Method for synchronizing PW primary and backup ARP entries

Abstract

The present invention discloses a method for synchronizing PW master and backup ARP table entry information, comprising the following steps: establishing a dual-homing service network; customizing the format of an ARP table entry information synchronization message; issuing an ACL configuration plan to PE2, PE1, and PE3 devices, and establishing a forwarding path for the PW master and backup ARP table entry information synchronization message; if a CE1 device and a CE2 device transmit services through PE1 and PE2, the PE2 device is the active PE device and the PE3 device is the inactive PE device; the active PE device periodically receives a packaging signal, packages its own ARP table entry information, and forms an ARP table entry information synchronization message; the active PE device sends the ARP table entry information synchronization message to the inactive PE device; and the inactive PE device sends the ARP table entry information synchronization message to the PW master and backup ARP synchronization module for processing. The present invention can effectively improve the performance of protection switching in scenarios where PW master and backup protection and L2VPN access to L3VPN are shared, and has important significance in practical applications.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a method for synchronizing PW primary and backup ARP table entry information. Background Art

[0002] The use of traditional private networks has driven increasing business profits, but they struggle to meet enterprise requirements for network flexibility, security, cost-effectiveness, and scalability. This has prompted the emergence of a new alternative: a solution that emulates traditional private networks on existing IP networks—a virtual private network (VPN). A VPN is a virtual private communication network established within a public network, relying on an Internet Service Provider (ISP) and a Network Service Provider (NSP). Multiple user services can use different L2VPNs, sharing the same public network's tunnel resources, reducing the number of tunnel entries maintained within the public network. VPNs can be categorized into L2VPN and L3VPN based on the protocol layer they implement.

[0003] L2VPN (Layer 2 Virtual Private Network) provides Layer 2 VPN (VPN) services over public networks, transparently transmitting user Layer 2 data over the public network and providing tunneled paths. L2VPN is categorized into VLL (Virtual Leased Line) and VPLS (Virtual Private LAN Service). L2VPN's VPLS simulates the public network as a private Layer 2 switch, offering Layer 2 features such as MAC address learning, restriction, aging, and synchronization. L2VPN is a super private switch, typically used in provincial and municipal metropolitan area networks (MANs) or prefectural access networks. L3VPN is a VPN service established in a Layer 3 network environment, carrying IP packets. L3VPN simulates the public network as a private router, through which customer access devices forward IP (L3) packets. L3VPN can be considered a super private router, often serving as the core of the national backbone network, connecting regional nodes.

[0004] In the metropolitan area network, there is a need for bridging to convert the access L2VPN to the core L3VPN. After adopting L2VPN and L3VPN bridging technology, the L2VPN end node and the L3VPN start node can be merged into one device, which simplifies the network topology and saves equipment costs. Figure 1The PE2 and PE3 nodes shown are both bridge devices that implement the L2VPN access L3VPN function.

[0005] If there is only one PW between two CEs, the CEs will be unable to communicate if a PE node, the link between the PE and CE, or the PW between the PEs fails. Figure 2 As shown in the figure, PW active / standby protection utilizes two PWs (primary and backup) to ensure that if the primary PW fails, traffic is immediately switched to the backup PW, ensuring continued traffic forwarding. Two PW links are established between two CEs. Under normal circumstances, the primary PW is active, and CE1 uses it to communicate with remote CE2. When PE 1 detects that the PW between PE1 and PE2 is unavailable (possibly due to a PE2 node failure, a PW failure between PE1 and PE2, or a link failure between PE2 and CE2), PE 1 activates the backup PW and forwards CE 1's packets to PE 3 via the backup PW, which then forwards them to CE 2. Upon receiving the packets, CE 2 switches packets destined for CE 1 to the backup PW by updating its MAC address table, ensuring uninterrupted communication.

[0006] exist Figure 1 In this scenario, if L2VPN access to L3VPN is enabled on PE2 and PE3, PE2 must obtain CE1's ARP information to ensure it does not discard received traffic from CE1 and that services between CE1 and CE2 can communicate normally. In a typical implementation scenario, PE1 uses PW active / standby protection. CE1's ARP packets are forwarded along the service forwarding channel, and only PE2 receives CE1's ARP information. If a PW active / standby switchover occurs on PE1, traffic from CE1 to CE2 is forwarded from PE1 to PE3 via the backup PW. However, because PE3 lacks CE1's ARP information, it discards the received packets, causing service interruption. Services will not resume until the path between CE1 and CE2 reconverges. Summary of the Invention

[0007] According to an embodiment of the present invention, a method for synchronizing PW primary and backup ARP table entry information is provided, comprising the following steps:

[0008] Build a dual-homed business network;

[0009] Customize the format of ARP table information synchronization messages, including message header information and message payload information;

[0010] The ACL configuration plan is delivered to PE2, PE1, and PE3 in the dual-homing network, establishing a forwarding path for ARP table synchronization messages between the primary and backup PWs in the dual-homing network.

[0011] When receiving a service transmission request in a dual-homed network, if CE1 and CE2 in the dual-homed network transmit services through PE1 and PE2, they periodically send a packetization signal to PE2. At this point, PE2 becomes the active PE and PE3 becomes the inactive PE.

[0012] The active PE device receives the packaging signal regularly, packages its own ARP table entry information, and forms an ARP table entry information synchronization message;

[0013] The active PE device sends the ARP table information synchronization message to the inactive PE device;

[0014] The inactive PE device uses a dedicated ACL rule to match the ARP table information synchronization message and sends the ARP table information synchronization message to the ARP synchronization module of the PW master and backup for processing.

[0015] Furthermore, the message header information is encapsulated using a special reserved address.

[0016] Furthermore, the first part of the payload information of the message is the message fragmentation information, which consists of whether it is fragmented and the fragment ID; the second part is the VSI_INDEX information of the primary and backup PWs; the third part is the number of ARP table entry information in the message; the fourth part is the ARP table entry information actually sent; and the fifth part is the FCS part of the message.

[0017] Furthermore, the active PE device packages its own ARP entry information according to the order in which the ARP entry information is stored.

[0018] Furthermore, the active PE device sends an ARP table entry information synchronization message to the inactive PE device, including the following sub-steps:

[0019] The active PE sends an ARP table information synchronization message to PE1.

[0020] PE1 sends the received ARP entry synchronization message to the inactive PE device.

[0021] Furthermore, the active PE device sends the ARP table information synchronization message to the PE1 device through the ACL or designated port sending technology.

[0022] Furthermore, the PE1 device matches the received ARP table entry information synchronization message through the ALC and sends the ARP table entry information synchronization message to the inactive PE device.

[0023] The method for synchronizing PW primary and backup ARP entry information according to an embodiment of the present invention can effectively improve the performance of protection switching in scenarios where PW primary and backup protection and L2VPN access to L3VPN are shared, and is of great significance in practical applications.

[0024] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the technology as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural block diagram of the PW master-backup and L2VPN access L3VPN sharing scenarios in the existing technology.

[0026] Figure 2 This is a structural diagram of the L2VPN PW primary and backup protection in the prior art.

[0027] Figure 3 A schematic diagram of a format of a customized ARP table entry information synchronization message according to an embodiment of the present invention.

[0028] Figure 4 4 is a structural block diagram of a mechanism for timing transmission of ARP entry information synchronization messages according to an embodiment of the present invention.

[0029] Figure 5 The figure is a flowchart of a method for synchronizing PW primary and backup ARP table entry information according to an embodiment of the present invention.

[0030] Figure 6 The figure is a flowchart of the sub-steps of the method for synchronizing PW primary and backup ARP table entry information according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings to further illustrate the present invention.

[0032] First, combine Figures 3-5 A method for synchronizing PW primary and backup ARP table entry information according to an embodiment of the present invention is described, which is used to implement fast and reliable switching of PW primary and backup in an application scenario where L2VPN accesses L3VPN. The method has a wide range of application scenarios.

[0033] like Figures 3-5 As shown, the method for synchronizing PW primary and backup ARP table entry information according to an embodiment of the present invention includes the following steps:

[0034] In S1, as Figure 5As shown, a dual-homing network is built.

[0035] In S2, as Figure 5 As shown, the format of the customized ARP table entry information synchronization message includes message header information and message payload information. In this embodiment, the message header information can define the message as an IP message format or a simple ETH message format. The message header information is encapsulated using a special reserved address (such as a special MAC address or a special IP address; agreed upon during communication and only used to transmit ARP table entry synchronization information), which can improve the message recognition and reduce the possibility of the message being forwarded unexpectedly. The first part of the message payload information is the message fragmentation information, which consists of whether it is fragmented and the fragment ID; the second part is the VSI_INDEX information of the primary and backup PWs; the third part is the number of ARP table entry information in the message; the fourth part is the ARP table entry information actually sent; and the fifth part is the FCS part of the message.

[0036] In S3, such as Figure 5 As shown, the ACL configuration is delivered to PE2, PE1, and PE3 within the dual-homed service network, establishing a forwarding path for ARP table entry synchronization messages between the primary and backup PWs within the dual-homed service network. In this embodiment, strict matching is performed on customized ARP table entry synchronization messages, effectively ensuring that the channel is dedicated to carrying ARP table entry synchronization messages. Furthermore, the ACL can be used to set the transmission priority on the device, ensuring the transmission quality of the primary and backup PW ARP table entry synchronization messages.

[0037] In S4, as Figure 5 As shown, a service dual-homing network receives a service transmission request. If CE1 and CE2 in the dual-homing network transmit services through PE1 and PE2, they periodically send a packetization signal to PE2. At this point, PE2 is the active PE and PE3 is the inactive PE. In this embodiment, the ARP table synchronization mechanism can adopt a simple mechanism for periodically synchronizing all ARP table entries. The currently active PE periodically packages its own PW primary and backup ARP table entry information and sends it to the currently inactive PE.

[0038] In S5, as Figure 5As shown, the active PE device periodically receives a packetization signal (i.e., after the PW primary and backup ARP table information synchronization timer expires), packages its own ARP table information, and forms an ARP table information synchronization message. In this embodiment, the active PE device packages its own ARP table information in the order in which the ARP table information is stored. Because the active and inactive PE devices use the same PW primary and backup ARP table entry management scheme, the efficiency of ARP table entry recovery on the inactive PE is effectively improved.

[0039] In S6, as Figure 5 As shown, the active PE device sends an ARP table entry information synchronization message to the inactive PE device.

[0040] Further, if Figure 6 As shown in FIG, the active PE device sends an ARP table information synchronization message to the inactive PE device, including the following sub-steps:

[0041] In S61, if Figure 6 As shown in FIG, the active PE device sends the ARP table information synchronization message to the PE1 device through the ACL or the designated port sending technology.

[0042] In S62, if Figure 6 As shown, PE1 sends the received ARP table entry information synchronization message to the inactive PE device. In this embodiment, PE1 matches the received ARP table entry information synchronization message through ALC and sends the ARP table entry information synchronization message to the inactive PE device.

[0043] In S7, such as Figure 5 As shown, the inactive PE device uses a dedicated ACL rule to match ARP table entry synchronization messages and sends these messages to the ARP synchronization modules of the primary and backup PWs for processing. In the scheduled ARP table entry synchronization mechanism, upon receiving these scheduled messages, the inactive PE device can directly overwrite the local ARP table entries of the primary and backup PWs. In this embodiment, the dedicated ACL rule is specifically created to match ARP table entry synchronization messages.

[0044] Alternatively, a solution can be adopted that only transmits ARP table entries that have been added or removed from the currently active PE device. In this case, the format of the ARP table entry synchronization message must be redefined. Consider transmitting new and removed ARP table entries in separate messages, distinguishing the two types of messages using the message header format. Separately processing new and removed ARP table entries can effectively improve ARP table entry synchronization efficiency. To reduce the number of ARP table entry synchronization messages sent, a solution can also be adopted that periodically transmits changed ARP table entry information.

[0045] Above, refer to Figures 3 to 6 The present invention describes a method for synchronizing PW primary and backup ARP table information, which can effectively improve the performance of protection switching in scenarios where PW primary and backup protection and L2VPN access L3VPN are shared, and has important practical significance.

[0046] It should be noted that, in this specification, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, the elements defined by the phrase "comprising..." do not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the elements.

[0047] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for synchronizing PW primary and backup ARP table information, characterized in that: The following steps are included: Build a dual-homed business network; Customize the format of ARP table information synchronization messages, including message header information and message payload information; The ACL configuration scheme is issued to the PE2, PE1, and PE3 devices in the dual-homing network, and a forwarding path for the ARP table information synchronization message of the primary and backup PWs in the dual-homing network is established; The service dual-homing network receives a service transmission request. If the CE1 device and the CE2 device in the service dual-homing network transmit services through the PE1 device and the PE2 device, a packet signal is periodically sent to the PE2 device. At this time, the PE2 device is the active PE device and the PE3 device is the inactive PE device. The active PE device receives the packaging signal at regular intervals, packages the ARP table entry information of the active PE device itself, and forms an ARP table entry information synchronization message; The active PE device sends the ARP table entry information synchronization message to the inactive PE device; The inactive PE device matches the ARP table entry information synchronization message using a special ACL rule, and sends the ARP table entry information synchronization message to the ARP synchronization module of the PW master and backup for processing.

2. The method for synchronizing PW primary and backup ARP table information according to claim 1, wherein: The message header information is encapsulated using a special reserved address.

3. The method for synchronizing PW primary and backup ARP table information according to claim 1 or 2, characterized in that: The first part of the payload information of the message is the message fragmentation information, which consists of whether it is fragmented and the fragment ID; the second part is the VSI_INDEX information of the primary and backup PWs; the third part is the number of ARP table entry information in the message; the fourth part is the ARP table entry information actually sent; and the fifth part is the FCS part of the message.

4. The method for synchronizing PW primary and backup ARP table information according to claim 1, wherein: The active PE device packages its own ARP table entry information according to the order in which the ARP table entry information is stored.

5. The method for synchronizing PW primary and backup ARP table information according to claim 1, wherein: The active PE device sending the ARP table entry information synchronization message to the inactive PE device includes the following sub-steps: The active PE device sends the ARP table entry information synchronization message to the PE1 device; The PE1 device sends the received ARP table entry information synchronization message to the inactive PE device.

6. The method for synchronizing PW primary and backup ARP table information according to claim 5, wherein: The active PE device sends the ARP table entry information synchronization message to the PE1 device through ACL or designated port sending technology.

7. The method for synchronizing PW primary and backup ARP table information according to claim 5 or 6, characterized in that: The PE1 device matches the received ARP table entry information synchronization message through ALC, and sends the ARP table entry information synchronization message to the inactive PE device.

Images