Df election mode switching method, information sending method, pe device, medium

Abstract

The application provides a DF election mode switching method and information sending method, which comprises the following steps: in response to receiving a first route announcement message issued by a second PE for a second sub-interface failure, a first PE switches a DF election mode to a first mode; in response to receiving a first route revocation message issued by the second PE for a second sub-interface recovery, the first PE switches the DF election mode from the first mode to a second mode. In the application, the DF election is switched to the first mode only when there is a sub-interface failure on a certain <ESI, EVI>, and routes corresponding to the sub-interfaces with failures are needed to be issued, while routes corresponding to the sub-interfaces without failures do not need to be issued. Since the number of the sub-interfaces with failures is far less than the number of the sub-interfaces without failures, the number of the routes needed to be issued in the first mode is reduced in quantity, and in the second mode, routes corresponding to the sub-interfaces do not need to be issued, so that the system overhead is reduced and the network resources are saved.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a method for switching a Designated Forwarder (DF) election mode, an information transmission method, a Provider Edge (PE) device, and a computer-readable medium in Ethernet Virtual Private Network (EVPN) technology. Background Technology

[0002] In EVPN technology, the DF election mode influenced by the sub-interface access circuit (AC, Attachment Circuit) (hereinafter referred to as AC-DF mode, and the opposite as non-AC-DF mode) aims to ensure that when the primary interface is not failed, but its sub-interface fails, the Ethernet Segment Identifier (ESI) and EVPN Instance (EVI) corresponding to that sub-interface are selected.<ESI,EVI> In the DF election within the scope of (indicated by) the sub-interface, this sub-interface is excluded, thereby avoiding this<ESI,EVI> The DF election result is abnormal. This AC-DF mode relies on EVI-based Ethernet Auto-Discovery per EVIroute, and if a certain<ESI,EVI> No EVI-based Ethernet auto-discovery routes have been published on the platform.<ESI,EVI> The DF election will be abnormal, regardless of whether there is a PE node.<ESI,EVI> Faulty sub-interfaces will cause problems due to abnormal DF election.

[0003] There exists a mechanism that leverages DF election extension group attributes to negotiate whether the DF election mode is an AC-DF mode; however, this negotiation mechanism is based on ESI granularity, not...<ESI,EVI> At the granular level, once negotiated to AC-DF mode at the ESI granularity, all of that ESI...<ESI,EVI> All servers must publish EVI-based Ethernet auto-discovery routes; otherwise, no EVI-based Ethernet auto-discovery routes will be published.<ESI,EVI> The election results on DF will be abnormal.

[0004] Since this AC-DF mode relies on EVI-based Ethernet auto-discovery routing, and in some EVPN scenarios, such as Provider Backbone Bridge (PBB) EVPN scenarios, which do not normally use EVI-based Ethernet auto-discovery routing, it would be a waste to add corresponding EVI-based Ethernet auto-discovery routes to all ESI sub-interfaces simply for the purpose of DF election affected by AC, which would be a waste for scenarios such as PBB EVPN that do not normally use EVI-based Ethernet auto-discovery routing. Summary of the Invention

[0005] This invention provides a DF election mode switching method, an information transmission method, a PE device, and a computer-readable medium.

[0006] In a first aspect, the present invention provides a method for switching a designated forwarder (DF) election mode, used in a first provider network edge (PE), where both the first PE and a second PE are on a first Ethernet segment (ES). The first PE has a first sub-interface, and the second PE has a second sub-interface corresponding to the first sub-interface. Both the first and second sub-interfaces are bound to a first Ethernet Virtual Private Network (EVI), and both the first and second sub-interfaces are sub-interfaces on the first ES. The method includes:

[0007] In response to receiving the first route advertisement message published by the second PE, the DF election mode corresponding to the first sub-interface is switched to the first mode, which is the DF election mode in which no Ethernet segmented route published by the second PE for the first ES participates;

[0008] In response to receiving the first route withdrawal message published by the second PE, the DF election mode is switched from the first mode to the second mode, which is the DF election mode in which the Ethernet segmented route published by the second PE for the first ES participates;

[0009] The first route is a route advertised by the second PE in response to a change in the state of the second subinterface; the first route advertisement message is a route advertisement message carrying multi-protocol network layer reachability information MP_REACH_NLRI advertised by the second PE in response to a change in the state of the second subinterface when the second subinterface fails; the first route cancellation message is a route cancellation message carrying multi-protocol network layer unreachability information MP_UNREACH_NLRI advertised by the second PE in response to a change in the state of the second subinterface when the second subinterface recovers.

[0010] In some embodiments, it also includes:

[0011] In response to receiving the first route advertisement message published by the second PE and the first sub-interface being in normal status, a route advertisement message indicating that the first sub-interface is in normal status is published for the first sub-interface.

[0012] In some embodiments, prior to receiving the first route advertisement message published by the second PE, the method further includes:

[0013] In response to receiving an Ethernet segmented route carrying first indication information published by the second PE, each of the first ES...<ESI,EVI> The DF election mode on the screen is set to the second mode;

[0014] The first indication information is the indication information published when the PE is able to publish and receive the first route.

[0015] In some embodiments,

[0016] In response to receiving the first route advertisement message published by the second PE, switching the DF election mode corresponding to the first sub-interface to the first mode includes: in response to receiving the first route advertisement message published by the second PE, switching the DF election mode to the first mode only when all the Ethernet segment routes of the first ES carry the first indication information;

[0017] In response to receiving a first route revocation message published by the second PE, switching the DF election mode from the first mode to the second mode includes: in response to receiving a first route revocation message published by the second PE, switching the DF election mode from the first mode to the second mode only when all received Ethernet segment routes of the first ES carry the first indication information;

[0018] The first indication information is the indication information published when the PE is able to publish and receive the first route.

[0019] In some embodiments, the second PE also has an EVPN neighbor relationship with the third PE, and none of the sub-interfaces of the third PE are on the first ES; the method further includes:

[0020] The third PE responds to the first route advertisement message published by the second PE, which specifies the first ES as the route target, and if the third PE does not have an ES matching the route target locally, by filtering the first route advertisement message.

[0021] Secondly, the present invention provides an information transmission method for a second provider network edge (PE), wherein both the second PE and the first PE are on a first Ethernet segment (ES). The first PE is configured with a first sub-interface, and the second PE is configured with a second sub-interface corresponding to the first sub-interface. Both the first and second sub-interfaces are bound to a first Ethernet Virtual Private Network (EVI) instance, and both the first and second sub-interfaces are sub-interfaces on the first ES. The method includes:

[0022] In response to the failure of the second sub-interface, publish the first route announcement message;

[0023] In response to the second sub-interface returning to normal, a message indicating the cancellation of the first route is published.

[0024] The first route is a route advertised by the second PE in response to a change in the state of the second subinterface; the first route advertisement message is a route advertisement message carrying multi-protocol network layer reachability information MP_REACH_NLRI advertised by the second PE in response to a change in the state of the second subinterface when the second subinterface fails; the first route cancellation message is a route cancellation message carrying multi-protocol network layer unreachability information MP_UNREACH_NLRI advertised by the second PE in response to a change in the state of the second subinterface when the second subinterface recovers.

[0025] In some embodiments, it also includes:

[0026] Before publishing the first route advertisement message, the first indication information is carried in the published Ethernet segmented route;

[0027] The first indication information is the indication information published when the PE is able to publish and receive the first route.

[0028] In some embodiments, in response to the failure of the second sub-interface, publishing a first routing advertisement message includes:

[0029] In response to the failure of the second sub-interface, the first route advertisement message will only be published to the neighbor if the first indication information is carried in all Ethernet segment routes published by the PE.

[0030] The first indication information is the indication information published when the PE is able to publish and receive the first route.

[0031] Furthermore, it also includes:

[0032] In response to the failure of the second sub-interface, the Multiprotocol Label (MPLS) Label field in the first routing advertisement message is set to a reserved value, and the Ethernet TagID field in the first routing advertisement message is set to the I-Component Service Identifier (I-SID) value corresponding to the first EVI. The routing target of the first backbone component (B-Component) is carried in the first routing advertisement message, wherein the first backbone component is the backbone component bound to the first EVI.

[0033] In some embodiments, it also includes:

[0034] In response to the failure of the second sub-interface, the first route target corresponding to the first Ethernet segment ES is carried in the first route advertisement message.

[0035] Furthermore, among which:

[0036] The first routing target's constraint mechanism on the routing target (RT Constraints) is visible.

[0037] Furthermore, among which:

[0038] The first route target is used to allow PE nodes that are not on the first ES to filter the first route advertisement messages.

[0039] In some embodiments, it also includes:

[0040] In response to the failure of the second sub-interface, the first route advertisement message published carries the second route target corresponding to the first EVI, and the second route target is not visible to the route target constraint RT Constraints mechanism.

[0041] Thirdly, the present invention provides a provider network edge PE device, comprising:

[0042] One or more processors;

[0043] A memory that stores one or more programs, which, when executed by one or more processors, enable the one or more processors to implement any of the above-described DF election mode switching methods or information transmission methods.

[0044] One or more I / O interfaces are connected between the processor and the memory and configured to enable information interaction between the processor and the memory.

[0045] Fourthly, the present invention provides a computer-readable medium having a computer program stored thereon, wherein the program, when executed by a processor, implements any of the above-described DF election mode switching methods or information transmission methods.

[0046] The DF election mode switching method provided by this invention, when each<ESI,EVI> The initial DF election mode is mode two, which does not require the publication of EVI-based Ethernet auto-discovery routes; it only occurs when a certain...<ESI,EVI> When a sub-interface fault does indeed exist, this<ESI,EVI> The DF election mode on the device was then switched to the first mode. At this time, the...<ESI,EVI> Only then does it require route advertising of a scale commensurate with the number of sub-interfaces that have failed, each<ESI,EVI> Each enters the first mode. When<ESI,EVI> When there are no faults, both the first and second modes of DF election can produce correct results. The second mode will reduce the number of routes that need to be published by orders of magnitude, thereby reducing system overhead and saving network resources, and thus has better performance. Attached Figure Description

[0047] Figure 1 This is a flowchart illustrating a DF election mode switching method provided by the present invention;

[0048] Figure 2 This is a flowchart illustrating some steps in another DF election mode switching method provided by the present invention.

[0049] Figure 3 This is a flowchart illustrating some steps in another DF election mode switching method provided by the present invention.

[0050] Figure 4 This is a flowchart illustrating some steps in another DF election mode switching method provided by the present invention.

[0051] Figure 5 This is a flowchart illustrating some steps in another DF election mode switching method provided by the present invention.

[0052] Figure 6 This is a flowchart illustrating some steps in another DF election mode switching method provided by the present invention.

[0053] Figure 7 This is a schematic diagram of an information sending method provided by the present invention;

[0054] Figure 8 This is a flowchart illustrating some steps in another information sending method provided by the present invention;

[0055] Figure 9 This is a flowchart illustrating some steps in another information sending method provided by the present invention;

[0056] Figure 10 This is a flowchart illustrating some steps in another information sending method provided by the present invention;

[0057] Figure 11 This is a flowchart illustrating some steps in another information sending method provided by the present invention;

[0058] Figure 12 This is a flowchart illustrating some steps in another information sending method provided by the present invention;

[0059] Figure 13 This is a schematic diagram of a specific DF election mode switching application scenario provided by the present invention;

[0060] Figure 14 This is a schematic diagram of a PE device provided by the present invention;

[0061] Figure 15 This is a schematic diagram of a computer-storable medium provided by the present invention; Detailed Implementation

[0062] To enable those skilled in the art to better understand the technical solutions of the present invention, a detailed description is provided below in conjunction with the accompanying drawings and specific embodiments.

[0063] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and that those skilled in the art will fully understand the scope of the invention.

[0064] Where there is no conflict, the various embodiments of the present invention and the features thereof may be combined with each other.

[0065] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0066] The terminology used herein is for describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded.

[0067] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art and the invention, and will not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0068] In a basic network scenario of this embodiment, the first PE and the second PE are dual-homed to the same user network edge CE. The first PE is configured with a first sub-interface, and the second PE is configured with an interface connected to the first sub-interface.<ESI,EVI> The corresponding second sub-interface. When the state of the second sub-interface changes, the corresponding first PE is triggered.<ESI,EVI> The operation of switching the DF election mode.

[0069] In a first aspect, embodiments of this disclosure provide a DF election mode switching method for a first PE, such as... Figure 1 As shown, it includes the following steps:

[0070] S100: In response to receiving the first route advertisement message published by the second PE, switch the DF election mode corresponding to the first sub-interface to the first mode.

[0071] The first mode is the DF election mode in which no second PE participates in the Ethernet segmentation route published by the first ES.

[0072] Both the first sub-interface and the second sub-interface are bound to the first EVI, and both the first sub-interface and the second sub-interface are sub-interfaces on the first ES.

[0073] The first route advertisement message is a route advertisement message carrying multi-protocol network layer reachability information MP_REACH_NLRI, issued by the second PE in response to the change in the state of the second sub-interface when the second sub-interface fails.

[0074] After receiving the first route advertisement message, the first PE will determine the corresponding first sub-interface by using the ESI information that identifies the first ES and the information that identifies the first EVI contained in the first route, thereby excluding the Ethernet segmented route advertised by the second PE for the first ES from the DF election process corresponding to the first sub-interface.

[0075] If the second sub-interface fails but the corresponding main interface does not fail, the first mode is used, and the second sub-interface corresponds to...<ESI,EVI> The DF election on the platform will exclude the second sub-interface, thereby avoiding this<ESI,EVI> The DF election result is abnormal. Specifically, excluding the second sub-interface means excluding the Ethernet segmented route sent by the PE node where the second sub-interface resides (i.e., the second PE). It's worth noting that from the perspective of the second PE, the second sub-interface is not directly visible.

[0076] It should be noted that there are many algorithms for DF election, and new DF election algorithms may emerge in the future. These algorithms can be used in both the first and second modes. The final DF election result can only be obtained by combining the first / second mode with a specific DF election algorithm (such as the DF election algorithm in "draft-ietf-bess-evpn-pref-df").

[0077] It should be noted that if the main interface fails, all its sub-interfaces will also fail. In this case, the second PE only needs to cancel the corresponding Ethernet segment route and does not need to issue a first route advertisement message for each sub-interface. Therefore, the first PE can know that the corresponding sub-interface on the corresponding ES on the second PE has failed, but its main interface has not failed, from the first route advertisement message received.

[0078] Therefore, after receiving the first route announcement message published by the second PE, the first PE will...<ESI,EVI> The DF election mode on the screen has switched from mode two to mode one. For example... Figure 1 As shown, the method further includes:

[0079] S200: In response to receiving the first route cancellation message published by the second PE, switch the DF election mode from the first mode to the second mode.

[0080] The second mode is a DF election mode in which the second PE participates in the Ethernet segmented routes published by the first ES.

[0081] The first route cancellation message is a route cancellation message carried by the multi-protocol network layer reachability information MP_UNREACH_NLRI, issued by the second PE in response to the change in the state of the second subinterface when the second subinterface returns to normal.

[0082] After receiving the first route cancellation message, the first PE will determine the corresponding first sub-interface through the ESI information identifying the first ES and the information identifying the first EVI contained in the first route. In this way, the Ethernet segmented route published by the second PE for the first ES will be restored to participate in the DF election process corresponding to the first sub-interface, just as it was before the second sub-interface failed. Therefore, it is called "DF election mode with the participation of the Ethernet segmented route published by the second PE for the first ES".

[0083] exist<ESI,EVI> Within the scope, there may be multiple network elements. If a sub-interface failure occurs on multiple network elements, and each of them publishes a first route advertisement message to its neighbor, then the first PE will receive multiple first route advertisement messages from multiple network elements. Because each first route cancellation message can only cancel one corresponding first route advertisement message, the DF election mode cannot be switched to the second mode directly when the first PE receives only one first route cancellation message. Instead, the DF election mode should only be switched to the second mode after all first route advertisement messages have received their corresponding cancellation messages.

[0084] After receiving the first route cancellation message published by the second PE, the first PE will...<ESI,EVI> The DF election mode is switched to the second mode before step S100.

[0085] Because each<ESI,EVI> The initial DF election mode is mode two, so there is no need to publish Ethernet auto-discovery routes based on EVI. However, when a certain<ESI,EVI> When a sub-interface fault does indeed exist, this<ESI,EVI> The DF election mode on the device was then switched to the first mode. At this time, the...<ESI,EVI> Only then does it require route advertising of a scale commensurate with the number of sub-interfaces that have failed, each<ESI,EVI> Each enters the first mode. When<ESI,EVI> When there are no faults, both the first and second modes can produce correct results in DF election, and the second mode has better performance because it reduces the number of routes that need to be published by orders of magnitude.

[0086] In some embodiments, such as Figure 2 As shown, in response to receiving the first route advertisement message published by the second PE, the following steps are included:

[0087] S101: In response to receiving the first route advertisement message published by the second PE and the first sub-interface being in normal status, publish a route advertisement message for the first sub-interface indicating that the first sub-interface is in normal status.

[0088] It should be noted that before step S101, the first PE does not need to publish a route advertisement message specifically for a certain non-faulty sub-interface to its neighbors for the purpose of DF election, thereby reducing the number of route advertisement messages by a significant margin.

[0089] In scenarios like PBB EVPN, where EVI-based Ethernet auto-discovery routes are not originally published, routes were not obtained through EVI-based Ethernet auto-discovery before switching to the first mode.<ESI,EVI> The sub-interface status information of each network element within the scope. Therefore, when the first PE receives the first routing announcement message from the second PE regarding the failure of the second sub-interface, it needs to perform a first routing announcement.<ESI,EVI> Within the scope, the routing advertisement information for the first subinterface corresponding to the second subinterface on this network element, which is functioning normally, is resent to the EVPN neighbors. This routing advertisement information is used to inform neighbors that the first subinterface is in normal condition. This is not limited to the first PE.<ESI,EVI> If all network elements within the scope execute step S101, then each network element will be able to learn the [resource / information].<ESI,EVI> This information includes the node information of all normally functioning sub-interfaces within the scope, thereby excluding nodes containing normally functioning sub-interfaces.<ESI,EVI> Outside of the DF election process.

[0090] It should be noted that the first sub-interface and the second sub-interface belong to the same...<ESI,EVI> Furthermore, the first route announcement message and the first route cancellation message are also targeted at...<ESI,EVI> Specifically, in this embodiment, the focus is on <first ESI, first EVI>, and therefore they can be connected via...<ESI,EVI> Information is cross-indexed.

[0091] In another implementation, to conserve network resources, step S101 is unnecessary. Instead, each network element is assumed to have already learned the routing information from all nodes except the one that sent the first routing advertisement message.<ESI,EVI> The corresponding sub-interfaces are valid on all other nodes, thus excluding nodes whose corresponding sub-interfaces are invalid.<ESI,EVI> Outside of the DF election process.

[0092] It should be noted that, in one embodiment, excluding a node from the DF election process means excluding the Ethernet segmented routes sent by that node from the corresponding...<ESI,EVI> Outside of the DF election process.

[0093] In some embodiments, such as Figure 3 As shown, in response to receiving the first route advertisement message published by the second PE, the following steps are also included:

[0094] S102: In response to receiving the Ethernet segmented route carrying the first indication information published by the second PE, each segmented route in the first ES will be...<ESI,EVI> The DF election mode is set to the second mode.

[0095] The first indication information is the indication information published when the PE is able to publish and receive the first route.

[0096] It should be noted that, through the first indication information, a node implementing the present invention can confirm whether there are any nodes in the network that have not implemented the present invention. Only when all PEs on the same ES have implemented the present invention will the node implementing the present invention truly publish the first route advertisement message. When the first PE receives an Ethernet segmented route carrying the first indication information published by the second PE, it will also determine whether it has received the first route and will then distribute the first route advertisement message to all PEs on the first ES that have not received the first route advertisement message.<ESI,EVI> The DF election is set to the second mode, and all routes that have received the first route advertisement message are included.<ESI,EVI> The DF election is set to the first mode.

[0097] In some embodiments, such as Figure 4 As shown, in response to receiving the first route advertisement message published by the second PE, the following steps are also included:

[0098] S103: In response to receiving the first route advertisement message published by the second PE, the DF election mode is switched to the first mode only when all the Ethernet segment routes of the first ES carry the first indication information.

[0099] Because each<ESI,EVI> The initial DF election mode is mode two, so there is no need to publish Ethernet auto-discovery routes based on EVI. However, when a certain<ESI,EVI> When a sub-interface fault does indeed exist, this<ESI,EVI> The DF election mode on the device was then switched to the first mode. At this time, the...<ESI,EVI> Only then do we need to advertise routes of comparable magnitude to those in EVI-based Ethernet auto-discovery (e.g., the first route), each<ESI,EVI> Each enters the first mode. When<ESI,EVI> When there are no faults, both the first and second modes can produce correct results in DF election. However, the second mode has better performance because it reduces the number of routes that need to be advertised by orders of magnitude.

[0100] In some embodiments, such as Figure 5 As shown, in response to receiving the first route revocation message published by the second PE, the following steps are included:

[0101] S104: In response to receiving the first route withdrawal message published by the second PE, the DF election mode is switched from the first mode to the second mode only if all the received Ethernet segment routes of the first ES carry the first indication information.

[0102] Corresponding to step S103, when the second sub-interface returns to normal, it is also necessary to notify the DF mode on the corresponding ESI to switch to the second mode before step S103 through the first route cancellation message.

[0103] In some embodiments, in response to receiving a first route advertisement message published by the second PE, the Ethernet segmented route published by the second PE for the first ES is excluded from the DF election process corresponding to the first sub-interface. The first route is an EVI-based Ethernet auto-discovery route that additionally carries second indication information, which is carried in the EVPN Layer 2 Attributes Extended Community attribute, specifically in a flag bit in the "Control Flags" field of that attribute; for ease of description, this can be referred to as the AC failure flag bit. When the second interface fails, the second PE publishes an Ethernet auto-discovery route advertisement message in this format, where the value of the AC failure flag bit is set to "1" to inform the receiving PE that it is a first route advertisement message.

[0104] Optionally, the AC flag may not be limited to 1 bit, nor is it limited to setting it to "1" to indicate AC failure. As long as the Control Flags include a setting that indicates the meaning of the AC failure flag, it is within the scope of protection of this invention.

[0105] When the first PE receives the first route advertisement message, it excludes the corresponding Ethernet segment route from the DF election process.

[0106] In some embodiments, before receiving the first route advertisement message, the Route Target Membership NLRI containing the first route target is advertised to the neighbor through the BGP Route Target Constraints mechanism.

[0107] Normally, the EVPN routes of the second PE are not restricted during publication and are sent to all neighbors with the Route Target. The receiving side matches routes based on the Route Target and only accepts routes that can be matched. In this embodiment, the ES range is limited by the Route Target, which can avoid consuming routing resources on unnecessary neighbors.

[0108] Route Targets can be of special types, such as ES Import RT and EVI Route Target (EVI-RT). The purpose is that when the first route advertisement message carries both the first ES Route Target and the first EVI Route Target, the node receiving the first route advertisement message can distinguish between the two types of Route Targets, thereby controlling the import range of the first route to PEs within the same ES. Other unrelated PEs in the network will not accept routes with these Route Targets. Furthermore, routes can only be imported if both the ES Import RT and EVI-RT match.

[0109] On the routing path, there may be nodes running the RT Constraints mechanism (such as a RR node), which will restrict the EVPN routes advertised by the second PE. To avoid the impact of the RT Constraints mechanism, before receiving the first route advertisement message, the Routing Target Membership (NLRI) containing the first route target is advertised to the neighbor through the BGP Route Target Constraints mechanism. This allows the first route carrying the first route target to be forwarded smoothly in the network.

[0110] In some embodiments, such as Figure 6 As shown, the received first route advertisement message contains the route target RouteTarget and includes the following steps:

[0111] S105: The third PE responds to receiving a first route advertisement message published by the second PE with a Route Target that specifies the first ES, and the third PE does not have an ES that matches the route target locally, by filtering the first route advertisement message.

[0112] In this scenario, the second PE and the third PE have an EVPN neighbor relationship, and none of the third PE's sub-interfaces are on the first ES. When the second PE publishes a first route advertisement message that specifies the route target for the first ES, the third PE cannot receive the first route advertisement message because none of its sub-interfaces are on the first ES, and therefore there is no ES matching the route target locally.

[0113] Secondly, embodiments of this disclosure provide an information transmission method for a second PE, such as... Figure 7 As shown, it includes the following steps:

[0114] S300: In response to the failure of the second sub-interface, publishes the first routing advertisement message.

[0115] Both the first sub-interface and the second sub-interface are bound to the first EVI, and both the first sub-interface and the second sub-interface are sub-interfaces on the first ES.

[0116] When the ESI main interface is not faulty but its sub-interface is faulty, neighboring network elements need to be notified, and the corresponding sub-interface should be checked.<ESI,EVI> In the DF election process, the node containing the sub-interface (such as the second sub-interface) (i.e., the node that published the first route advertisement message) is excluded; otherwise...<ESI,EVI> The DF election results are abnormal.

[0117] The first route advertisement message is a route advertisement message carrying MP_REACH_NLRI issued by the second PE in response to the state change of the second subinterface when the second subinterface fails. The first route can be implemented by adding a special flag to an existing route type, by adding a new address family, or by adding a new route type. For example, a new EVPN route type with a route type code greater than 13 can be used.

[0118] Although the first route advertisement message targets a sub-interface "failure," this invention uses the multi-protocol network layer reachability information MP_REACH_NLRI, not the multi-protocol network layer unreachability information MP_UNREACH_NLRI. The reason is that MP_REACH_NLRI is for route advertisements, while MP_UNREACH_NLRI is for the revocation of MP_REACH_NLRI. If no MP_REACH_NLRI corresponding to MP_UNREACH_NLRI has been received before, then a route revocation message carrying MP_UNREACH_NLRI is naturally invalid. The usual practice is to discard route revocation messages carrying this MP_UNREACH_NLRI.

[0119] For example, when the second PE and the first PE need to forward routing messages through the route reflector (RR), suppose the second PE uses a route revocation message carrying MP_UNREACH_NLRI to announce the failure of the second sub-interface. The RR has never received the MP_REACH_NLRI corresponding to that MP_UNREACH_NLRI, so when the RR receives the route revocation message carrying that MP_UNREACH_NLRI, it will discard the message and will not forward it to the first PE.

[0120] In this invention, the first route simply announces the "failure" of the sub-interface to its neighbors as part of the routing message. The "failure" of the sub-interface is not the same as the "reachability" of MP_REACH_NLRI. Taking the RR scenario mentioned above as an example, when the second sub-interface fails, the second PE announces the failure of the second sub-interface using a routing announcement message carrying MP_REACH_NLRI. After receiving the routing announcement message, the RR will forward it to the first PE.

[0121] S400: In response to the second sub-interface returning to normal, publishes a first route cancellation message.

[0122] When the second subinterface recovers, the first PE in this invention uses a route cancellation message carrying MP_UNREACH_NLRI to cancel the corresponding route advertisement message carrying MP_REACH_NLRI published when the subinterface "failed" in step S300. Taking the RR scenario in step S300 as an example, when the second subinterface recovers, the second PE publishes a route cancellation message carrying MP_UNREACH_NLRI to cancel the previously published corresponding route advertisement message carrying MP_REACH_NLRI. After receiving the route cancellation message carrying MP_UNREACH_NLRI, the RR finds that it has previously received the corresponding route advertisement message carrying MP_REACH_NLRI, so it will not discard it directly, but will forward this message to the first PE.

[0123] In some embodiments, such as Figure 8 As shown, in response to the failure of the second sub-interface, the following steps are also included:

[0124] S301: Before publishing the first route advertisement message, the published Ethernet segment route carries the first indication information.

[0125] The first indication information is the indication information that is only published when the PE is able to publish and receive the first route.

[0126] This embodiment further extends the DF Election extended community attribute by adding a flag bit to the "Bitmap" field indicating a switch to AC-DF mode based on EVI (referred to as AC-DF per EVI, an implementation of the first indication information). This indicates that the second PE has implemented the invention (i.e., it can send and receive the first route). In this case, the second PE is said to be performing EVI-based AC-DF mode on the first ES. The so-called EVI-based AC-DF mode refers to the initial state (i.e., a state without any faults) on each ES.<ESI,EVI> Both adopt the second mode, and when a certain is perceived<ESI,EVI> After the failure, then separately at this<ESI,EVI> Enabling the first mode at the granular level, when the<ESI,EVI> After the fault is resolved, it will revert to the second mode.

[0127] It should be noted that the AC-DF mode based on EVI refers to the various...<ESI,EVI> The overall situation of the DF election mode (i.e., mode one or mode two), while mode one and mode two refer to a specific one of the ES.<ESI,EVI> The DF election mode. In this sense, the first indication information also indicates the respective ESIs.<ESI,EVI> The overall DF election mode adopted is an AC-DF mode based on EVI. The first indication information indicates that the second PE has implemented the present invention, or that the first indication information indicates that the second PE can send and receive the first route, or that the first indication information indicates that the second PE is a member of the first ES.<ESI,EVI> The overall situation of the DF election mode adopted is the AC-DF mode based on EVI, which is a different expression of the same meaning.

[0128] It should be noted that, further, when all Ethernet segment routes carry the first indication information, it indicates that each PE node on the corresponding ES has implemented this invention. At this point, it can be said that the negotiation at the ES level supports the first route, or it can be said that the DF election mode is negotiated at the ES granularity as an AC-DF mode based on EVI, or it can be said that each PE node on the ES...<ESI,EVI> The overall negotiation of the adopted DF election mode is based on the AC-DF mode based on EVI. These statements are all different ways of expressing the same meaning.

[0129] In some embodiments, the first indication information is further set simultaneously with the AC-DF capability flag.

[0130] In the Bitmap field of the extended community attribute, the first indication information in the DF election mode flag and the AC-DF Capability flag can be set simultaneously.

[0131] When the first indication information and the AC-DF capability flag in the Bitmap field are both set, if all Ethernet segment routes in the ESI carry the first indication information (indicating that there are no nodes in the ES that have not implemented this invention), the AC-DF capability flag automatically becomes invalid; otherwise, the AC-DF capability flag remains valid. This ensures that even when there are nodes in the ES that do not support the first indication information, the DF can still be elected according to the method indicated by the AC-DF flag, thereby better leveraging the DF election capabilities of nodes that support AC-DF but have not implemented this invention.

[0132] In some embodiments, such as Figure 9 As shown, in response to the failure of the second sub-interface, the following steps are included:

[0133] S302: In response to the failure of the second sub-interface, the first route advertisement message is published to the neighbor only if the first indication information is carried in the Ethernet segmented routes published by all PEs.

[0134] The first indication information is the indication information published when the PE is able to publish and receive the first route.

[0135] In this embodiment, the first routing message does not add a new routing type; it still uses the existing EVI-based Ethernet auto-discovery routing message to announce the status change of the second sub-interface to the first PE. The advantage of this approach is that it is easier to be compatible with existing networks (such as RR nodes within them).

[0136] It should be noted that, through the first indication information, a node implementing the present invention can confirm whether there are nodes in the network that have not implemented the present invention. Only when all PEs on the same ES have implemented the present invention will the node implementing the present invention actually publish the first routing advertisement message. In this way, when there are nodes in the network that have not implemented the present invention (i.e., have not carried the first indication information in the Ethernet segmented route), they are processed according to the rules when all Ethernet segmented routes of the corresponding ESI have not carried the first indication information, thereby ensuring that the present invention will not worsen the result when new and old nodes are mixed in the network.

[0137] Furthermore, such as Figure 10 As shown, in response to the failure of the second sub-interface, the following steps are also included:

[0138] S303: In response to the failure of the second sub-interface, in the first routing advertisement message, the MPLS Label field is set to a reserved value, and the Ethernet TagID field of the first routing advertisement message is set to the I-Component Service Identifier (I-SID) value corresponding to the first EVI. The routing target of the first backbone component (B-Component) is carried in the first routing advertisement message, wherein the first backbone component is the backbone component bound to the first EVI.

[0139] Based on step S301, in order to distinguish it from the regular settings in MP_REACH_NLRI, special settings are made for MP_REACH_NLRI in EVI-based Ethernet automatic discovery routing. These settings include setting the MPLS Label field to a reserved value that does not conflict with existing protocols, such as 0, and setting the Ethernet Tag ID field to the I-SID value corresponding to the first EVI.

[0140] In some embodiments, in response to the failure of the second sub-interface, the published first routing advertisement message carries second indication information.

[0141] The second indication information is used to identify the route as the first route.

[0142] In this embodiment, the first route can be a newly added route type (in this case, the value of the route type is the second indication information), or it can be a special setting on the EVI-based Ethernet auto-discovery route.

[0143] In one embodiment, the first route uses the L2VPN / EVPN address family with an NLRI type of 1. An AC failure flag is added to the Control Flags field of the extended community attribute of the EVPN Layer 2 attribute. This AC failure flag is the second indication information. The receiving side can determine that the second sub-interface of the second PE has failed based on the AC failure flag in the extended community attribute, and can also identify that the Ethernet segmented route advertised by the second PE for the first ES is excluded from the DF election process corresponding to the first sub-interface.

[0144] In some embodiments, such as Figure 11 As shown, in response to the failure of the second sub-interface, the following steps are also included:

[0145] S304: In response to the failure of the second sub-interface, the first route target corresponding to the first ES is carried in the published first route advertisement message.

[0146] Normally, the EVPN routes of the second PE are not restricted during publication and are sent to all neighbors with a Route Target. The receiving side matches routes based on the Route Target and only accepts routes that can be matched. Limiting the ES range through the Route Target can avoid consuming routing resources on unnecessary neighbors.

[0147] In this embodiment, the first route can be a newly added route type, or it can be a route with special settings based on EVI-based Ethernet auto-discovery. The MP_REACH_NLRI field is filled in the same way as EVI-based Ethernet auto-discovery, but its Route Target uses a special type, such as ES Import RT or EVI-RT. The purpose is that when the first route advertisement message carries both the Route Target of the first ES and the Route Target of the first EVI, the node receiving the first route advertisement message can distinguish between the two Route Targets, thereby controlling the import range of the first route to PEs within the same ES. Other unrelated PEs in the network will not accept routes with these Route Targets. In this case, the appearance of ES Import RT and / or is the second indication information.

[0148] In some embodiments, the first routing target constraint mechanism on the routing target (RT Constraints) is visible.

[0149] On the routing forwarding path, the RT Constraints mechanism may be running, which will restrict the EVPN routes advertised by the second PE. To avoid the impact of the RT Constraints mechanism, before receiving the first route advertisement message, the NLRI (Neighborhood Reference Information) for the route target constraint is advertised to the neighbor through the BGP route target constraint RT Constraints mechanism. The first route target is visible to the route target constraint RT Constraints mechanism, meaning that the RT Constraints mechanism will check the first route target. If the first route target does not match the route target membership, the route with the first route target will not be advertised.

[0150] In some embodiments, the first route target is used to allow PE nodes not on the first ES to filter the first route advertisement message.

[0151] The first route advertisement message carries both the Route Target of the first Elastic Element (ES) and the Route Target of the first EVI. Since the PE node is not in the first ES, the Route Target of the first ES cannot be matched, and the third PE will not process the first route advertisement message.

[0152] In some embodiments, such as Figure 12 As shown, in response to the failure of the second sub-interface, the following steps are also included:

[0153] S305: In response to the failure of the second subinterface, the first route advertisement message is carried with the second route target corresponding to the first EVI, and the second route target is not visible to the RT Constraints mechanism.

[0154] By setting the second route target corresponding to the first EVI to be invisible to the RT Constraints mechanism, even if the third PE indicates through the RT Constraints mechanism that it wants to receive routes carrying this route target, the first route advertisement message will not be forwarded to the third PE because it does not match the route target corresponding to the first ES. This ensures that in a network where RT Constraints are deployed, the first route advertisement message will only reach the PE node on the first ES. For example, since the third PE is configured with the first EVI, it will publish the Route Target Membership NLRI for the route target of the first EVI (i.e., the second route target), but will not publish the Route Target Membership NLRI for the route target of the first ES (i.e., the first route target). Therefore, although the first route advertisement message contains the second route target, because this route target is invisible to the RT-Constraints mechanism, the first route advertisement message will not be published to the third PE because the first route target does not match the Route Target Membership NLRI published by the third PE.

[0155] This invention provides a specific example, such as Figure 13 As shown, PE1 and PE2 are the first PE and the second PE, respectively (it is not limited to PE1 being the first PE and PE2 being the second PE; the specific role correspondence depends on the actual situation). PE3 is an example of other PE devices (such as the third PE). R4 and R5 are example of other devices between PEs. The ESI of the ES where the CE is located is ESI2. ESI2 is bound to the main interface IF_1, but the service is bound to the sub-interfaces IF_1.1 and IF_1.2 of IF1. The sub-interfaces IF_1.1 and IF_1.2 are bound to the I component as ACs. The first route is published in the I component, but Ethernet auto-discovery routes are not published.

[0156] In this context, the I-component is the I-component of PBB EVPN. Besides the I-component, PBB EVPN also has a B-component. In this embodiment, there are two EVPN instances named 100 and 200. Each EVPN instance has a corresponding I-component on each PE. DF election is conducted for each...<ESI,EVI> Select a unique DF node. For example, for<ESI2,EVI100> The DF election results are: PE1 is DF, PE2 is not DF; and for<ESI2,EVI200> The election results for DF are: PE1 is not DF and PE2 is DF.

[0157] By default, the main interface IF_1 and all its sub-interfaces on each PE of ESI2 are UP. Therefore, the DF election of ESI2 adopts the second mode. That is to say, the current DF election result is not affected by the existence of EVI-based Ethernet auto-discovery routes, which do not contain the second indication information.

[0158] When sub-interface IF_1.1 on PE1 fails while its main interface and other sub-interfaces remain functional, PE1 advertises a first route for sub-interface IF_1.1. Other PEs on the same Elasticsearch Entity (PEn, for example) can then use this first route to route the corresponding...<ESI,EVI> The DF election on the platform switched from the second mode to the first mode.

[0159] When sub-interface IF_1.1 on PE1 recovers, PE1 publishes the cancellation of the first route. When PEN receives this cancellation notification, it cancels the first route previously received from PE1 and then...<ESI,EVI> The DF election on the platform switches from mode one to mode two if the same<ESI,EVI> If no other first route exists, then all Ethernet segment routes published by PE for this ESI will participate in the targeting of this ESI.<ESI,EVI> The DF election process.

[0160] Besides PBB EVPN, this invention is also applicable to scenarios involving Virtual Extensible Local Area Network (VXLAN) EVPN or Segment Route IPv6 (SRv6) EVPN where Ethernet routes are not advertised for automatic discovery. In these scenarios, instead of using MAC / IP address advertising routes, the function of remote MAC entries can be replaced by learning them on the data plane.

[0161] It should be noted that in the PBB EVPN scenario, the first route advertisement message may only carry the RouteTarget of the B component and not the RouteTarget of the I component. In this case, the first route advertisement messages for different I components can be distinguished by setting the EthernetTag ID field in the first route advertisement message to the corresponding I-SID.

[0162] It's worth noting that the first route can be a new EVPN route type (when the second indication information is its route type). As mentioned above, its timing for advertising and revoking Ethernet auto-discovery routes is the opposite; that is, the latter's advertising timing is its revocation timing, and vice versa. Therefore, the first route is advertised during a fault and revoked when the fault is recovered. Since faults are isolated, the first route is not normally advertised, meaning it doesn't consume network resources under normal circumstances. Only when a certain fault occurs...<ESI,EVI> When a sub-interface failure actually exists, the DF election switches to the first mode. Only then does it need to advertise routes of a scale equivalent to the number of failed sub-interfaces, instead of routes of a scale equivalent to the number of unfailed sub-interfaces. Since the number of failed sub-interfaces is far less than the number of unfailed sub-interfaces, the number of routes that need to be advertised in the first mode is reduced by orders of magnitude. In the second mode, it is not necessary to advertise routes of a scale equivalent to the number of sub-interfaces, thus reducing system overhead and saving network resources.

[0163] Thirdly, such as Figure 14 As shown, the present invention provides a PE device, which includes:

[0164] One or more processors 501;

[0165] Memory 502, having stored one or more programs, which, when executed by one or more processors, cause the one or more processors to implement the method of the first or second aspect of any of the above.

[0166] One or more I / O interfaces 503 are connected between the processor and the memory and configured to enable information exchange between the processor and the memory.

[0167] Among them, processor 501 is a device with data processing capabilities, including but not limited to central processing unit (CPU); memory 502 is a device with data storage capabilities, including but not limited to random access memory (RAM, more specifically SDRAM, DDR, etc.), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory (FLASH); I / O interface (read-write interface) 503 is connected between processor 501 and memory 502, and can realize information interaction between processor 501 and memory 502, including but not limited to data bus (Bus).

[0168] In some embodiments, the processor 501, memory 502, and I / O interface 503 are interconnected via bus 504, and thus connected to other components of the computing device.

[0169] Fourthly, such as Figure 15 As shown, the present invention provides a computer-readable medium having a computer program stored thereon, which, when executed by a processor, implements any of the methods of the first or second aspect described above.

[0170] It will be understood by those skilled in the art that all or some of the steps, systems, or apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0171] Exemplary embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in connection with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A method for switching a designated forwarder (DF) election mode, used in a first provider network edge (PE), wherein both the first PE and a second PE are on a first Ethernet segment (ES), the first PE has a first sub-interface, and the second PE has a second sub-interface corresponding to the first sub-interface, both the first and second sub-interfaces are bound to a first Ethernet Virtual Private Network (EVI), and both the first and second sub-interfaces are sub-interfaces on the first ES; wherein, The method includes: In response to receiving the first route advertisement message published by the second PE, the DF election mode corresponding to the first sub-interface is switched to the first mode, which is the DF election mode in which no Ethernet segmented route published by the second PE for the first ES participates; In response to receiving the first route withdrawal message published by the second PE, the DF election mode is switched from the first mode to the second mode, the second mode being the DF election mode in which the Ethernet segmented routes published by the second PE for the first ES are involved; Wherein, the first route is the route advertised by the second PE in response to the change in the state of the second sub-interface; the first route advertisement message is a route advertisement message carrying multi-protocol network layer reachability information MP_REACH_NLRI advertised by the second PE in response to the change in the state of the second sub-interface when the second sub-interface fails; the first route cancellation message is a route cancellation message carrying multi-protocol network layer unreachability information MP_UNREACH_NLRI advertised by the second PE in response to the change in the state of the second sub-interface when the second sub-interface recovers.

2. The method according to claim 1, wherein, Also includes: In response to receiving the first route advertisement message published by the second PE and the first sub-interface being in normal status, a route advertisement message indicating that the first sub-interface is in normal status is published for the first sub-interface.

3. The method according to claim 1, wherein, Prior to receiving the first route advertisement message published by the second PE, the method further includes: In response to receiving the Ethernet segmented route carrying the first indication information published by the second PE, each of the first ES is...<ESI,EVI> The DF election mode on the screen is set to the second mode; The first indication information is the indication information published when the PE is able to publish and receive the first route.

4. The method according to claim 1, wherein, The step of switching the DF election mode corresponding to the first sub-interface to the first mode in response to receiving the first route advertisement message from the second PE includes: in response to receiving the first route advertisement message published by the second PE, switching the DF election mode to the first mode only when all the Ethernet segment routes of the first ES received carry the first indication information; The step of switching the DF election mode from the first mode to the second mode in response to receiving the first route revocation message from the second PE includes: in response to receiving the first route revocation message published by the second PE, switching the DF election mode from the first mode to the second mode only when all the Ethernet segment routes of the first ES received carry the first indication information; The first indication information is the indication information published when the PE is able to publish and receive the first route.

5. The method according to any one of claims 1 to 4, wherein, The second PE also has an EVPN neighbor relationship with the third PE, and none of the sub-interfaces of the third PE are on the first ES; the method further includes: The third PE, in response to receiving a first route advertisement message from the second PE containing a route target RouteTarget that defines a first ES, and the third PE not having an ES matching the route target locally, filters the first route advertisement message.

6. A method for transmitting information, used in a second provider network edge (PE), wherein both the second PE and a first PE are on a first Ethernet segment (ES), the first PE is configured with a first sub-interface, the second PE is configured with a second sub-interface corresponding to the first sub-interface, both the first and second sub-interfaces are bound to a first Ethernet Virtual Private Network (EVI), and both the first and second sub-interfaces are sub-interfaces on the first ES; wherein, The method includes: In response to the failure of the second sub-interface, a first routing announcement message is published; In response to the second sub-interface returning to normal, a first route cancellation message is published; Wherein, the first route is the route advertised by the second PE in response to the change in the state of the second sub-interface; the first route advertisement message is a route advertisement message carrying multi-protocol network layer reachability information MP_REACH_NLRI advertised by the second PE in response to the change in the state of the second sub-interface when the second sub-interface fails; the first route cancellation message is a route cancellation message carrying multi-protocol network layer unreachability information MP_UNREACH_NLRI advertised by the second PE in response to the change in the state of the second sub-interface when the second sub-interface recovers.

7. The method according to claim 6, wherein, Also includes: Before publishing the first route advertisement message, the published Ethernet segmented route carries the first indication information; The first indication information is the indication information published when the PE is able to publish and receive the first route.

8. The method according to claim 6, wherein, The response to the failure of the second sub-interface, including publishing a first routing announcement message, includes: In response to the failure of the second sub-interface, the first route advertisement message is only published to the neighbor if all Ethernet segment routes published by the PE carry the first indication information; The first indication information is the indication information published when the PE is able to publish and receive the first route.

9. The method according to claim 8, wherein, Also includes: In response to the failure of the second sub-interface, the Multiprotocol Label Switching Protocol Label (MPLS Label) field in the first routing advertisement message is set to a reserved value, and the Ethernet TagID field in the first routing advertisement message is set to the I-Component Service Identifier (I-SID) value corresponding to the first EVI. The routing target of the first backbone component (B-Component) is carried in the first routing advertisement message, wherein the first backbone component is the backbone component bound to the first EVI.

10. The method according to any one of claims 6 to 9, wherein, Also includes: In response to the failure of the second sub-interface, the first route advertisement message published carries the first route target corresponding to the first ES.

11. The method of claim 10, wherein: The first routing target's constraint mechanism on the routing target (RT Constraints) is visible; or, The first route target is used to allow PEs not on the first ES to filter the first route advertisement message.

12. The method according to any one of claims 6 to 9, wherein, Also includes: In response to the failure of the second sub-interface, the first route advertisement message published carries the second route target corresponding to the first EVI, and the second route target is not visible to the route target constraint RT Constraints mechanism.

13. A provider network edge PE device, comprising: One or more processors; A memory having stored one or more programs thereon, which, when executed by the one or more processors, cause the one or more processors to implement the method according to any one of claims 1 to 12; One or more I / O interfaces are connected between the processor and the memory and configured to enable information interaction between the processor and the memory.

14. A computer-readable medium having a computer program stored thereon, which, when executed by a processor, implements the method according to any one of claims 1 to 12.

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