A method and device for multi-chassis access protection of an EVPN service

Abstract

The embodiment of the application aims to provide a method and device for multi-frame access protection of EVPN service. The method comprises: configuring a multi-frame redundant access mode of EVPN service; wherein the multi-frame redundant access mode is applicable to a scenario that two or more access node (AN) devices of an access protection group are connected to a cloud center office (Cloud CO), and the two or more AN devices are respectively dual-connected to the same pair of PE devices. The embodiment of the application has the following advantages: a new redundant protection mode of EVPN multi-connection is provided, which is applicable to the scenario of Cloud CO multi-frame redundant access; redundant mode coding, ESI coding and EVPN route coding involved in the new redundant protection mode of EVPN multi-connection, and various EVPN multi-connection functions are provided, so that the scenario of Cloud CO multi-frame redundant access is better adapted.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and in particular to a multi-chassis access protection method and device for an EVPN service. Background Art

[0002] In a Cloud Central Office (CloudCO) scenario, access nodes (AN) are stacked within point of delivery (POD) modules. The provider edge routers (PE) in the PODs run Ethernet virtual private network (EVPN) services to interconnect various network elements across the CloudCO network.

[0003] Unlike traditional EVPN multi-homing scenarios where access links are directly connected to PE devices, in CloudCO scenarios, access links are indirectly connected to PE devices through AN devices. That is, the access links are directly connected to AN devices, and AN devices are directly connected to PE devices.

[0004] The existing EVPN multi-homing redundancy mode is not suitable for CloudCO multi-chassis redundant access scenarios. Summary of the Invention

[0005] The purpose of the embodiments of the present application is to provide a multi-chassis access protection method and device for EVPN services.

[0006] An embodiment of the present application provides a multi-chassis access protection method for an EVPN service, wherein the method includes:

[0007] Configure a multi-chassis redundant access mode for EVPN services.

[0008] Among them, the multi-chassis redundant access mode is applicable to the scenario where an access protection group is multi-homed connected to two or more access node (AN) devices of a cloud central office (CloudCO), and these two or more AN devices are dual-homed connected to the same pair of PE devices.

[0009] An embodiment of the present application provides a multi-chassis access protection device for an EVPN service, wherein the device includes:

[0010] A device for configuring a multi-chassis redundant access mode for an EVPN service;

[0011] The multi-chassis redundant access mode is applicable to a scenario where an access protection group is multi-homed to two or more AN devices connected to CloudCO, and the two or more AN devices are dual-homed to the same pair of PE devices.

[0012] An embodiment of the present application provides a PE device for multi-chassis access protection of an EVPN service, wherein the PE device includes a processor and a memory, wherein the memory stores a computer program. When the computer program is executed by the processor, the following steps are implemented:

[0013] Configure a multi-chassis redundant access mode for EVPN services.

[0014] The multi-chassis redundant access mode is applicable to a scenario where an access protection group is multi-homed to two or more AN devices connected to CloudCO, and the two or more AN devices are dual-homed to the same pair of PE devices.

[0015] An embodiment of the present application provides a computer-readable storage medium having a computer program stored therein, the computer program being used in a PE device for multi-chassis access protection of an EVPN service;

[0016] When the computer program is executed by a PE device, the following steps are performed:

[0017] Configure a multi-chassis redundant access mode for EVPN services.

[0018] The multi-chassis redundant access mode is applicable to a scenario where an access protection group is multi-homed to two or more AN devices connected to CloudCO, and the two or more AN devices are dual-homed to the same pair of PE devices.

[0019] Compared with the prior art, the embodiments of the present application have the following advantages: providing a new redundant protection mode for EVPN multi-homing connections, which is suitable for scenarios where CloudCO multi-chassis redundant access is required; providing redundant mode coding, ESI coding, and EVPN route coding involved in supporting the redundant protection mode for EVPN multi-homing connections, and describing various EVPN multi-homing connection functions, thereby better adapting to scenarios where CloudCO multi-chassis redundant access is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0021] Figure 1 A flowchart of a multi-chassis access protection method for an EVPN service according to an embodiment of the present application is shown;

[0022] Figure 2 A schematic diagram showing the structure of a network system of an exemplary CloudCO scenario according to an embodiment of the present application is shown;

[0023] Figure 3 A structural diagram of a multi-chassis access protection device for EVPN services according to an embodiment of the present application is shown.

[0024] The same or similar reference numerals in the drawings represent the same or similar components. DETAILED DESCRIPTION

[0025] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the various operations as sequential processes, many of the operations therein can be implemented in parallel, concurrently, or simultaneously. In addition, the order of the various operations can be rearranged. The process can be terminated when its operation is completed, but can also have additional steps not included in the accompanying drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0026] The methods discussed below (some of which are illustrated by flow charts) can be implemented by hardware, software, firmware, middleware, microcode, hardware description language, or any combination thereof. When implemented by software, firmware, middleware, or microcode, the program code or code segments for performing the necessary tasks can be stored in a machine or computer readable medium (such as a storage medium). (One or more) processors can perform the necessary tasks.

[0027] The specific structural and functional details disclosed herein are merely representative and are for the purpose of describing exemplary embodiments of the present invention. However, the present invention may be embodied in many alternative forms and should not be construed as being limited to only the embodiments set forth herein.

[0028] It should be understood that although the terms "first," "second," and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used solely to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the exemplary embodiments. The term "and / or" as used herein includes any and all combinations of one or more of the listed associated items.

[0029] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent to" versus "directly adjacent to," etc.).

[0030] The terms used herein are intended only to describe specific embodiments and are not intended to limit exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "a", "an", "an item" used herein are also intended to include the plural. It should also be understood that the terms "comprise" and / or "include" used herein specify the presence of stated features, integers, steps, operations, units and / or components, and do not preclude the presence or addition of one or more other features, integers, steps, operations, units, components and / or combinations thereof.

[0031] It should also be noted that, in some alternative implementations, the functions / actions mentioned may occur in a different order than that indicated in the accompanying drawings. For example, two figures shown in succession may actually be performed substantially simultaneously or may sometimes be performed in the reverse order, depending on the functions / actions involved.

[0032] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the exemplary embodiments belong. It should also be understood that, unless expressly defined herein, terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense.

[0033] The present invention is further described in detail below with reference to the accompanying drawings.

[0034] Figure 1 A flowchart of a multi-chassis access protection method for an EVPN service according to an embodiment of the present application is shown. The method includes step S1.

[0035] Reference Figure 1 In step S1, a multi-chassis redundant access mode of an EVPN service is configured.

[0036] Among them, the multi-chassis redundant access mode is applicable to the scenario where an access protection group is multi-homed connected to two or more access node (AN) devices of a cloud central office (CloudCO), and these two or more AN devices are dual-homed connected to the same pair of PE devices.

[0037] The access protection group generally refers to client devices or networks using various multi-homing access technologies, such as a link aggregation group, an Ethernet linear protection group, or an ITU-T Type B / Type C or IEEE trunk / tree passive optical network protection group.

[0038] If an access protection group is dual-homed to two CloudCO AN devices, the access protection group corresponds to a virtual Ethernet segment on the PE device, which contains four Ethernet virtual circuits carried on the four physical Ethernet links connecting the PE and AN. This virtual Ethernet segment is further divided into two sub-Ethernet segments, each containing two different Ethernet virtual circuits, each corresponding to a physical access link of the access protection group.

[0039] Among them, in the multi-frame redundant access mode, the virtual Ethernet segment corresponding to an access protection group can be divided into two or more sub-Ethernet segments; the virtual Ethernet segment can operate in the sub-Ethernet segment full-active mode or the sub-Ethernet segment single-active mode; each sub-Ethernet segment can be set as the main sub-Ethernet segment or the backup sub-Ethernet segment.

[0040] If the virtual Ethernet segment works in the sub-Ethernet segment all-active mode, then each of its corresponding sub-Ethernet segments is the active sub-Ethernet segment; if the virtual Ethernet segment works in the sub-Ethernet segment single-active mode, then one of the sub-Ethernet segments is the active sub-Ethernet segment, and the other sub-Ethernet segments are backup sub-Ethernet segments.

[0041] The following describes an exemplary CloudCO scenario network system embodiment of the present application.

[0042] Figure 2 A schematic structural diagram of a network system in an exemplary CloudCO scenario according to an embodiment of the present application is shown.

[0043] Reference Figure 2 The network elements in this network system include a multi-chassis access protection group (MC-APG), a pair of AN devices (AN1 and AN2), a pair of PE devices (PE1 and PE2) forming a PE redundancy group, a remote PE device (PE3), and a network / service gateway. PE1, PE2, and PE3 each maintain their own virtual MAC address routing and forwarding table (MAC-VRF).

[0044] The MC-APG is dual-homed to AN1 and AN2 via two access links (Access Link 1 and Access Link 2). AN1 and AN2, as well as PE1 and PE2, are connected via four physical links: PE-AN Link 1 from AN1 to PE1, PE-AN Link 2 from AN2 to PE1, PE-AN Link 3 from AN1 to PE2, and PE-AN Link 4 from AN2 to PE2. PE-AN Link 1 through PE-AN Link 4 correspond to MAC addresses MAC1 to MAC4, respectively.

[0045] The four links are bundled into two independent active-active multi-chassis link aggregation groups (MC-LAGs), and each MC-LAG is identified by its own AN IPv4 address.

[0046] The MC-APG corresponds to a virtual Ethernet segment (vES), which includes four Ethernet virtual circuits (EVCs) EVC1 to EVC4, respectively, carried on the four physical links. The vES is divided into two sub-segments, Sub-ES1 and Sub-ES2. Sub-ES1 includes Ethernet virtual circuits EVC1 and EVC2, while Sub-ES2 includes Ethernet virtual circuits EVC3 and EVC4.

[0047] If the EVC on the virtual Ethernet segment is implemented as a service virtual local area network (S-VLAN), EVC1 through EVC4 should all use the same S-VLAN identifier. In this case, one MC-APG corresponds to one S-VLAN identifier. If the access link terminates on an S-VLAN bridge between AN1 and AN2, they should learn MAC addresses independently based on the S-VLAN. The access link can also terminate on an S-VLAN cross-connect (XC) between AN1 and AN2.

[0048] The following describes the encoding method of the Ethernet Segment Identifier (ESI) used in the solution of the embodiment of the present application.

[0049] The method according to the embodiment of the present application adopts an encoding method of virtual Ethernet segment identifier (vESI), sub-Ethernet segment identifier (Sub-ESI) and Ethernet virtual circuit identifier (EVC ID) that is compatible with the standard EVPN routing encoding format.

[0050] According to one embodiment, both the virtual Ethernet segment and the sub-Ethernet segment are globally uniquely identified by a 10-byte ESI, which is encoded as follows:

[0051] The highest byte of the 10-byte ESI of both the virtual Ethernet segment and the sub-Ethernet segment contains a new ESI type code, denoted as T_SUB_ESED;

[0052] The most significant 6 bytes of the 10-byte ESI (which contains the ESI type code byte) are called the Virtual Ethernet Segment Identifier field. Its value globally uniquely identifies a virtual Ethernet segment. The 10-byte ESI value of this field should be the same for a virtual Ethernet segment and all its child Ethernet segments.

[0053] The lowest 4 bytes of the 10-byte ESI are called the Sub-Ethernet Segment field. This field value identifies a sub-Ethernet segment relative to the 6-byte Virtual Ethernet Segment Identifier value. The Sub-Ethernet Segment field values ​​0 and 0xFFFFFFFF are reserved.

[0054] The 10-byte ESI with the ESI type code of T_SUB_ESED and the sub-Ethernet segment field value of 0xFFFFFFFF globally uniquely identifies a virtual Ethernet segment operating in the multi-chassis redundant access mode. This form of ESI is called vESI.

[0055] A 10-byte ESI with an ESI type code of T_SUB_ESED and a non-reserved value in the Sub-Ethernet Segment field uniquely identifies a sub-Ethernet segment operating in multi-chassis redundant access mode. This form of ESI is called a Sub-ESI. Its associated vESI can be obtained by setting the value of the Sub-Ethernet Segment field to 0xFFFFFFFF.

[0056] In the CloudCO scenario, the 6-byte virtual Ethernet segment identifier also globally uniquely identifies the MC-APG. In the 10-byte Sub-ESI, the 4-byte sub-Ethernet segment identifier field is encoded as an AN IPv4 address. Each EVC of the virtual Ethernet segment can be composed of 14 bytes.<Sub-ESI,PE IPv4地址> In the context of a virtual Ethernet segment, the EVC ID can be simplified to 8 bytes.<AN IPv4地址,PE IPv4地址> Concatenation; in the context of a sub-Ethernet segment, the EVC ID is further simplified to a 4-byte PE IPv4 address.

[0057] To support the multi-chassis redundant access mode, the method defines three new bits "Sub-ESed", "Sub-mode-flagl" and "Sub-mode-flag2" in the Flags field of the ESI Label Extended Community to indicate the multi-chassis redundant access mode and its sub-modes. A "Sub-ESed" value of 1 indicates that the virtual Ethernet segment operates in the multi-chassis redundant access mode. "Sub-mode-flagl" and "Sub-mode-flag2" indicate the sub-modes of the multi-chassis redundant access mode only when the "Sub-ESed" value is 1. When the "Sub-ESed" value is 0, "Sub-mode-flagl" and "Sub-mode-flag2" bits are undefined.

[0058] Table 1 exemplarily defines "Sub-ESed", "Sub-mode-flagl" and "Sub-mode-flag2" as the three highest order bits of the Flags field, and lists the multi-chassis redundant access mode and its sub-modes indicated by the Flags field values:

[0059] Table 1

[0060] Flags field value Redundancy Mode Submode Applicable to vESI or Sub-ESI 0b10000000 Sub-ESed Sub-Ethernet segment full live Virtual Ethernet segment 0b11100000 Sub-ESed Single active sub-Ethernet segment Virtual Ethernet segment 0b11000000 Sub-ESed Active sub-Ethernet segment Sub-Ethernet segment 0b10100000 Sub-ESed Spare sub-Ethernet segment Sub-Ethernet segment

[0061] wherein "Sub-ESed" represents the multi-chassis redundant access mode of the embodiments of the present application.

[0062] The EVPN route encoding configured in the scheme of the embodiments of the present application is described below.

[0063] In the multi-chassis redundant access mode, each PE device advertises the following EVPN routes for the virtual Ethernet segment corresponding to an access protection group:

[0064] 1) an Ethernet auto-discovery route corresponding to the virtual Ethernet segment;

[0065] According to an embodiment, each PE device advertises an Ethernet auto-discovery route corresponding to the virtual Ethernet segment, as well as an ESI Label Extended Community and a Route Target Extended Community.

[0066] The Ethernet auto-discovery route corresponding to the virtual Ethernet segment and the Route Target Extended Community are encoded in the manner specified in RFC7432 §8.2.1. The Ethernet Segment Identifier field contains a 10-byte vESI.

[0067] The ESI tag's extended community attribute is encoded according to RFC 7432 §7.5. The Flags field is set to 0b10000000 or 0b11100000, respectively, to indicate that the virtual Ethernet segment operates in sub-Ethernet segment all-active mode or sub-Ethernet segment single-active mode. The ESI tag identifies the virtual Ethernet segment in the advertising PE context. This ESI tag is used to encapsulate broadcast, unknown unicast, or multicast (BUM) traffic for split-horizon filtering.

[0068] 2) Two Ethernet auto-discovery routers corresponding to the sub-Ethernet segments;

[0069] According to one embodiment, each PE device advertises two Ethernet auto-discovery routes corresponding to the sub-Ethernet segment, as well as an ESI label extended community attribute, a router MAC extended community attribute, and a route target extended community attribute.

[0070] The Ethernet auto-discovery route and ESI label extended community attributes corresponding to the sub-Ethernet segment are encoded in accordance with RFC 7432 §8.2.1. The Ethernet Segment Identifier field contains the 10-byte Sub-ESI.

[0071] The ESI tag's extended community attribute is encoded according to RFC 7432 §7.5. The Flags field value is set to 0b11000000 or 0b10100000, indicating whether the sub-Ethernet segment is active or standby, respectively. The ESI tag is used to encapsulate BUM traffic for split horizon filtering.

[0072] It should be noted that the ESI label must identify the virtual Ethernet segment rather than the sub-Ethernet segment in the PE context of the announcement, and its value must be the same as the ESI label value contained in the ESI label extended community attribute announced along with the Ethernet automatic discovery route corresponding to the virtual Ethernet segment.

[0073] The Router MAC extended community attribute is encoded as specified in RFC 9135 §8.1. The Router MAC address is set to the PE-AN link MAC address, coloring the Ethernet Auto-Discovery route for the sub-Ethernet segment. This extended community attribute is used to enable fast convergence in the event of a PE-AN link failure.

[0074] 3) Two packet Ethernet auto-discovery routes corresponding to the PE-AN link;

[0075] According to one embodiment, each PE device advertises two Packet Ethernet Auto-Discovery routes corresponding to the PE-AN link, as well as an ESI label extended community attribute and a route target extended community attribute.

[0076] The packet Ethernet auto-discovery route corresponding to the PE-AN link may be encoded as specified in draft-ietf-bess-evpn-virtual-eth-segment §4.2.1. The Ethernet Segment Identifier field shall contain a Type 3 ESI, the MAC Address field shall contain the PE-AN link MAC address, and the Local Discriminator field shall be set to 0xFFFFFF.

[0077] The ESI tag extended community attribute is encoded as specified in RFC 7432 §7.5, and the Flags field value is 0. To save label space, all packet Ethernet auto-discovery routes advertised by the PE device use the same label value.

[0078] 4) Two Ethernet auto-discovery routes corresponding to the EVPN instance;

[0079] According to one embodiment, each PE device advertises two Ethernet auto-discovered routes corresponding to the EVPN instance, one for each attachment circuit (AC) connected to the same EVPN instance via a different sub-Ethernet segment. These routes are encoded as specified in RFC 7432 §8.4.1 and carry the route target community attribute. The Ethernet segment identifier field shall contain the 10-byte Sub-ESI.

[0080] 5) Multiple MAC / IP announcement routes;

[0081] According to one embodiment, each PE device advertises multiple MAC / IP advertisement routes, one for each customer MAC address learned from a sub-Ethernet segment. These routes are encoded as specified in RFC 7432 §9.2.1 and carry the route target community attribute. The Ethernet Segment Identifier field contains the 10-byte Sub-ESI.

[0082] 6) an inclusive multicast Ethernet label routing;

[0083] According to one embodiment, each PE device advertises an inclusive multicast Ethernet label route along with a Provider Multicast Service Interface Tunnel attribute and a route target extended community attribute. The route is encoded in accordance with RFC 7432 §11.

[0084] 7) Two Ethernet segment routing;

[0085] According to one embodiment, each PE device advertises two Ethernet segment routes, as well as the ES-Import route target extended community attribute, the Designated Forwarder (DF) selection extended community attribute, and the router MAC extended community attribute, each for a different 14-byte globally unique EVC ID.

[0086] Ethernet segment routes are encoded as specified in RFC 7432 §7.4. The Ethernet segment identifier field contains the 10-byte Sub-ESI.

[0087] The ES-Import route target extended community attribute is encoded as specified in §7.6 of RFC 7432. The 6-byte ES-Import route target value is the same as the value of the most significant 6 bytes of the Ethernet Segment Identifier field of the Ethernet Segment Route.

[0088] DF selects the extended community attribute to be encoded as specified in RFC 8584 §2.2.

[0089] The Router MAC extended community attribute is encoded according to RFC 9135 §8.1. The Router MAC field contains the PE-AN link MAC address. This extended attribute is used to support fast convergence when the PE-AN link fails.

[0090] Maintains the virtual Ethernet segment forwarding state table in all PE devices

[0091] According to one embodiment, the method further comprises step S2.

[0092] In step S2, the PE device maintains a virtual Ethernet segment forwarding state table locally to track the forwarding state of each Ethernet virtual circuit included in all virtual Ethernet segments.

[0093] The PE device refers to the forwarding state table when performing DF selection. The remote PE device also refers to the forwarding state table when performing load balancing among all active Ethernet virtual circuits in the virtual Ethernet segment.

[0094] Continue to refer to Figure 2 In the network system shown, each entry in the virtual Ethernet segment forwarding state table shall maintain the following information corresponding to the virtual Ethernet segment:

[0095] vESI

[0096] Sub-ES-single-active-flag

[0097] Sub-ES-ID1

[0098] √primary-flag

[0099] √EVC-ID1

[0100] forwarding-state

[0101] √EVC-ID2

[0102] forwarding-state

[0103] Sub-ES-ID2

[0104] √primary-flag

[0105] √EVC-ID1

[0106] forwarding-state

[0107] √EVC-ID2

[0108] forwarding-state

[0109] vESI is the 10-byte globally unique identifier of the virtual Ethernet segment. Sub-ES-ID1 and Sub-ES-ID2 are the 4-byte sub-Ethernet segment identifiers relative to the vESI (these are the IPv4 addresses of AN1 and AN2, respectively). EVC-ID1 through EVC-ID4 are the 4-byte EVC IDs relative to Sub-ES-ID1 and Sub-ES-ID2 (these are the IPv4 addresses of PE1 and PE2, respectively).

[0110] The sub-ES-single-active-flag is a Boolean value that indicates the sub-mode of the sub-Ethernet segment (TRUE for single-active sub-Ethernet segment mode and FALSE for all-active sub-Ethernet segment mode). The two primary-flags are also Boolean values, indicating whether the corresponding sub-Ethernet segment is the primary or backup sub-Ethernet segment (TRUE for primary and FALSE for backup). The four forwarding-states are also Boolean values ​​that indicate the forwarding state of each EVC (TRUE for "forwarding" or "active" and FALSE for "not forwarding" or "inactive").

[0111] In each entry of the vES forwarding state table, if Sub-ES-single-active-flag is FALSE, the primary-flag of both Sub-ES1 and Sub-ES2 must be TRUE. If Sub-ES-single-active-flag is TRUE, the primary-flag of one of Sub-ES1 and Sub-ES2 must be TRUE, and the other must be FALSE.

[0112] Advertisement of the Ethernet auto-discovery route corresponding to the virtual Ethernet segment, and advertisement / withdrawal of the Ethernet auto-discovery route corresponding to the sub-Ethernet segment and the Ethernet auto-discovery route corresponding to the PE-AN link will trigger the update of the vES forwarding state table.

[0113] Under normal conditions (i.e., the access links and PE-AN links associated with the vES are not faulty), if the vES operates in sub-Ethernet segment all-active mode, the forwarding-state of all EVCs of the vES is TRUE. If the vES operates in sub-Ethernet segment single-active mode, the forwarding-state of all active sub-Ethernet segment EVCs is TRUE, and the forwarding-state of the backup sub-Ethernet segment EVC is FALSE.

[0114] When an access link fails, all PE devices withdraw the Ethernet auto-discovery route for the sub-Ethernet segment corresponding to the failed access link. If the vES operates in sub-Ethernet segment all-active mode, the forwarding-state of all EVCs corresponding to the sub-Ethernet segment of the failed access link is set to FALSE. If the vES operates in sub-Ethernet segment single-active mode, the forwarding-state of all EVCs in the active and backup sub-Ethernet segments is flipped (i.e., TRUE becomes FASLE, and FASLE becomes TRUE).

[0115] If a PE-AN link fails, the PE devices connected to the failed PE-AN link will withdraw the packet Ethernet auto-discovery routes for the failed PE-AN link. This will batch-withdraw all Ethernet auto-discovery routes corresponding to the sub-Ethernet segments that are marked with the MAC address of the failed PE-AN link, causing the forwarding-state of all EVCs carried on the failed PE-AN link to be set to FALSE.

[0116] The following describes the EVPN function configured in the solution of the embodiment of the present application.

[0117] Automatic discovery and DF selection of virtual Ethernet segments

[0118] According to one embodiment, for PE devices connected to the same virtual Ethernet segment, the method includes step S3.

[0119] In step S3, the PE device discovers other PE devices connected to the same virtual Ethernet segment by sending and receiving EVPN Ethernet segment routes, and selects a designated forwarder (DF).

[0120] To distinguish different EVCs connected to the same virtual Ethernet segment of the same PE device, the Ethernet segment routes advertised in the CloudCO scenario must contain the Sub-ESI, rather than the vESI, in the 10-byte Ethernet segment identifier field.

[0121] Each PE device advertises two Ethernet segment routes, each with a different 14-byte globally unique EVC ID, along with the ES-Import route target extended community attribute and the DF selection extended community attribute (as well as the router MAC extended community attribute). The ES-Import field in the ES-Import route target extended community attribute is copied from the most significant 6 bytes of the Ethernet segment identifier field in the Ethernet segment route. Each PE device must also install an input filter for the ES-Import route target value.

[0122] By advertising two Ethernet segment routes and importing two Ethernet segment routes, each PE device can discover the IPv4 addresses of other PE devices connected to the same virtual Ethernet segment and select a DF for the virtual Ethernet segment.

[0123] The DF selection process can be triggered by advertising / withdrawing Ethernet segment routes or withdrawing Ethernet auto-discovered routes corresponding to PE-AN links.

[0124] Before performing DF selection, each PE device needs to refer to the virtual Ethernet segment forwarding state table described above and exclude EVC IDs with forwarding-state set as FALSE from the DF candidate set.

[0125] The PE device selects a DF by performing the following steps: constructing a DF candidate set based on all EVPN Ethernet segment routes related to the virtual Ethernet segment, the DF candidate set including multiple Ethernet virtual circuit identifiers; and then selecting a DF from the DF candidate set based on a predetermined DF selection algorithm.

[0126] exist Figure 2In the CloudCO scenario shown, the DF candidate set corresponding to a virtual Ethernet segment contains 4 EVC IDs, each of which is 8 bytes.<AN IPv4地址,PE IPv4地址> Concatenation. Each PE device constructs a DF candidate set for a virtual Ethernet segment based on all Ethernet segment routes associated with the virtual Ethernet segment. The DF candidate set consists of four 8-byte EVC IDs. Each 8-byte EVC ID is obtained by concatenating the lowest 4 bytes of the Ethernet segment identification field of an Ethernet segment route (i.e., the AN IPv4 address) and the originating router IP address field value (i.e., the PE IPv4 address).

[0127] According to one embodiment, the DF candidate set construction and DF selection method can be indicated by a specific value "DF_Alg_SUB_ESED" in the DFAlg field of the DF selection extended community attribute. This specific value "DF_Alg_SUB_ESED" can be configured locally on the PE device or assigned by the Internet Assigned Numbers Authority in the "DF Alg" subregistry of the "Border Gateway Protocol Extended Community Attribute" registry.

[0128] DF selection can adopt standard methods, such as the service carving method described in RFC 7432 §8.5 or the highest random weight method described in RFC 8584 §3.2, and fine-tune them through the value of the DF selection extended community bitmap field.

[0129] Fast convergence

[0130] According to one embodiment, the method comprises step S4.

[0131] In step S4, if the access link between the access protection group and the AN device fails, or the PE-AN link between the AN device and the PE device fails, the PE device triggers the rapid convergence process by withdrawing the Ethernet automatic discovery route of the sub-Ethernet segment corresponding to the faulty access link, or the packet Ethernet automatic discovery route of the faulty PE-AN link.

[0132] Specifically, the PE device should announce the Ethernet auto-discovery routes and Ethernet segment routes corresponding to the sub-Ethernet segment, and carry the router MAC extended community attribute (and other extended community attributes) to color the Ethernet auto-discovery routes and Ethernet segment routes of the sub-Ethernet segment (the color is the PE-AN link MAC address).

[0133] The remote PE device imports the Ethernet auto-discovery routes for the colored sub-Ethernet segments. When the remote PE device receives a withdrawal message for the packet Ethernet auto-discovery routes corresponding to the PE-AN link, based on the withdrawal message, the remote PE device derives a list of all Ethernet auto-discovery routes for the sub-Ethernet segments that are colored (i.e., the MAC address of the failed PE-AN link). The remote PE device then performs a withdrawal process for the Ethernet auto-discovery routes for the sub-Ethernet segments in the list.

[0134] The PE devices that make up the PE redundancy group import colored Ethernet segment routes (the color represents the MAC address of the PE-AN link). When the PE device receives a withdrawal message for the Packet Ethernet Auto-Discovery route corresponding to the PE-AN link, based on the withdrawal message, the remote PE device derives a list of all Ethernet segment routes that are colored (i.e., the MAC address of the failed PE-AN link). The PE device then performs a withdrawal process for the Ethernet segment routes in the list.

[0135] Split Horizon Filtering

[0136] Different from the horizontal split filtering function described in RFC 7432 §8.3, according to the embodiment of the present application, the PE devices constituting the PE redundancy group shall not flood the BUM traffic received from one sub-Ethernet segment to other sub-Ethernet segments of the same virtual Ethernet segment; for the virtual Ethernet segment and its various sub-Ethernet segments, the ESI labels in the ESI label extended community attributes carried by all the Ethernet automatic discovery routes announced for the virtual Ethernet segment or its sub-Ethernet segments must be the same. The ESI label identifies the virtual Ethernet segment in the PE device context, rather than the sub-Ethernet segment; the PE devices constituting the PE redundancy group must use the same ESI label to mark the various sub-Ethernet segments of the same virtual Ethernet segment, so that the received BUM traffic encapsulated with the same ESI label will not be flooded to other sub-Ethernet segments of the virtual Ethernet segment.

[0137] Load balancing and protection switching

[0138] According to one embodiment, the method comprises step S5.

[0139] In step S4, when the remote PE device sends a data packet to a client MAC address of a virtual Ethernet segment, the remote PE device should perform load balancing among all active Ethernet virtual circuits of the virtual Ethernet segment.

[0140] Specifically, under normal conditions (i.e., the access protection group access link and the PE-AN link are fault-free), if the virtual Ethernet segment operates in the sub-Ethernet segment full-active mode, the remote PE device performs load balancing among all Ethernet virtual circuits of the virtual Ethernet segment; if the virtual Ethernet segment operates in the sub-Ethernet segment single-active mode, the remote PE device performs load balancing among the Ethernet virtual circuits of the active sub-Ethernet segment, and uses the Ethernet virtual circuits of the backup sub-Ethernet segment as the backup path.

[0141] Troubleshooting

[0142] 1) Access link fault handling

[0143] When each PE device in a redundant PE group receives notification of an access link failure, it withdraws the Ethernet auto-discovery route for the sub-Ethernet segment corresponding to the failed access link. Upon receiving a withdrawal message for the Ethernet auto-discovery route for a sub-Ethernet segment from each PE device in the redundant PE group, the remote PE device updates its local virtual Ethernet segment forwarding state table accordingly. If the virtual Ethernet segment is operating in sub-Ethernet segment all-active mode, the remote PE device performs load balancing among the still-active Ethernet virtual circuits in the virtual Ethernet segment. If the virtual Ethernet segment is operating in sub-Ethernet segment single-active mode, the remote PE device switches to load balancing among the Ethernet virtual circuits in the backup sub-Ethernet segment of the virtual Ethernet segment.

[0144] 2) PE-AN link fault handling

[0145] When a PE device in a redundant PE group detects a PE-AN link failure, it withdraws the packet Ethernet auto-discovery route for the failed PE-AN link. Upon receiving this route withdrawal message, the remote PE device batch-withdraws the Ethernet auto-discovery routes for the colored sub-Ethernet segments (the color represents the MAC address of the failed PE-AN link), thereby batch-withdrawing all customer MAC addresses and ACs associated with the withdrawn sub-Ethernet segments. The remote PE device updates its virtual Ethernet segment forwarding state table and MAC-VRF accordingly. It then performs load balancing across the remaining active Ethernet virtual circuits in the virtual Ethernet segment.

[0146] The method of the embodiment of the present application provides a new redundant protection mode for EVPN multi-homing connections, which is applicable to the scenario of redundant access of multiple chassis in CloudC. The method also provides redundant mode coding, ESI coding, and EVPN route coding involved in supporting the redundant protection mode of EVPN multi-homing connections, and describes various EVPN multi-homing connection functions, thereby better adapting to the scenario of redundant access of multiple chassis in CloudCO.

[0147] Figure 3A structural diagram of a multi-chassis access protection device for EVPN services according to an embodiment of the present application is shown.

[0148] The multi-chassis access protection device is included in each PE device.

[0149] The device includes a device for configuring a multi-chassis redundant access mode for an EVPN service (hereinafter referred to as "mode configuration device 1").

[0150] Reference Figure 3 The mode configuration device 1 configures a multi-chassis redundant access mode for an EVPN service.

[0151] The multi-chassis redundant access mode is applicable to a scenario where an access protection group is multi-homed to two or more AN devices connected to CloudCO, and the two or more AN devices are dual-homed to the same pair of PE devices.

[0152] The access protection group generally refers to client devices or networks using various dual-homing access technologies, such as a link aggregation group, an Ethernet linear protection group, or an ITU-T Type B / Type C or IEEE trunk / tree passive optical network protection group.

[0153] If an access protection group is multi-homed to two AN devices connected to CloudCO, the access protection group corresponds to a virtual Ethernet segment on the PE device, which contains four Ethernet virtual circuits carried on the four physical Ethernet links connecting the PE and AN. This virtual Ethernet segment is further divided into two sub-Ethernet segments, each containing two different Ethernet virtual circuits, each corresponding to an access link of the access protection group.

[0154] Among them, in the multi-frame redundant access mode, the virtual Ethernet segment corresponding to an access protection group can be divided into two or more sub-Ethernet segments; the virtual Ethernet segment can operate in the sub-Ethernet segment full-active mode or the sub-Ethernet segment single-active mode; each sub-Ethernet segment can be set as the main sub-Ethernet segment or the backup sub-Ethernet segment.

[0155] If the virtual Ethernet segment works in the sub-Ethernet segment all-active mode, then each of its corresponding sub-Ethernet segments is the active sub-Ethernet segment; if the virtual Ethernet segment works in the sub-Ethernet segment single-active mode, then one of the sub-Ethernet segments is the active sub-Ethernet segment, and the other sub-Ethernet segments are backup sub-Ethernet segments.

[0156] The device according to the embodiment of the present application adopts an encoding method of virtual Ethernet segment identifier (vESI), sub-Ethernet segment identifier (Sub-ESI) and Ethernet virtual circuit identifier (EVC ID) that is compatible with the standard EVPN routing encoding format.

[0157] In the multi-chassis redundant access mode, the apparatus advertises the following EVPN routes for a virtual Ethernet segment corresponding to an access protection group:

[0158] 1) An Ethernet auto-discovery route corresponding to the virtual Ethernet segment;

[0159] 2) Two Ethernet auto-discovery routers corresponding to the sub-Ethernet segments;

[0160] 3) Two packet Ethernet auto-discovery routes corresponding to the PE-AN link;

[0161] 4) Two Ethernet auto-discovery routes corresponding to the EVPN instance;

[0162] 5) Multiple MAC / IP announcement routes;

[0163] 6) an inclusive multicast Ethernet label routing;

[0164] 7) Two Ethernet segment routing.

[0165] According to one embodiment, the device includes a device (hereinafter referred to as "state maintaining device") for locally maintaining a virtual Ethernet segment forwarding state table to track the forwarding states of all Ethernet virtual circuits included in all virtual Ethernet segments.

[0166] The state maintenance device of the PE device maintains the virtual Ethernet segment forwarding state table locally to track the forwarding state of each Ethernet virtual circuit included in all virtual Ethernet segments.

[0167] According to one embodiment, the apparatus includes a device for discovering other PE devices connected to the same virtual Ethernet segment by sending and receiving EVPN Ethernet segment routes, and selecting a designated forwarder (DF) (hereinafter referred to as "DF selection device").

[0168] For PE devices connected to the same virtual Ethernet segment, the DF selection device discovers other PE devices connected to the same virtual Ethernet segment by sending and receiving EVPN Ethernet segment routes, and selects a DF.

[0169] Specifically, the DF selection device constructs a DF candidate set based on all EVPN Ethernet segment routes related to the virtual Ethernet segment, where the DF candidate set includes multiple Ethernet virtual circuit identifiers; then, based on a predetermined DF selection algorithm, selects a DF from the DF candidate set.

[0170] According to one embodiment, the apparatus comprises means for triggering a fast convergence procedure (hereinafter "fault protection means") by withdrawing the Ethernet auto-discovery route of the sub-ethernet segment corresponding to the failed access link between the access protection group and the AN device, or the packet Ethernet auto-discovery route of the failed PE-AN link, if the access link between the access protection group and the AN device fails, or the PE-AN link between the AN device and the PE device fails.

[0171] The fault protection means triggers a fast convergence procedure by withdrawing the Ethernet auto-discovery route of the sub-ethernet segment corresponding to the failed access link between the access protection group and the AN device, or the packet Ethernet auto-discovery route of the failed PE-AN link, if the access link between the access protection group and the AN device fails, or the PE-AN link between the AN device and the PE device fails.

[0172] According to one embodiment, the apparatus comprises means for load balancing among all active Ethernet virtual circuits of the virtual Ethernet segment (hereinafter "load balancing means").

[0173] The load balancing means of the remote PE device load balances among all active Ethernet virtual circuits of the virtual Ethernet segment when the remote PE device sends a packet to the customer MAC address associated with the virtual Ethernet segment.

[0174] In particular, under normal conditions (i.e. no failure of the access links and PE-AN links related to the access protection group), if the virtual Ethernet segment operates in the sub-ethernet segment all-live mode, the load balancing means load balances among all Ethernet virtual circuits of the virtual Ethernet segment; if the virtual Ethernet segment operates in the sub-ethernet segment single-live mode, the load balancing means load balances among the Ethernet virtual circuits of the primary sub-ethernet segment and uses the Ethernet virtual circuits of the standby sub-ethernet segment as standby paths.

[0175] When the PE devices of the redundant PE group receive the notification of the access link failure, they withdraw the Ethernet auto-discovery route of the sub-ethernet segment corresponding to the failed access link, respectively. The state maintenance means of the remote PE device updates the local virtual Ethernet segment forwarding state table accordingly when it receives the Ethernet auto-discovery route withdrawal messages of the sub-ethernet segments from the PE devices of the redundant PE group. If the virtual Ethernet segment operates in the sub-ethernet segment all-live mode, the load balancing means of the remote PE device load balances among the still active Ethernet virtual circuits of the virtual Ethernet segment; if the virtual Ethernet segment operates in the sub-ethernet segment single-live mode, the load balancing means of the remote PE device switches to load balance among the Ethernet virtual circuits of the standby sub-ethernet segment of the virtual Ethernet segment.

[0176] When a PE device in a redundant PE group detects a PE-AN link failure, it withdraws the packet Ethernet auto-discovery route for the failed PE-AN link. Upon receiving this route withdrawal message, the remote PE device batch-withdraws the Ethernet auto-discovery routes for the colored sub-Ethernet segments (the color represents the MAC address of the failed PE-AN link), thereby batch-withdrawing all customer MAC addresses and ACs associated with the withdrawn sub-Ethernet segments. The remote PE device's state maintenance device updates its virtual Ethernet segment forwarding state table and MAC-VRF accordingly. The remote PE device's load balancing device then performs load balancing among the remaining active Ethernet virtual circuits in the virtual Ethernet segment.

[0177] The apparatus of the embodiment of the present application provides a new redundant protection mode for EVPN multi-homing connections, which is applicable to scenarios where CloudCO multi-chassis redundant access is required. The apparatus also provides redundant mode coding, ESI coding, and EVPN route coding involved in supporting the redundant protection mode for EVPN multi-homing connections, and describes various EVPN multi-homing connection functions, thereby better adapting to scenarios where CloudCO multi-chassis redundant access is required.

[0178] The software program of the embodiment of the present application can be executed by a processor to implement the steps or functions described above. Similarly, the software program of the present invention (including related data structures) can be stored in a computer-readable recording medium, such as a RAM memory, a magnetic or optical drive, or a floppy disk and similar devices. In addition, some steps or functions of the present invention can be implemented using hardware, such as a circuit that cooperates with a processor to perform each function or step.

[0179] In addition, a portion of the present invention may be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. The program instructions for calling the method of the present invention may be stored in a fixed or removable recording medium, and / or transmitted through a data stream in a broadcast or other signal-carrying medium, and / or stored in a working memory of a computer device that operates according to the program instructions. Here, according to one embodiment of the present invention, a device is included, which includes a memory for storing computer program instructions and a processor for executing the program instructions, wherein, when the computer program instructions are executed by the processor, the device is triggered to operate based on the aforementioned methods and / or technical solutions according to multiple embodiments of the present invention.

[0180] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any figure marks in the claims should not be regarded as limiting the claims involved. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices stated in the system claim may also be implemented by one unit or device through software or hardware. Words such as first, second, etc. are used to indicate names and do not indicate any particular order.

Claims

1. A multi-chassis access protection method for EVPN services, wherein: The method comprises: Configure a multi-chassis redundant access mode for EVPN services. The multi-chassis redundant access mode is applicable to a scenario where an access protection group is multi-homed to two or more access node AN devices of a cloud central office CloudCO, and these two or more AN devices are dual-homed to the same pair of PE devices. The method adopts an encoding method of virtual Ethernet segment identifier, sub-Ethernet segment identifier and Ethernet virtual circuit identifier that is compatible with the standard EVPN routing encoding format. To support the multi-chassis redundant access mode, the method defines three new bits in the Flags field of the ESI label extended community attribute, and defines four Flags field values ​​to indicate whether the virtual Ethernet segment operates in the sub-Ethernet segment full-active or single-active mode, and whether the sub-Ethernet segment is the primary or backup sub-Ethernet segment.

2. According to the method described in claim 1, in the multi-frame redundant access mode, the virtual Ethernet segment corresponding to an access protection group can be divided into two or more sub-Ethernet segments; the virtual Ethernet segment can operate in the sub-Ethernet segment full-active mode or the sub-Ethernet segment single-active mode; each sub-Ethernet segment can be set as the main sub-Ethernet segment or the backup sub-Ethernet segment respectively.

3. The method according to claim 1 or 2, wherein: The method comprises: In the multi-chassis redundant access mode, each PE device advertises the following EVPN routes for the virtual Ethernet segment corresponding to an access protection group: an Ethernet auto-discovery route corresponding to the virtual Ethernet segment; Two Ethernet auto-discovery routes corresponding to the sub-Ethernet segments; Two corresponding to the packet Ethernet automatic discovery routing of the PE-AN link; Two Ethernet auto-discovery routes corresponding to the EVPN instance; Multiple MAC / IP advertising routes; an inclusive multicast Ethernet label routing; Two Ethernet segment routing.

4. The method according to claim 1 or 2, wherein: The method comprises: The PE device maintains a virtual Ethernet segment forwarding state table locally to track the forwarding state of each Ethernet virtual circuit contained in all virtual Ethernet segments.

5. The method according to claim 1 or 2, wherein: For PE devices connected to the same virtual Ethernet segment, the method includes: By sending and receiving EVPN Ethernet segment routes, it discovers other PE devices connected to the same virtual Ethernet segment and selects a designated forwarder (DF).

6. The method according to claim 5, wherein: The method comprises: Constructing a DF candidate set based on all EVPN Ethernet segment routes related to the virtual Ethernet segment, the DF candidate set including multiple Ethernet virtual circuit identifiers; Based on a predetermined DF selection algorithm, a DF is selected from the DF candidate set.

7. The method according to claim 1 or 2, wherein: The method comprises: If the access link between the access protection group and the AN device fails, or the PE-AN link between the AN device and the PE device fails, the PE device triggers the rapid convergence process by withdrawing the Ethernet automatic discovery route of the sub-Ethernet segment corresponding to the failed access link, or the packet Ethernet automatic discovery route of the failed PE-AN link.

8. The method according to claim 1 or 2, wherein: The method comprises: When a remote PE device sends a data packet to a customer MAC address associated with a virtual Ethernet segment, the remote PE device performs load balancing among all active Ethernet virtual circuits in the virtual Ethernet segment.

9. A multi-chassis access protection device for EVPN services, wherein: The device comprises: A device for configuring a multi-chassis redundant access mode for an EVPN service; The multi-chassis redundant access mode is applicable to a scenario where an access protection group is multi-homed to two or more AN devices connected to CloudCO, and these two or more AN devices are dual-homed to the same pair of PE devices. Among them, an encoding method of virtual Ethernet segment identifier, sub-Ethernet segment identifier and Ethernet virtual circuit identifier compatible with the standard EVPN routing encoding format is adopted. In order to support the multi-chassis redundant access mode, three new bits are defined in the Flags field of the ESI label extended community attribute, and 4 Flags field values ​​are defined to indicate whether the virtual Ethernet segment works in the sub-Ethernet segment full-active or single-active mode, and whether the sub-Ethernet segment is the main or backup sub-Ethernet segment.

10. According to the device according to claim 9, in the multi-frame redundant access mode, the virtual Ethernet segment corresponding to an access protection group can be divided into two or more sub-Ethernet segments; the virtual Ethernet segment can operate in the sub-Ethernet segment full-active mode or the sub-Ethernet segment single-active mode; each sub-Ethernet segment can be set as the main sub-Ethernet segment or the backup sub-Ethernet segment respectively.

11. A PE device for multi-chassis access protection of EVPN services, wherein: The PE device includes a processor and a memory, wherein the memory stores a computer program. When the computer program is executed by the processor, the following steps are implemented: Configure a multi-chassis redundant access mode for EVPN services. The multi-chassis redundant access mode is applicable to a scenario where an access protection group is multi-homed to two or more AN devices connected to CloudCO, and these two or more AN devices are dual-homed to the same pair of PE devices. Among them, an encoding method of virtual Ethernet segment identifier, sub-Ethernet segment identifier and Ethernet virtual circuit identifier compatible with the standard EVPN routing encoding format is adopted. In order to support the multi-chassis redundant access mode, three new bits are defined in the Flags field of the ESI label extended community attribute, and 4 Flags field values ​​are defined to indicate whether the virtual Ethernet segment works in the sub-Ethernet segment full-active or single-active mode, and whether the sub-Ethernet segment is the main or backup sub-Ethernet segment.

12. A computer-readable storage medium having a computer program stored therein, the computer program being used in a PE device for multi-chassis access protection of an EVPN service; When the computer program is executed by a PE device, the following steps are performed: Configure a multi-chassis redundant access mode for EVPN services. in, The multi-chassis redundant access mode is applicable to scenarios where an access protection group is multi-homed to two or more AN devices connected to CloudCO, and these two or more AN devices are dual-homed to the same pair of PE devices; Among them, an encoding method of virtual Ethernet segment identifier, sub-Ethernet segment identifier and Ethernet virtual circuit identifier compatible with the standard EVPN routing encoding format is adopted. In order to support the multi-chassis redundant access mode, three new bits are defined in the Flags field of the ESI label extended community attribute, and 4 Flags field values ​​are defined to indicate whether the virtual Ethernet segment works in the sub-Ethernet segment full-active or single-active mode, and whether the sub-Ethernet segment is the main or backup sub-Ethernet segment.

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