Method and equipment for realizing horizontal segmentation forwarding
By using ESI identifiers in EVPN multi-home networks, horizontal segmentation and forwarding of BUM messages is achieved, which solves the problem of insufficient hardware resources of PE equipment and improves network capacity expansion capabilities and forwarding efficiency.
Patent Information
- Application Number
- CN202510730084.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-07-25
AI Technical Summary
In EVPN multi-home network, due to the increase in CE devices and insufficient hardware resources of PE devices, it is impossible to assign sufficient ESI identifiers to each CE device, resulting in repeated reception of loops and BUM messages, limiting network expansion.
By sharing ESI identifiers, horizontal segmentation forwarding of BUM messages is realized, simplifying the forwarding process of PE devices, and avoiding loops and repeated reception.
The forwarding process of BUM packets in EVPN multi-home network is simplified, the network's capacity expansion capability is improved, and loop problems caused by insufficient hardware resources are avoided.
Smart Images
Figure CN120378251A_ABST
Abstract
Description
Technical Field
[0001] This application relates to communication technologies, and more specifically, to a method and device for implementing split-horizon forwarding. Background Art
[0002] EVPN (Ethernet Virtual Private Network) is a Layer 2 VPN (Virtual Private Network) technology. The control plane uses MP-BGP (Multiprotocol Border Gateway Protocol) to advertise EVPN routing information, and the data plane uses VXLAN or MPLS encapsulation to forward packets. When the physical sites of tenants are scattered in different locations, EVPN can provide Layer 2 interconnection for the same subnet of the same tenant based on the existing service provider or enterprise IP network.
[0003] EVPN multi-homing means that a site accesses multiple PEs (Provider Edge) in the EVPN network through different Ethernet links, and the multiple accessed PEs form a redundant backup group, and the traffic of this site is load-shared among the multiple PEs. The use of multi-homing technology can avoid the interruption of EVPN network communication caused by a single point of failure of the PE, thus improving the reliability of the EVPN network.
[0004] In an EVPN multi-homing network, a group of links of a redundant backup group of multiple PEs (Provider Edge) to which a CE device of a site is multi-homed accesses form an ES (Ethernet Segment), and an ESI (Ethernet Segment Identifier) is configured. In this way, when a PE device receives broadcast, unknown unicast, and multicast BUM (Broadcast, Unknown Unicast, Multicast) packets from different site CEs (Customer Edge), it needs to encapsulate the corresponding ESI and send them to other PE devices in the same redundant backup group. In this way, the PE device sends the BUM to the CE device assigned with other ESIs for split-horizon forwarding, avoiding the formation of a forwarding loop or the repeated reception of BUM packets. However, with the increase in the number of CE devices due to the increase in network scale, all CE devices accessing the same redundant backup group need to be assigned a unique ESI identifier. If the hardware resources of the PE device are insufficient when the PE device receives BUM, it is unable to allocate enough ESIs or does not have enough hardware forwarding resources to support the addition of ESI identifiers, which will lead to a loop and limit the expansion of sites within the network device. Summary of the Invention
[0005] The purpose of this application is to provide a method and device for implementing split-horizon forwarding, which simplifies the broadcast, unknown unicast, and multicast BUM forwarding between PEs in the redundant backup group of EVPN multi-homing.
[0006] To achieve the above object, this application provides a method for implementing split-horizon forwarding. The method includes: receiving the peer common Ethernet segment identifier ESI announced by the peer device of the redundant backup group; announcing the local common ESI to the peer device; receiving a first BUM packet carrying the peer common ESI sent by the peer device; stripping the peer common ESI of the first BUM packet; finding the multi-homing access ports in the working state on the peer device of the multi-homing access device; determining not to send the first BUM packet through the local multi-homing access port connecting the multi-homing access device; sending a copy of the first BUM packet through the local single-homing access port of the single-homing access device.
[0007] To achieve the above object, this application also provides a device for implementing split-horizon forwarding. The device includes an announcement unit for receiving the peer common Ethernet segment identifier ESI announced by the peer device of the redundant backup group; announcing the local common ESI to the peer device; a receiving unit for receiving the first BUM packet carrying the peer common ESI sent by the peer device; a forwarding unit for stripping the peer common ESI of the first BUM packet; finding the multi-homing access ports in the working state on the peer device of the multi-homing access device; determining not to send the first BUM packet through the local multi-homing access port connecting the multi-homing access device; a sending unit for sending a copy of the first BUM packet through the local single-homing access port of the single-homing access device.
[0008] The beneficial effect of this application is that each PE device in the redundant backup group of the EVPN multi-homing network does not need to allocate an ESI for each CE device. The common ESI is used to identify and forward the BUM packets that need to be split-horizon forwarded from the PE devices in the redundant backup group, which simplifies the split-horizon forwarding of the BUM packets in the redundant backup group of the EVPN multi-homing network. Description of the Drawings
[0009] Figure 1 It is a flowchart of an embodiment of a method for implementing split-horizon forwarding provided by this application;
[0010] Figure 2 It is a schematic diagram of an Ethernet virtual private network multi-homing network provided by this application;
[0011] Figures 3A-3B It is a schematic diagram of broadcast unknown unicast multicast packet forwarding provided by this application;
[0012] Figure 4Schematic diagram of an apparatus embodiment for implementing horizontal split forwarding provided by this application. Detailed implementation manners
[0013] Multiple examples shown in multiple drawings will be described in detail. In the following detailed description, multiple specific details are used to provide a comprehensive understanding of this application. Known methods, steps, components, and circuits are not described in detail in the examples to avoid making these examples difficult to understand.
[0014] Among the terms used, the term "including" means including but not limited to; the term "containing" means including but not limited to; the terms "above", "within", and "below" include the number itself; the terms "greater than" and "less than" do not include the number itself. The term "based on" means at least based on a part of it.
[0015] Figure 1 An embodiment of a method for implementing horizontal split forwarding provided by this application includes the following steps:
[0016] Step 101, receiving the peer common Ethernet segment identifier (ESI) announced by the peer device of the redundant backup group;
[0017] Step 102, announcing the local common ESI to the peer device;
[0018] Step 103, receiving a BUM packet carrying the peer common ESI sent by the peer device;
[0019] Step 104, stripping the peer common ESI of the BUM packet;
[0020] Step 105, finding the multi-homed access ports in the working state on the peer device of the multi-homed access device, and determining not to send the BUM packet through the local multi-homed access port connecting the multi-homed access device;
[0021] Step 106, sending a BUM packet through the local single-homed access port of the single-homed access device.
[0022] Figure 1 The beneficial effect of the embodiment is that each PE device in the redundant backup group of the EVPN multi-homed network does not need to allocate an ESI for each CE device, and the BUM packets that need to be horizontally split and forwarded from the PE devices in the redundant backup group are identified and forwarded through the common ESI; the horizontal split and forwarding of the BUM packets in the redundant backup group of the EVPN multi-homed network is simplified.
[0023] Figure 2 Schematic diagram of an Ethernet virtual private network multi-homed network provided by this application.
[0024] PE21 and PE22 belong to the same redundancy backup group and are connected to the peer PE23 through a tunnel (Tunnle). The CE24 at the first site ( Figure 2 not shown) is single-homed to access PE21, and the CE27 at the fourth site ( Figure 2 not shown) is single-homed to access PE22. The CE25 at the second site ( Figure 2 not shown) and the CE26 at the third site ( Figure 2 not shown) are multi-homed to access PE21 and PE22 respectively.
[0025] On PE21, configure and record that CE24 is single-homed to access port 4; configure and record that CE25 is multi-homed to access port 5a and the peer PE port 5b; configure and record that CE26 is multi-homed to access port 6a and the peer PE port 6b.
[0026] On PE22, configure and record that CE25 is multi-homed to access port 5b and the peer PE port 5a; configure and record that CE26 is multi-homed to access port 6b and the peer PE port 6a; configure and record that CE27 is single-homed to access port 4.
[0027] PE21 assigns a common ESI 210 to the locally accessed CE24, CE25, and CE26, which is used to indicate that CE 24, 25, and 26 access the same PE21 in the redundancy backup group; the common ESI210 is advertised to PE22 through the EVPN protocol message P1.
[0028] PE22 assigns a common ESI 220 to the locally accessed CE25, CE26, and CE27, which is used to indicate that CE25, 26, and 27 access the same PE22 in the redundancy backup group; the common ESI220 is advertised to PE21 through the EVPN protocol message P2.
[0029] PE21 detects that the single-homed access port 4, the multi-homed access port 5a, and the multi-homed access port 6a are in the working state (UP). PE21 advertises the working state (UP) of the local multi-homed access ports 5a and 6a of the multi-homed access devices CE25 and CE26 to the peer PE22 through the EVPN protocol message P3.
[0030] PE22 receives the EVPN protocol message P3 and records that the multi-homed access ports 5a and 6A of the multi-homed access devices CE25 and CE26 at the peer PE21 are in the working state.
[0031] The PE22 detection form belongs to access port 7. The multi-homed access ports 5b and 6b are in the working state. PE22 notifies the working states of the local multi-homed access ports 5b and 6b of the multi-homed access devices CE25 and CE26 to the peer PE21 through the EVPN protocol packet P4.
[0032] PE21 receives the EVPN protocol packet P4 and records that the multi-homed access ports 5b and 6b of the multi-homed access devices CE25 and CE26 at the peer PE22 are in the working state.
[0033] Figures 3A-3B This is the forwarding schematic diagram of the broadcast unknown unicast multicast packet provided by this application.
[0034] Figure 3A In it, CE24 sends the BUM packet 31; PE21 receives the BUM packet 31 through the single-homed access port 4, forwards it locally, and sends a copy of the BUM packet 31 to CE25 and CE26 respectively through the local multi-homed access ports 5a and 6a.
[0035] PE21 copies a BUM packet 31, encapsulates it based on the tunnel connecting to PE22, and sends the encapsulated BUM packet to PE23. After receiving the tunnel-encapsulated BUM packet 31, PE23 de-encapsulates it and sends the BUM packet 31 to CE28.
[0036] PE21 copies a BUM packet 31, adds the local common ESI210, and sends the BUM packet 31 carrying the local common ESI210 to PE22.
[0037] PE22 receives the BUM packet 31 with the common ESI210 and strips off the common ESI210.
[0038] If PE22 finds that the multi-homed access port 5a of the multi-homed access device CE25 connected to the local multi-homed access port 5b is in the working state at the peer PE21, it will not send the BUM packet 31 through the local multi-homed access port 5b.
[0039] If PE22 finds that the multi-homed access port 6a of the multi-homed access device CE25 connected to the local multi-homed access port 6b is in the working state at the peer PE21, it will not send the BUM packet 31 through the local multi-homed access port 6b.
[0040] PE22 sends a BUM packet 31 to CE27 through the local single-homed access port 7.
[0041] Figure 3BAmong them, the link between CE25 and PE22 fails; PE22 detects that the multi-homed access port 5b is in the down state, and notifies the down state of the local multi-homed access port 5b of the multi-homed access device CE25 to the peer PE22 through the EVPN protocol message P5.
[0042] PE21 receives the EVPN protocol message P5 and updates that the multi-homed access port 5b of the multi-homed access device CE25 at the peer PE22 is in the down state.
[0043] Figure 3B Among them, CE26 sends the BUM message 32; PE22 receives the BUM message 32 through the multi-homed access port 6b, forwards it locally, and sends a copy of the BUM message to CE27 through the single-homed access port 7.
[0044] PE22 duplicates a copy of the BUM message 32, encapsulates it based on the tunnel connecting to PE23, and sends the encapsulated BUM message to PE23. After receiving the tunnel-encapsulated BUM message 32, PE23 decapsulates it and sends the BUM message 32 to CE28.
[0045] PE22 duplicates a copy of the BUM message 32, adds the local common ESI220, and sends the BUM message 32 carrying the common ESI220 to PE22.
[0046] PE21 receives the BUM message 32 with the common ESI220 and strips off the common ESI220. If PE21 finds that the multi-homed access port 5b of the multi-homed access device 25 at the peer PE22 is in the down state, it sends a copy of the BUM message 32 through the local multi-homed access port 5a.
[0047] If PE21 finds that the multi-homed access port 6b of the multi-homed access device CE26 at the peer PE22 is in the working state, it determines to send the BUM message 32 through the local multi-homed access port 6a of the different multi-homed access device CE26.
[0048] PE21 sends a copy of the BUM message 32 to the local single-homed access device CE24 through the local single-homed access port 4.
[0049] The beneficial effect of the embodiment of the present application is that each PE device in the redundant backup group of the EVPN multi-homed network does not need to allocate an ESI for each CE device, and the common ESI is used to identify and forward the BUM messages that need to be split and forwarded horizontally by the PE devices from the redundant backup group; the horizontal split and forwarding of the BUM messages in the redundant backup group of the EVPN multi-homed network is simplified.
[0050] Figure 4Schematic diagram of an apparatus embodiment for implementing horizontal split forwarding provided by this application. The apparatus 400 includes an advertisement unit 410, a receiving unit 420, a forwarding unit 430, and a sending unit 440.
[0051] The advertisement unit 410 is configured to receive the end - to - end common Ethernet segment identifier ESI advertised by the peer device of the redundant backup group; advertise the local common ESI to the peer device; the receiving unit 420 receives the first BUM packet carrying the end - to - end common ESI sent by the peer device; the forwarding unit 430 strips the end - to - end common ESI of the first BUM packet; finds the multi - homed access port in the working state on the peer device of the multi - homed access device; determines not to send the first BUM packet through the local multi - homed access port connecting the multi - homed access device; the sending unit 440 sends a copy of the first BUM packet through the local single - homed access port of the single - homed access device.
[0052] The advertisement unit 410 is further configured to receive the multi - homed access port in the working state of the multi - homed access device on the peer device advertised by the peer device; advertise the local multi - homed access port in the working state of the multi - homed access device to the peer device.
[0053] The advertisement unit 410 is further configured to receive that the multi - homed access port of the multi - homed access device on the peer device is in the closed state;
[0054] The receiving unit 420 is further configured to receive the second BUM packet carrying the end - to - end common ESI sent by the peer device; the forwarding unit 430 is further configured to strip the end - to - end common ESI of the second BUM packet, find the multi - homed access port in the closed state on the peer device of the multi - homed access device, and determine to send a copy of the second BUM packet through the local multi - homed access port connecting the multi - homed access device; the sending unit 440 sends a copy of the second BUM packet through the local multi - homed access port connecting the multi - homed access device and the local single - homed access port of the single - homed access device respectively.
[0055] The receiving unit 420 is further configured to receive a third BUM packet through the local single - homed access port of the single - homed access device; the forwarding unit 430 is configured to determine to send a copy of the third BUM packet through the local multi - homed access port of the multi - homed access device and the peer device respectively; the sending unit 440 is configured to send a copy of the third BUM packet through the local multi - homed access port of the multi - homed access device, and send a third BUM packet with the local common ESI through the link interface connecting the peer device.
[0056] The advertisement unit 410 is further configured to obtain that the local multi - homed access port of the multi - homed access device is in the closed state; the local multi - homed access port of the multi - homed access device advertised by the peer device is in the closed state.
[0057] In this application, the machine-readable storage medium can be any electronic, magnetic, optical, or other physical storage device used to store or contain information (such as executable instructions, data, etc.). For example, any machine-readable storage medium described herein can be any type of random access memory (RAM), volatile memory, non-volatile memory, flash memory, storage drive (such as a hard disk drive), solid-state drive, any type of storage optical disc (such as a CD, DVD, etc.), and similar devices, or a combination thereof. In addition, any machine-readable storage medium herein can be a non-transitory machine-readable storage medium.
[0058] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the scope of protection of this application.
Claims
1. A method for implementing horizontal splitting and forwarding, characterized in that, The method includes, receiving the peer common Ethernet segment identifier ESI announced by the peer device of the redundant backup group; announcing the local common ESI to the peer device; receiving a first BUM packet carrying the peer common ESI sent by the peer device; stripping the peer common ESI of the first BUM packet; finding a multi-homed access port of the multi-homed access device that is in a working state on the peer device, and determining not to send the first BUM packet through the local multi-homed access port connecting the multi-homed access device; sending a copy of the first BUM packet through the local single-homed access port of the single-homed access device.
2. The method according to claim 1, characterized in that, Before receiving the first BUM packet carrying the common ESI sent by the peer device, the method further includes, receiving the multi-homed access port of the multi-homed access device that is in a working state on the peer device announced by the peer device; announcing the local multi-homed access port of the multi-homed access device that is in a working state to the peer device.
3. The method according to claim 2, wherein The method further includes, receiving that the multi-homed access port of the multi-homed access device on the peer device is in a closed state announced by the peer device; receiving a second BUM packet carrying the peer common ESI sent by the peer device; stripping the peer common ESI of the second BUM packet; finding a multi-homed access port of the multi-homed access device that is in a closed state on the peer device; determining to send a copy of the second BUM packet through the local multi-homed access port connecting the multi-homed access device; sending a copy of the second BUM packet through the local single-homed access port of the single-homed access device.
4. The method according to claim 1, characterized in that, The method further includes, receiving a third BUM packet through the local single-homed access port of the single-homed access device; sending a copy of the third BUM packet through the local multi-homed access port of the multi-homed access device; sending a copy of the third BUM packet with the local common ESI to the peer device.
5. The method according to claim 4, wherein The method further includes obtaining the closed state of the local multi-homed access port of the multi-homed access device; the local multi-homed access port of the multi-homed access device announced by the peer device is in a closed state.
6. A device for implementing horizontal split forwarding, characterized in that, The device includes, an announcement unit, configured to receive the peer common Ethernet segment identifier ESI announced by the peer device of the redundant backup group; announce the local common ESI to the peer device; a receiving unit, configured to receive a first BUM packet carrying the peer common ESI sent by the peer device; a forwarding unit, configured to strip the peer common ESI of the first BUM packet; find a multi-homed access port of the multi-homed access device that is in a working state on the peer device; determine not to send the first BUM packet through the local multi-homed access port connecting the multi-homed access device; a sending unit, configured to send a copy of the first BUM packet through the local single-homed access port of the single-homed access device.
7. The device according to claim 6, wherein The notification unit is further configured to receive the multi-homed access ports of the multi-homed access device notified by the peer device in the working state of the peer device; and notify the local multi-homed access ports of the working state of the multi-homed access device notified by the peer device to the peer device.
8. The device according to claim 7, wherein the notification unit is further configured to receive that the multi-homed access ports of the multi-homed access device notified by the peer device are in a closed state at the peer device; the receiving unit is further configured to receive a second BUM packet carrying the peer common ESI sent by the peer device; the forwarding unit is further configured to strip the peer common ESI from the second BUM packet, find the multi-homed access ports of the multi-homed access device in a closed state at the peer device, and if determined, send one copy of the second BUM packet through the local multi-homed access port connecting the multi-homed access device; the sending unit sends one copy of the second BUM packet through the local multi-homed access port connecting the multi-homed access device and the local single-homed access port of the single-homed access device respectively.
9. The device according to claim 6, wherein the receiving unit is further configured to receive one copy of the third BUM packet through the local single-homed access port of the single-homed access device; the forwarding unit is configured to determine to send one copy of the third BUM packet through the local multi-homed access port of the multi-homed access device and the peer device respectively; the sending unit is configured to send one copy of the third BUM packet through the local multi-homed access port of the multi-homed access device, and send one copy of the third BUM packet with the local common ESI through the link interface connecting the peer device.
10. The device according to claim 9, wherein the notification unit is further configured to obtain that the local multi-homed access port of the multi-homed access device is in a closed state; and the local multi-homed access port of the multi-homed access device notified by the peer device is in a closed state.