AC. To maintain consistency, set the redundancy status of PW2 to standby, that is, PW2 as the standby PW. For protecting the main PW; PE1 A PW FRR forwarding entry is generated based on the configured primary PW1 and the standby PW2. The forwarding entry is inherited by other service forwarding entries (such as MAC address entries). PW1 is created on PE2 and connected to the adjacent PE1 through PW1. The PW1 created on PE2 has no redundant PW. The redundancy status of the PW1 is the default. The primary link AC3 associated with PW1 is configured on PE2. You can also configure multiple associated links AC to form an associated link. The AC group is created on the PE3. The PW2 is connected to the PE1 of the PE4. The PW2 is connected to the PW2 on the PE3. The standby link AC4 associated with the PW2 is configured on the PE3. Associated links AC form an associated link AC group.

If the traffic received by the PE2 is from the primary link AC3, the source MAC address learning is performed to obtain the destination MAC address entry. The PE2 determines that the primary link AC3 is associated with PW1 according to the configured primary link AC3 associated with PW1. PE2 needs to be obtained. The destination MAC address entry is sent to the PE1 through the LDP address message, and is used to inform the PE1 that the destination MAC address entry needs to inherit the PW FRR forwarding entry. In this embodiment, the LDP address message carrying the destination MAC address entry is a redundant PW. If the received traffic is from the link AC5, the PE2 performs the source MAC address learning, but the link AC5 is not associated with any PW, and the LDP address message is not sent to the PE1. If the source MAC address is learned from the standby link AC4, the destination MAC address entry is obtained. After the standby link AC4 is associated with the PW2, the destination MAC address entry sent by the PE3 is sent to the PE1 through the LDP address message to notify the PE1. The destination MAC address entry needs to inherit the PW FRR forwarding entry.

If the traffic received by PE1 is from PW1, the source MAC address is learned and the destination MAC address entry is obtained. The default outgoing port of the destination MAC address entry is PW1. When PE1 receives the PW1 from PE2, it needs to inherit the PW FRR forwarding entry. When the destination MAC address entry is used, PE1 maintains the destination MAC address entry and allows the destination MAC address entry to inherit the PW FRR forwarding entry, so that it no longer only forwards traffic according to the outgoing port PW1, but based on the inherited PW. The FRR forwards the entry to forward traffic. The outgoing port is PW1 and PW2. If the traffic received by PE1 is from PW2, the source MAC address is learned and the destination MAC address entry is obtained. The default outgoing port of the destination MAC address entry is PW2. When PE1 receives the PW2 from PE3, it needs to inherit PW FRR. When the destination MAC address entry is published, PE1 maintains the destination MAC address entry and allows the destination MAC address entry to inherit the PW FRR forwarding entry, so that it no longer only forwards traffic according to the outgoing port PW2, but obtains the inheritance according to the inheritance. The PW FRR forwarding entry is used to forward traffic, and the outgoing egress port includes PW1 and PW2. The inheritance means that there is only one egress port in the destination MAC address entry, because there are two main PWs and two standby PWs in the PW FRR forwarding entry. Link, so after it inherits the PW FRR forwarding entry, there are two outgoing ports in the destination MAC address entry.

With this method, PE 1 determines the destination MAC address entry that needs to inherit the PW FRR forwarding entry based on the destination MAC address entry in the LDP address message. Therefore, not all destination MAC address entries inherit PW FRR. The incoming traffic comes from link AC5. In this case, the obtained destination MAC address entry does not inherit PW FRR; therefore, when traffic is switched and switched back between the primary link and the standby link or between the primary PW and the standby PW The traffic between the single-homed CE and the PE is not affected. Therefore, the traffic between the dual-homed CE and the PE is protected, and the traffic between the single-homed CE and the PE is normally transmitted.

Step 203: When the dual-homed CE or the dual-homed PE determines that the primary link fails, the dual-homed PE sends a message of “redundant PW transmission and reception defect” to the remote PE.

Specifically, the dual-homed CE (such as CE3 in FIG. 1) can detect that the primary link fails or receives the "link receiving and receiving defect" message sent by the dual-homed PE (such as PE2 in FIG. 1) connected thereto; The detection mode can be that the physical link of the primary link is set to DOWN or the physical failure caused by the deletion. The dual-homed CE can automatically detect the failure of the primary link. If the CE detects that the primary link is invalid, the CE needs to send the fault. The link sends and receives a defect message to the dual-homed PE connected thereto; or, the dual-homed PE detects that the primary link is invalid, or receives a dual-homed CE transmission connected thereto The "link is sent and received"message; the detection mode may be: the physical failure of the physical interface where the dual-homed PE is deleted, the dual-homed PE can automatically detect the failure of the primary link; The primary link fails, and the dual-homed PE also needs to send a "link transmission and reception defect" message to the dual-homed CE connected thereto;

When the dual-homed PE determines that the primary link is invalid, it is determined that the failed primary link exists with the associated PW according to the related information generated when the primary link is associated with the primary PW, so the remote PE needs to be triggered. PE1 of 1 performs the switching between the primary PW and the standby PW; therefore, the dual-homed PE also needs to send a message of "redundant PW transmission and reception defect" to the remote end of the primary PW associated with the primary link, that is, the remote PE, where, and the PE When the access link AC of the connected dual-homed CE fails, the PE sends the message of the "redundant PW transmission and reception defect". If the access link AC of the single-homed CE connected to the PE fails, The message "Redundant PW Transceiver Defect" is not sent.

Step 204: The dual-homing CE switches the traffic from the primary link to the standby link for transmission, and the remote PE switches the traffic from the primary PW to the standby PW for transmission.

Specifically, when the dual-homing CE determines that the primary link is invalid, the dual-homing CE determines whether there is a backup link according to the AC FRR forwarding entry generated by itself, and determines whether the standby link is valid. The CE switches the traffic to the standby link for transmission. That is, the dual-homed CE stops sending traffic from the outbound ports of the two outgoing ports according to the two outbound ports in the destination MAC address entry generated by the dual-homed CE. Issued from another egress port; if it is determined that the alternate link is invalid, the destination MAC address entry that inherits the AC FRR forwarding entry becomes invalid, and the dual-homed CE stops sending traffic to the primary and backup links;

When the remote end of the dual-homed PE of the primary PW that is associated with the primary link, that is, the remote PE, determines that the message of the "redundant PW transmission and reception defect" is received, the remote PE determines that there is a standby PW according to the PW FRR forwarding entry generated by the remote PE. If the standby PW is valid, the remote PE switches the traffic to the standby PW for transmission; that is, the dual-homed PE stops the two outgoing ports according to the generated destination MAC address entry. The outbound end of the outgoing traffic in the outgoing port If the backup PW is invalid, the destination MAC address entry that inherits the PW FRR forwarding entry becomes invalid, and the remote PW stops sending traffic to the primary PW and the standby PW.

Step 205: When the dual-homed CE and the dual-homed PE determine that the primary link is restored, the dual-homed PE notifies the remote PE of the message that the redundant PW is sent and received normally.

Specifically, when the dual-homed CE (such as CE3 in FIG. 1) takes priority over the dual-homed PE to detect that the primary link is restored, the dual-homed CE determines that the primary link is restored, and sends a message that the link is sent and received normally. The dual-homed PE connected to the dual-homed PE receives the "link-received normal" message sent by the dual-homed CE (such as CE3 in Figure 1), and determines that the primary link is valid through detection. The PE determines that the primary link is valid. The detection mode of the dual-homed PE can be: The physical interface of the dual-homed PE is physically connected to the physical link. The detection mode of the dual-homed CE can be: the physical interface where the primary link resides. The physical validity of the link is set to UP or the link is added. The dual-homed CE can automatically detect that the primary link is valid.

Or, when the dual-homed PE (such as PE2 in FIG. 1) takes precedence over the dual-homed CE to detect that the primary link is restored, sending a "link-received normal" message to the dual-homed CE connected thereto, when the dual-homed CE receives When the dual-homed PE (such as PE2 of FIG. 1) is connected to the "link transmission and reception normal" message, and the self-test determines that the primary link is valid, the dual-homing CE determines that the primary link is valid, and the dual-homed CE determines the primary. After the link is restored, the message that the "link is received and received normally" is sent to the dual-homed PE. At this time, the dual-homed PE detects that the primary link is valid and receives the "link transmission and reception normal" message of the dual-homed CE. Therefore, it is determined that the primary link recovery is valid;

After the dual-homing PE determines that the primary link is restored, the remote PE is triggered to perform the switchback of the standby PW and the primary PW. That is, the dual-homed PE (such as PE2 in FIG. 1) notifies the opposite end of the primary PW associated with the primary link. The remote PE (PE1 in Figure 1) sends a message "Redundant PW Transceiver Normal".

In this embodiment, the dual-homed PE can determine whether the primary link is valid according to the status of the physical port. The dual-homed CE can only determine whether the primary link is valid according to the status of the physical port. Both the dual-homed PE and the dual-homed CE cannot determine whether the primary link detected by the peer is valid. Therefore, both the dual-homed PE and the dual-homed CE need to determine that the primary link is valid.

Step 206: The dual-homing CE reverts the traffic to the primary link for transmission, and the remote PE returns the traffic to the primary PW for transmission.

Specifically, when the dual-homing determines that the primary link is valid, or receives the message that the link is sent and received normally sent by the dual-homed PE, the dual-homed CE sends a message that the link is sent and received normally to the dual-homed PE, when dual-homing When the CE sends a message to the dual-homed PE "link is received and received normally" and also receives the "link-received normal" message of the dual-homed PE, the dual-homed CE cuts the traffic from the standby link back to the primary link;

When the peer end of the dual-homed PE of the primary PW associated with the primary link, that is, the remote PE (such as PE1 in Figure 1) receives the message "Redundant PW is received and received normally", the remote PE sends "redundant" to the dual-homed PE. If the remote PE not only informs the dual-homed PE of the "redundant PW transmission and reception" message, but also receives the "redundant PW transmission and reception normal" message of the dual-homed PE, the remote PE will send traffic. Switch back to the primary PW for transmission.

The remote PE or the dual-homed CE can implement the timely switchback or the delay switchback based on the normal mode of the two-way acknowledgement. When the delay switchback is required, the normal message can be sent or passively acknowledged for a period of time. Note that the dual-homed PE is between the remote PE and the dual-homed CE. When the dual-homed PE sends or passively responds to the normal message on either side, the other party must ensure that the other side is normal.

In the above method, the "redundant PW transmission and reception defect" and the "redundant PW transmission and reception normal" message pair are determined by the PE according to its own role. For the remote PE, if it belongs to the VPLS instance and is in the instance, If the PW is in the FRR, the corresponding PW needs to introduce the message pair. For the dual-homed PE, if the PW belongs to the VPLS instance and the PW in the instance is associated with the AC, the corresponding PW needs to introduce the message pair.

3 is a schematic flowchart of a second embodiment of a handover method according to the present invention, as shown in FIG. 3, The method includes the following steps:

Step 301: Configure a primary link and a backup link of the dual-homed CE.

Step 302: Configure a primary PW and a standby PW between the remote PE and the dual-homed PE.

Steps 301 and 302 are detailed in steps 201 and 203.

Step 303: When the dual-homed PE or the remote PE determines that the primary PW is invalid, the dual-homed PE notifies the dual-homed CE of the "link receiving and receiving defect" message;

Specifically, if the primary PW fails before the primary link, the dual-homed PE (such as PE2 in FIG. 1) can detect that the primary PW is invalid, or receives the remote PE connected to it (such as PE1 in FIG. 1). "Redundant PW Transceiver Defect" message, in which the PE detects the PW failure detection mode, the PE detects that the outer tunnel carrying the PW is unreachable, or the PW itself fails to keep alive, or the TP-OAM detects the PW failure, or the BFD detects The PW fails. If the dual-homed PE detects the failure of the primary PW, the dual-homed PE also needs to send a message of "redundant PW transmission and reception defect" to the remote PE, which is equivalent to the remote PE also determining that the primary PW is invalid. Similarly, other pairs The processing method of the home PE (such as PE3 in Figure 1) is the same as above; or, the remote PE detects the failure of the primary PW, or receives the message of "redundant PW transmission and reception defect" sent by the dual-homed PW connected thereto; The PE detects that the primary PW is invalid. The remote PE also needs to send a message of "redundant PW transmission and reception defect" to the dual-homed PE connected to it. The dual-homed PE also determines that the primary PW is invalid.

When the dual-homed PE determines that the primary PW is invalid, it is determined that the primary PW that is in the default is associated with the primary link according to the related information generated when the primary link is associated with the primary PW, so the dual-homed CE needs to be triggered to perform the primary link. The switch to the standby link; the dual-homed PE also needs to send a "link send and receive defect" message to the peer dual-homed CE of the primary link associated with the primary PW (such as CE3 in Figure 1).

Step 304: The dual-homing CE switches the traffic from the primary link to the standby link for transmission, and the remote PE switches the traffic from the primary PW to the standby PW for transmission.

Specifically, when the dual-homing CE receives the message of "link transmission and reception defect" sent by the dual-homing PE When the dual-homing CE determines that there is a backup link according to the AC FRR forwarding entry generated by itself, it determines whether the standby link is valid. If it is determined that the standby link is valid, the dual-homed CE switches the traffic to the standby link for transmission, that is, The dual-homed CE stops sending traffic from the egress port that is sending traffic from the two egress ports according to the two egress ports in the destination MAC address entry generated by itself, and sends traffic from another egress port; if the alternate link is determined If the entry is invalid, the destination MAC address entry that inherits the AC FRR forwarding entry becomes invalid. The dual-homed CE stops sending traffic to the primary link and the standby link.

When the remote P1 of the dual-homed PE of the primary PW that is associated with the primary link determines that the primary PW is invalid, the remote PE determines whether the standby PW is valid according to the PW FRR forwarding entry generated by the remote P-P. If it is determined that the standby PW is valid, the remote PE switches the traffic to the standby PW for transmission; that is, the dual-homed PE stops the outgoing traffic from the two outgoing ports according to the two outgoing ports in the destination MAC address entry generated by the dual-homed PE. The outbound port sends traffic, and the traffic is sent from the other egress port. If it is determined that the standby PW is invalid, the destination MAC address entry that inherits the PW FRR forwarding entry becomes invalid, and the remote PW stops sending traffic to the primary PW and the standby PW. .

Step 305: When the dual-homed PE and the remote PE determine that the primary PW is valid, the dual-homed PE notifies the dual-homed CE that the "link is received and received normally" message;

Specifically, when the dual-homed PE (such as PE2 in FIG. 1) takes precedence over the remote PE detecting that the primary PW is restored, the message "relay PW is received normally" is sent to the remote PE connected to it (such as PE1 in FIG. 1). The remote PE determines that the primary PW is valid when the remote PE receives the "redundant PW transmission and reception normal" message sent by the dual-homed PE connected to it, and the remote PE determines that the primary PW is valid; After the PW is restored, the message that the "redundant PW is sent and received normally" is sent to the dual-homed PE. At this time, the dual-homed PE detects that the primary PW is valid and receives the "redundant PW transmission and reception normal" message of the remote PE. Therefore, the dual-homing PE determines that the primary PW is valid. The detection mode of the PW that is detected by the PE is that the PE detects the opening of the outer tunnel that carries the PW. And the PW itself is effective;

Or, when the remote PE detects that the primary PW recovery is valid, the remote PE determines that the primary PW is valid, and sends a message that the "redundant PW is received and received normally" to the dual-homed PE. The dual-homed PE determines that the primary PW is valid when the primary PW is restored, and the dual-homed PE determines that the primary PW is valid, when the dual-homed PE determines that the primary PW is valid. The related information generated when the primary link is associated with the primary PW determines that the active primary PW has a primary link associated with the active primary PW, and triggers the dual-homed CE to perform the failback of the standby link and the primary link; that is, the dual-homed PE The message "Link is received and received normally" is sent to the peer dual-homed CE of the primary link associated with the primary PW (such as CE3 in Figure 1).

Step 306: The dual-homing CE reverts the traffic to the primary link for transmission, and the remote PE returns the traffic to the primary PW for transmission.

In this embodiment, the default link and the standby link are always valid. Therefore, when the dual-homed CE receives the message that the link is sent and received normally, it determines that the primary PW is restored. Therefore, the traffic is switched back.

In order to achieve the above method, the present invention also provides a switching system, and FIG. 4 is an implementation of the present invention. The structure of the system is changed. As shown in FIG. 4, the system includes: a dual-homing PE 41, a dual-homing CE 42, and a remote PE 43;

Dual-homed PE41, used for dual-homing CE 41 or self-determined when the primary link fails, sending a message of "redundant PW transmission and reception defect" to the remote PE 43;

The dual-homing CE42 is configured to switch traffic from the primary link to the standby link for transmission when determining that the primary link fails;

The remote PE43, when used for the message of "redundant PW transceiver defect", switches traffic from the primary PW to the standby PW for transmission.

The system also includes:

The configuration module 44 is configured to configure the primary link and the backup link of the dual-homed CE42, configure the primary PW and the standby PW between the remote PE 43 and the dual-homed PE 41, and configure the PW and the primary link of the dual-homed CE. Associated with the alternate link;

The dual-homing PE 41 is further configured to: when the dual-homing CE 42 or the self-determination primary link is restored, notify the remote PE 43 that the message “redundant PW is normal and received normally”;

The dual-homing CE 42 is further configured to: when the primary link is restored, the traffic is switched back to the primary link for transmission;

The remote PE 43 is further configured to: when receiving the message that the “redundant PW is sent and received normally”, the traffic is switched back to the primary PW for transmission.

The present invention further provides a switching system, as shown in FIG. 4, the system includes: a dual-homing PE 41, a dual-homing CE 42, and a remote PE 43;

The dual-homing PE 41 is configured to notify the dual-homing CE 42 of a "link receiving and receiving defect" message when the self- or remote-side PE determines that the primary PW fails;

The dual-homing CE42 is configured to switch traffic from the primary link to the standby link for receiving the message of "link transmission and reception defect";

The remote PE 43 is configured to switch the traffic from the primary PW to the standby PW when the primary PW fails. Transfer.

The system further includes: a configuration module 44, configured to configure a primary link and a backup link of the dual-homed CE 42, and configure a primary PW and a standby PW between the remote PE 43 and the dual-homed PE 41, and configure the PW and The primary link and the standby link of the dual-homed CE are associated;

The dual-homed PE 41 is further configured to notify the dual-homing CE 42 that the "link is transmitted and received normally" message when the remote PE 43 determines that the primary PW is valid.

The dual-homing CE 42 is further configured to: when receiving the message that the link is sent and received normally, the traffic is switched back to the primary link for transmission;

The remote PE 43 is further configured to: when the primary PW is restored, the traffic is switched back to the primary PW for transmission.

Based on the above two systems, the configuration module 44 configures the primary link and the backup link of the dual-homing CE 42 as:

Configure two links on the dual-homed CE42, set the redundancy status of one link as the primary, and set the redundancy status of the other link to standby. The dual-homed CE42 is configured according to the primary and backup links. Generate an AC FRR forwarding entry.

The configuration module 44 configures the primary PW and the standby PW of the dual-homed PE41 to be:

Configure multiple PWs on the remote PE43. The remote PEs are connected to each adjacent PE through the configured PW. The redundancy status of one PW is set to be the primary and the redundancy status of the other PW is set to standby. That is, as the standby PW; the primary PW and the standby PW are associated with the primary link and the standby link; and the remote PE 43 generates the PW FRR forwarding entry according to the configured primary PW and the standby PW.

Associating the configured PW with the primary link and the backup link of the dual-homed CE is as follows: associating the primary PW and the standby PW between the remote PE and the dual-homed PE to the primary link and the standby link of the dual-homed CE If the link between the dual-homed PE and the single-homed CE is configured, the link is not associated with the primary PW and the standby PW, and the remote PE distinguishes the single-homed traffic and the dual-homed traffic according to whether the association process is performed. When the dual-homing CE 42 or the dual-homing PE 41 determines that the primary link fails, the dual-homed PE 41 sends a message that the "redundant PW is sent and received defective" message to the remote PE 43 is:

When the dual-homing CE 42 detects that the primary link fails, it notifies the dual-homed PE 41 that it is connected with the "link transmission and reception defect"; or, the dual-homed PE 41 detects that the primary link is invalid, or is notified by the dual-homed CE 42 connected thereto Sending and receiving defects"; when the dual-homing PE41 detects the failure of the primary link, notifying the dual-homed CE42 "link transmission and reception defect" connected thereto; when the dual-homing PE41 determines that the primary link is invalid and determines that the failed primary link exists associated with it At PW, the dual-homed PE 41 sends a message "Redundant PW Transceiver Defect" to the remote PE 43.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included. Within the scope of protection of the present invention.

Claims

Claim

A switching method, characterized in that the method comprises:

When the dual-homed client device (CE) or the dual-homed provider device (PE) determines that the primary link fails, the dual-homed PE sends a message of "redundant PW transmission and reception defect" to the remote PE; or, when the dual-homed PE or When the remote PE determines that the primary pseudowire (PW) fails, the dual-homed PE notifies the dual-homed CE of the "link transmission and reception defect" message;

The remote PE switches traffic from the primary PW to the standby PW, and the dual-homed CE switches traffic from the primary link to the standby link for transmission.

The method according to claim 1, wherein when the dual-homed CE or the dual-homed PE determines that the primary link fails, the dual-homed PE sends a message of "redundant PW transmission and reception defect" to the remote PE. :

The method according to claim 1, wherein, when the dual-homed CE or the dual-homed PE determines that the primary link fails, the dual-homed PE sends a message to the remote PE, The method also includes:

Configure the primary and backup links of the dual-homed CE, and configure the primary PW and the standby PW between the remote PE and the dual-homed PE, and associate the configured PW with the primary and backup links of the dual-homed CE.

The method according to claim 3, wherein the primary link and the backup link configured with the dual-homed CE are: Configure two links on the dual-homed CE, set the redundancy status of one link as the primary, and set the redundancy status of the other link to standby. The dual-homed CE is configured according to the primary and backup links. Generate an AC Fast Reroute (FRR) forwarding entry.

The method according to claim 3, wherein the configuration of the primary PW and the standby PW between the remote PE and the dual-homed PE is:

Configure multiple PWs on the remote PE. The remote PEs are connected to each adjacent PE through the configured PW. The redundancy status of one PW is set to be the primary and the redundancy status of the other PW is set to standby. The primary PW and the standby PW are associated with the primary link and the standby PW. The remote PE generates a PW FRR forwarding entry according to the configured primary PW and the standby PW.

The method according to claim 3, wherein the associating the configured PW with the primary link and the standby link of the dual-homed CE is:

The method according to claim 5, wherein the remote PE distinguishes the single-homed traffic and the dual-homed traffic according to whether the association process is performed:

8. The method according to claim 1, wherein the method further comprises: When the dual-homed CE and the dual-homed PE determine that the primary link is valid, the dual-homed PE advertises the message "Redundant PW is received and received normally" to the remote PE; the dual-homed CE switches the traffic back to the primary link for transmission. The PE switches back the traffic to the primary PW for transmission.

The method according to claim 1, wherein the method further comprises: when the dual-homed PE determines that the primary PW is valid, the dual-homed PE advertises to the dual-homed CE that the link is normally received and received. The message is sent by the dual-homed CE to the primary link for transmission. The remote PE switches the traffic back to the primary PW for transmission.

A switching system, the system comprising: a dual-homed PE, a dual-homed CE, and a remote PE;

A dual-homed PE, used for the dual-homing CE or itself to determine that the primary link fails, sending a message of "redundant PW transmission and reception defect" to the remote PE;

The remote PE is used to switch traffic from the primary PW to the standby PW for transmission when receiving the message "Redundant PW Transceiver Defect".

11. The system of claim 10, wherein:

The system further includes: a configuration module, configured to configure a primary link and a backup link of the dual-homed CE, configure a primary PW and a standby PW between the remote PE and the dual-homed PE, and configure the PW and the dual-homed CE master The link is associated with the alternate link;

The remote PE is further configured to: when receiving the message that the “redundant PW is sent and received normally”, the traffic is switched back to the primary PW for transmission.

The dual-homed CE is configured to switch traffic from the primary link to the standby link for transmission when receiving a "link transmission and reception defect" message;

13. The system of claim 12, wherein