CN111865786B

CN111865786B - Method and apparatus for propagating link markers

Info

Publication number: CN111865786B
Application number: CN202010607562.8A
Authority: CN
Inventors: 林长望; 李�昊; 常露; 陈梦骁
Original assignee: Beijing H3C Technologies Co Ltd
Current assignee: Beijing H3C Technologies Co Ltd
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2022-07-12
Anticipated expiration: 2040-06-30
Also published as: CN111865786A

Abstract

The application provides a method and a device for propagating link marks, wherein the method IS applied to a first router, the first router runs an IS-IS protocol, the first router and a second router are mutually adjacent, and the method comprises the following steps: acquiring a link marking value of a first designated link; and sending a first Link State Protocol Data Unit (LSPDU) to the second router, wherein the first LSPDU comprises the link flag value, so that when the second router starts a route filtering mode, or the second router is a Level-1-2 router, a designated route is determined according to the link flag value, and a transmission path corresponding to the designated route comprises the first designated link.

Description

Method and apparatus for propagating link markers

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method and an apparatus for propagating a link marker.

Background

At present, according to The specification of The existing Intermediate System-Intermediate System (IS-IS) protocol (specifically, RFC-5130), an administitive Tag Sub-TLV can be used to carry a Tag value and IS filled in TLV 135(The Extended IP responsiveness TLV, RFC-3784), TLV235 (Multi-Topology responsiveness IPv4 preferences TLV, RFC-5120), TLV236 (IPv6 responsiveness TLV, RFC-5308) or TLV237 (Multi-Topology responsiveness IPv6 preferences, RFC-5120). The tag value is specified by the router that generated the route, and the aforementioned TLVs are all used to describe prefix routes.

As shown in fig. 1, G, E IS a border router of the backbone network, a IS an access router of the subnet 1, and the backbone network runs the IS-IS protocol. In the networking, the backbone network needs to filter the route issued by a on the subnet 1, but the backbone network cannot effectively manage a, and only the routers (including G, E) included in the backbone network can be configured and managed.

At this time, the route issued by a on the subnet 1 does not carry a route label, and the router included in the backbone network cannot add a route label to the route of the subnet 1, so the router in the backbone network cannot distinguish the route of the subnet 1 issued by a, and cannot perform network control actions such as filtering and routing policy on the path of the subnet 1.

Disclosure of Invention

In view of this, the present application provides a method and an apparatus for propagating a link label, so as to propagate a link label value of a certain link (or several links) in an IS-IS network, so that other routers in the network identify a route propagated through the link(s), thereby implementing network control behaviors such as route filtering, route policy, and the like.

In a first aspect, the present application provides a method for propagating a link label, where the method IS applied to a first router, where the first router runs an IS-IS protocol, and the first router and a second router are neighbors of each other, and the method includes:

acquiring a link marking value of a first designated link;

and sending a first Link State Protocol Data Unit (LSPDU) to the second router, wherein the first LSPDU comprises the link mark value, so that when the second router starts a route filtering mode, or the second router is a Level-1-2 router, a designated route is determined according to the link mark value, and a transmission path corresponding to the designated route comprises the first designated link.

In a second aspect, the present application provides a device for propagating a link label, where the device IS applied to a first router, the first router runs an IS-IS protocol, and the first router and a second router are neighbors of each other, and the device includes:

an acquisition unit, configured to acquire a link flag value of a first designated link;

a sending unit, configured to send a first link state protocol data unit to the second router, where the first LSPDU includes the link flag value, so that when the second router has started a route filtering mode, or the second router is a Level-1-2 router, a designated route is determined according to the link flag value, and a transmission path corresponding to the designated route includes the first designated link.

In a third aspect, the present application provides a network device comprising a processor and a machine-readable storage medium storing machine-executable instructions executable by the processor, the processor being caused by the machine-executable instructions to perform the method provided by the first aspect of the present application.

Therefore, by applying the method and the device for propagating the link label provided by the present application, after acquiring the link label value of the first designated link, the first router sends the first link state protocol data unit LSPDU to the second router, where the first LSPDU includes the link label value, so that when the second router has started the route filtering mode, or the second router is a Level-1-2 router, the designated route is determined according to the link label value, and a transmission path corresponding to the designated route includes the first designated link. In this manner, the link label value of a certain link (or links) IS propagated in the IS-IS network, so that other routers in the network recognize the route propagated through the link(s), thereby implementing network control actions such as route filtering, route policy, and the like.

Drawings

Fig. 1 is a schematic diagram illustrating a backbone network boundary router filtering an access-side subnet routing scenario provided in the prior art;

fig. 2 is a flowchart of a method for propagating a link label according to an embodiment of the present application;

fig. 3 IS a schematic diagram of a networking of propagation link marker values in an IS-IS network according to an embodiment of the present application;

fig. 4 IS a schematic diagram of a shortest path tree of an IS-IS network according to an embodiment of the present application;

fig. 5 IS a schematic diagram of a shortest path tree of another IS-IS network according to an embodiment of the present application

Fig. 6 IS a schematic diagram of a shortest path tree of yet another IS-IS network according to an embodiment of the present application;

FIG. 7 is a schematic diagram of Link-Tag Sub-TLV fields provided in an embodiment of the present application;

fig. 8 is a diagram illustrating an apparatus for propagating a link marker according to an embodiment of the present disclosure;

fig. 9 is a hardware structure diagram of a network device according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the corresponding listed items.

It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.

The method for propagating link markers provided in the embodiments of the present application is described in detail below. Referring to fig. 2, fig. 2 is a flowchart illustrating a method for propagating a link marker according to an embodiment of the present application. The method is applied to a first router. The first router runs the IS-IS protocol. The first router and the second router are adjacent to each other. The method for propagating the link mark provided by the embodiment of the application can comprise the following steps.

Step 210, a link label value of the first designated link is obtained.

Specifically, as shown in fig. 3, a networking diagram for propagating a link flag value in an IS-IS network according to an embodiment of the present application. The IS-IS network comprises three areas, namely an area 1, an area 2 and an area 3, wherein the area 1 and the area 3 are Level-1 areas, and the area 2 IS a Level-2 area. The node A, the node G, the node C, the node F and the node M are positioned in the area 1; the node E, the node K and the node F are in the area 2; the nodes E and N are located in the area 3. The node A, the node G, the node C, the node M and the node N are Level-1 routers; the node F and the node E are Level-1-2 routers, and the node K is a Level-2 router. The node A and the node M are also configured with IPv4 address prefixes and IPv6 address prefixes.

In the embodiment of the present application, the first router may serve as any one of the nodes.

The specific process of acquiring the link marker value of the first designated link includes the following multiple conditions:

the first condition is as follows: the first router receives a link configuration instruction input by a user, wherein the link configuration instruction comprises an interface identification and a link marking value. For example, the link configuration instructions may be embodied in the "isis link-tag tag" format. According to the interface identification, the first router determines a first designated link connected with the interface indicated by the interface identification.

The tag represents a specific numerical value of the link flag value, and the value range of the tag can be determined according to an application scenario. For example, integers in the range of 1 to 4294967295 may be defined. In the embodiment of the application, the length occupied by the link tag value in the message does not exceed 32 bits.

As shown in fig. 3, the first router is node G. At this time, the user inputs a link configuration instruction under the interface view displayed by the node G. The interface identifier represents an interface included in the node G. A communication link is established with node a through the interface node G. According to the interface identification, the node G determines a first designated link connected with the node A. At the same time, node G marks the first designated link with a link marking value.

Alternatively, the first and second electrodes may be,

in the second case, the first router serves as any node other than the node G, that is, the first router is not a node that directly receives the link configuration instruction input by the user, for example, the node C.

It can be understood that, in the IS-IS network, nodes belonging to the same area and being adjacent to each other issue Link State Protocol Data units (LSPDU or LSP) to each other, and the LSPDU may be specifically Level-1 LSPDU (L1 LSPDU for short) or Level-2 LSPDU (L2 LSPDU for short). For example, node G and node C as Level-1 routers issue L1 LSPDUs to each other in area 1; the node F and the node K serve as Level-2 routers and mutually issue L2LSPDU in the area 2; node E and node N issue L1LSPDU to each other in region 3.

As a Level-1-2 node, LSPDUs in a certain region are distributed to another region. Such as node F. Node F, upon receiving the L1LSPDU issued by node C for zone 1, issues an L2LSPDU to node K, which is within zone 2.

In the embodiment of the present application, each of the L1LSPDU and L2LSPDU includes a first type TLV and a second type TLV. The differences are as follows:

when the Level-1 router issues the L1LSPDU in the Level-1 area, the LSPDU comprises a first type TLV and a second type TLV. The first type TLV carries a link topology attribute and a link mark value in a Level-1 area; the second type TLV may not fill in specific content, but when the content needs to be filled according to the existing protocol, the protocol specified content is filled;

when the Level-2 router issues the L2LSPDU in the Level-2 area, the LSPDU comprises a first type TLV and a second type TLV. The first type TLV carries a link topology attribute and a link label value; the second type TLV may not fill in specific content, but when the content needs to be filled according to the existing protocol, the protocol specified content is filled;

when a Level-1-2 router issues an LSPDU across areas, if the Level-1-2 router issues an address prefix and a route of a router in a Level-1 area to a router in the Level-2 area, the Level-1-2 router issues an L2 LSPDU. The LSPDU comprises a first type TLV and a second type TLV. The first type TLVs may not be populated with specific content, but are populated with protocol-specified content when the content is required to be populated in accordance with existing protocol specifications; the second type TLV carries an address prefix attribute in a Level-1 area and a link label value;

when a Level-1-2 router issues an LSPDU across areas, if the Level-1-2 router issues address prefixes and routes of other Level-1 areas and routers in the Level-2 area to routers in the Level-1 area, the Level-1-2 router issues an L1 LSPDU. The LSPDU comprises a first type TLV and a second type TLV. The first type TLVs may not fill in specific content, but fill in protocol-specified content when content is specified to be filled according to an existing protocol; the second type TLV carries other Level-1 regions, address prefix attributes within Level-2 regions, and link label values.

In summary, LSPDUs are of different types according to different roles of the nodes.

In this case, the first router receives a second LSPDU sent by a third router which is adjacent to the first router, where the second LSPDU includes a first type TLV, and the first type TLV includes a link topology attribute and a link label value. The first router determines a first designated link based on the link topology attributes.

As shown in fig. 3, the first router is node C. Node C receives the L1LSPDU issued by node G, wherein the L1LSPDU comprises a first type TLV comprising a link topology attribute and a link label value. And if the node C starts a route filtering mode, the node C determines that the first appointed link is a link between the node G and the node A according to the link topology attribute. At the same time, node C marks the first designated link with a link marking value.

As shown in fig. 3, the first router is node F. Node F receives the L1LSPDU issued by node C, wherein the L1LSPDU comprises a first type TLV comprising a link topology attribute and a link label value. According to the link topology attributes, the node F determines that the first designated link is a link between the node G and the node A. At the same time, node F tags the first designated link with a link tag value.

As shown in fig. 3, the first router is node K. Node K receives the L2LSPDU issued by node F, wherein the L2LSPDU includes a second type TLV that also includes a link label value. It is to be understood that this second type TLV also includes an address attribute specifying an address prefix. If node K turns on the route filtering mode, node K marks the route to the specified address prefix with the link label value.

As shown in fig. 3, the first router is node N. Node N receives the L1LSPDU issued by node E, wherein the L1LSPDU comprises a second type TLV that includes a link marker value. It is to be understood that this second-type TLV also includes an address attribute specifying an address prefix. If node N turns on the route filtering mode, node N marks the route to the specified address prefix with a link marker value.

It should be noted that, if the node has started the route filtering mode, or the node is a Level-1-2 router, the node resolves the specified route via the specified link before marking the route with the link marking value, and then marks the specified route with the link marking value, where the specific resolving process is described later.

If the node does not start the route filtering mode, or if the node is a non-Level-1-2 router, the node directly executes step 220 after receiving the second LSPDU, and does not execute the process of distinguishing the designated route.

Step 220, sending a first link state protocol data unit, LSPDU, to the second router, where the first LSPDU includes the link flag value, so that when the second router has started a route filtering mode, or the second router is a Level-1-2 router, a designated route is determined according to the link flag value, and a transmission path corresponding to the designated route includes the first designated link.

Specifically, after acquiring the link flag value of the first designated link, the first router generates a first LSPDU. The first LSPDU includes a link marker value. The first router sends a first LSPDU to the second router. And after receiving the first LSPDU, the second router acquires a link label value from the first LSPDU. And determining a designated route according to the link marking value, wherein a transmission path corresponding to the designated route comprises the first designated link.

Further, the first router generates and sends the first LSPDU to the second router in different ways according to the difference of its own role, and the specific process includes the following situations:

the first condition is as follows: the first router acquires the link label value in a mode of receiving a link configuration instruction input by a user, and generates and sends a first LSPDU to a second router. Wherein the first LSPDU includes a first type TLV. The first type TLVs include a link topology attribute and a link label value.

As shown in fig. 3, the first router is node G. According to the description of step 210, the node G obtains the link flag value according to the link configuration instruction input by the user. Meanwhile, according to the interface identifier, the node G determines that the link connected with the node A is a first designated link. Node G marks the first designated link with a link marking value. The node G generates a first LSPDU, wherein the first LSPDU comprises a first type TLV comprising a link topology attribute and a link label value. Node G sends the first LSPDU to node C.

As shown in fig. 3, the first router is node F. And the node F acquires a link mark value according to a link configuration instruction input by a user. Meanwhile, according to the interface identifier, the node F determines that the link connected with the node M is the first designated link. Node F marks the first designated link with a link label value. The node F, as a Level-1-2 router, needs to transmit information such as addresses and routes in the area 1 to nodes included in the area 2, and generates a first LSPDU, where the first LSPDU includes a second type TLV that includes a link flag value (link flag value of link F-M). Node F sends the first LSPDU to node K.

It will be appreciated that node F also performs a process similar to node G generating a first LSPDU comprising a first type TLV comprising link topology attributes and a link label value (link label value for link F-M). Node F sends the first LSPDU to node C.

Case two: when the first router is a Level-1-2 router or the first router opens a route filtering mode, the first router judges whether a specified address prefix is recorded locally or not, and the specified address prefix arrives through a first specified link. If the local record specifies an address prefix, the first router generates a first LSPDU and sends the first LSPDU to the second router.

Wherein the first LSPDU comprises a first type TLV, or the first LSPDU comprises a second type TLV. The first type TLV includes a link topology attribute and a link label value; the second type TLV includes an address attribute specifying an address prefix and a link tag value.

As shown in fig. 3, the first router is node F. A subnet is accessed at node a. The subnet comprises two address prefixes, one is that the address prefix of IPv6 is 1: 1:/64, and the other is that the address prefix of IPv4 is 1.1.1.0/24.

Node F receives the L1LSPDU issued by node C, wherein the L1LSPDU includes a first type TLV that includes a link topology attribute and a link label value, as depicted in step 210. According to the link topology attributes, the node F determines that the first designated link is a link between the node G and the node A. At the same time, node F marks the first designated link with a link marker value.

Because the node F is located at the boundary between two areas, the node F, as a Level-1-2 router, needs to transmit information such as addresses and routes in the area 1 to the nodes included in the area 2. At this time, the node F judges whether a specified address prefix (e.g., IPv6 address prefixes 1: 1:/64, IPv4 address prefixes 1.1.1.0/24) is locally recorded, the specified address prefix being reached via the G-A link.

If node F records a specified address prefix locally, node F generates an L2LSPDU, wherein the L2LSPDU includes a second type TLV that includes an address attribute specifying the address prefix and a link label value. Node F sends an L2LSPDU to node K.

Further, the specific process of the node F determining whether to record the specified address prefix locally is as follows:

through the shortest path tree algorithm, when the node F calculates the route, the node F is used as a root node to establish a shortest path tree, and the shortest path tree also comprises a plurality of child nodes. From the shortest path tree, node F determines whether there is a child node with a link flag value. If so, node F determines if the child node has the specified address prefix (e.g., IPv6 address prefix 1: 1:/64, IPv4 address prefix 1.1.1.0/24). If the child node has a specified address prefix, node F marks the route to the specified address prefix as a link label value.

As shown in fig. 4, fig. 4 IS a schematic diagram of a shortest path tree of an IS-IS network according to an embodiment of the present disclosure; in fig. 4, a node F is a root node, the other nodes are child nodes, and the connection lines between the nodes represent links between the routers. As can be seen from the foregoing, the G-A link is the first designated link, the link label value is 100, and the node F labels 100 the routes to reach the IPv6 address prefixes 1: 1:/64 and IPv4 address prefixes 1.1.1.0/24.

Similarly, if the node C has turned on the route filtering mode, the node C also performs the aforementioned process of the node F resolving the designated route.

Case three: when the first router is a Level-1-2 router or the first router opens a route filtering mode, the first router judges whether a specified address prefix is recorded locally or not, and the specified address prefix arrives through a third router. If the local record specifies an address prefix, the first router generates a first LSPDU and sends the first LSPDU to the second router.

Wherein the first LSPDU comprises a second type TLV. The second type TLV includes an address attribute specifying an address prefix and a link tag value.

As shown in fig. 3, the first router is node E. A subnet is accessed at node a. The subnet comprises two address prefixes, one is that the address prefix of IPv6 is 1: 1:/64, and the other is that the address prefix of IPv4 is 1.1.1.0/24.

Node E receives the L2LSPDU issued by node F forwarded by node K, as depicted in step 210. Wherein the L2LSPDU includes a second type TLV that includes an address attribute specifying an address prefix and a link label value.

Because the node E is located at the boundary of the two regions, the node E, as a Level-1-2 router, needs to transmit the acquired information such as the address and the route in the region 1 to the node included in the region 3. At this time, the node E judges whether or not a specified address prefix (e.g., IPv6 address prefix 1: 1:/64, IPv4 address prefix 1.1.1.0/24) is locally recorded, the specified address prefix being reached via the node F.

If the node E local record specifies an address prefix, then the node E generates an L1LSPDU, wherein the L1LSPDU includes a second type TLV that includes an address attribute specifying the address prefix and a link label value. Node E sends an L1LSPDU to node N.

Further, the specific process of the node E determining whether to locally record the specified address prefix is as follows:

through the shortest path tree algorithm, when the node E calculates the route, the node E establishes a shortest path tree by taking the node E as a root node, and the shortest path tree also comprises a plurality of child nodes. From the shortest path tree, node E determines whether there is a first child node with a link label value that characterizes a third router that sends LSPDUs that include a second type TLVs. If so, node E determines whether the first child node has a specified address prefix (e.g., IPv6 address prefix 1: 1:/64, IPv4 address prefix 1.1.1.0/24). If the first child node has the specified address prefix, the node E judges whether the path reaching the specified address prefix passes through the first child node. If the path to the specified address prefix is via the first child node, node E marks the route to the specified address prefix as a link label value.

As shown in fig. 5, fig. 5 IS a schematic diagram of a shortest path tree of another IS-IS network provided in this application embodiment; in fig. 5, node E is a root node, and the other nodes are child nodes, and the connection lines between the nodes represent links between the routers. As can be seen from the foregoing, the G-A link is the first designated link, the link label value is 100, and the node E labels 100 the route to the IPv6 address prefix 1: 1:/64, the IPv4 address prefix 1.1.1.0/24 and through the node F.

Similarly, if the node K has started the route filtering mode, the node K also performs the aforementioned process of the node F resolving the designated route.

It should be noted that, as shown in fig. 6, fig. 6 IS a schematic diagram of a shortest path tree of an IS-IS network according to another embodiment of the present application. And when the node P calculates the route, the node P generates a shortest path tree by taking the node P as a root node. Since the label value of the P-R link is 100, the child nodes of the link are R and Y, and therefore, node P labels the route to R, Y using a link label value of 100. (if R and Y have IPv6 address prefixes of the access subnet, then node P marks the route to reach IPv6 address prefixes with Link tag value 100; if R and Y have external routes, then node P marks the external route to reach with Link tag value 100.)

In the path of node P to child node X, the Q-S link and the S-X link have different link label values, namely link label value 200 and link label value 300. Since the S-X link is closest to node X, node P chooses the Link tag value 300 to tag the route to X. In the path from the node P to the child node T, the link carrying the link label value nearest to the ion node T is Q-T. The Q-T link has two or more equivalent links, link label value 400 and link label value 500 respectively. Since Link tag value 400 is less than Link tag value 500, node P chooses Link tag value 400 to tag the route to node T.

It should be noted that, links between nodes have directionality, and one link flag value corresponds to one link, for example, in fig. 6, the link flag value of a P-R link is 100, and the link flag value of an R-P link is 200. When the node P calculates the route, it needs to select a corresponding link label value to label the route according to the direction of the link. For example, when node P calculates a route to Y, the link tag value tag of the P-R link is selected to label the route to Y, and the link tag value tag of the R-P link is not selected.

Case four: and when the first router does not start a route filtering mode or is a non-Level-1-2 router, the first router forwards a first LSPDU (link layer protocol data Unit) sent by a third router to the second router.

As shown in fig. 3, the first router is node C. And the node C receives the L1LSPDU issued by the node G, and if the node C does not start the route filtering mode or the node C is a non-Level-1-2 router, the node C directly forwards the L1LSPDU to the neighbor node F of the node C.

As shown in fig. 3, the first router is node K. According to the description of the step 210, the node K receives the L2LSPDU issued by the node F, and if the node K does not start the route filtering mode or the node K is a non-Level-1-2 router, the node K directly forwards the L2LSPDU to the neighbor node E of the node K.

Therefore, by applying the method for propagating a link label provided in the embodiment of the present application, after obtaining a link label value of a first designated link, a first router sends a first link state protocol data unit LSPDU to a second router, where the first LSPDU includes the link label value, so that when the second router has started a route filtering mode, or when the second router is a Level-1-2 router, a designated route is determined according to the link label value, and a transmission path corresponding to the designated route includes the first designated link. In this manner, the link label value of a certain link (or links) IS propagated in the IS-IS network, so that other routers in the network recognize the route propagated through the link(s), thereby implementing network control actions such as route filtering, route policy, and the like.

The following is a detailed description by way of an example. As shown in fig. 3, the IS-IS network includes three areas, namely area 1, area 2, and area 3. The node A, the node G, the node C, the node F and the node M are positioned in the area 1; the node E, the node K and the node F are in the area 2; node E and node N are located in region 3. The node A, the node G, the node C, the node M and the node N are Level-1 routers; the node F and the node E are Level-1-2 routers, and the node K is a Level-2 router. The node A and the node M are also configured with IPv4 address prefixes and IPv6 address prefixes.

Within the same region, the link label values are propagated between nodes:

node G receives a user-entered link configuration instruction, G-a link tag value 100. The node G generates an L1LSPDU with a Link-Tag Sub-TLV field populated within a first type TLV field of the L1LSPDU describing the associated Link. The Link label value 100 of the G-a Link is populated in the Link-Tag Sub-TLV field.

Node G sends an L1LSPDU to node C. If the node C does not start the route filtering mode or the node C is a non-Level-1-2 router, the node C does not change the content of the L1LSPDU after receiving the L1LSPDU sent by the node G, and continues to send the L1LSPDU to the neighbor node F.

The Level-1 router or Level-2 router configured with The Link label value propagates The Link label value to other Level-1 routers or Level-2 routers in The same area by filling The Link-Tag Sub-TLV field in The TLV 22 field (The Extended IS responsiveness TLV) or The TLV 222 field (MT intermediary Systems TLV). Wherein the Link-Tag field included in the Link-Tag Sub-TLV field is filled with a corresponding Link Tag value.

In the embodiment of the present application, Link-Tag Sub-TLV fields are defined, as shown in fig. 7, and fig. 7 is a Link-Tag Sub-TLV field schematic diagram provided in the embodiment of the present application. The Link-Tag Sub-TLV field includes three fields: a Type (Type) field, a one byte Type, taking a value of 128; length (Length field), Length of one byte, taking the value of 4; a Link-Tag (Link-Tag) field, a four-byte Link Tag value.

It should be noted that, for a Level-1 router or a Level-2 router configured with a link label value, which one or more of the TLV 22 field and the TLV 222 field IS used to carry the link label value depends on whether the router enables an IS-IS MTR (Multi-Topology Routing) function. For example, when the router is not MTR enabled, the router typically uses the TLV 22 field to carry the link label value. When the router enables the MTR function and deploys both the IPv4 topology and the IPv6 topology, the router normally carries the link label value of the IPv4 link topology by using the TLV 22 field and carries the link label value of the IPv6 topology by using the TLV 222 field.

The method for propagating the link marker provided by the embodiment of the application does not influence the selection mode of the existing router for the TLV 22 field and the TLV 222 field.

In different regions, the link label values are propagated between nodes:

the a-G link flag value of 100 propagates the link flag values between nodes and the link flag value of the G-a link to node F in the same area in the manner described above. Similarly, node F receives a user-entered link configuration instruction, the F-M link flag value 200. The subnet 1 accesses the node A, the IPv6 address prefix of the subnet 1 is 1: 1:/64, the IPv4 address prefix is 1.1.1.0/24. Subnet 2 access node M, subnet 2 IPv6 address prefix 1: 2:/64, IPv4 address prefix 1.1.2.0/24.

Node F calculates that it needs to go through the G-A link to reach subnet 1 (i.e., IPv6 address prefixes 1: 1:/64, IPv4 address prefixes 1.1.1.0/24). And the node F generates an L2LSPDU, wherein the second type TLV fields in the L2LSPDU, which describe the IPv6 address prefix 1: 1:/64 and describe the IPv4 address prefix 1.1.1.0/24, comprise a Link-Tag Sub-TLV field. The Link-Tag field included in the Link-Tag Sub-TLV field populates the Link label value 100 of the G-a Link.

Node F calculates that reaching subnet 2 (i.e., IPv6 address prefixes 1: 2:/64, IPv4 address prefixes 1.1.2.0/24) requires via an F-M link. Node F generates L2LSPDU, wherein the second type TLV fields in L2LSPDU describing IPv6 address prefixes 1: 2:/64 and IPv4 address prefixes 1.1.2.0/24 comprise Link-Tag Sub-TLV fields. The Link-Tag field included in the Link-Tag Sub-TLV field populates the Link label value 200 for the F-M Link.

Node F sends an L2LSPDU to node K. If the node K does not start the route filtering mode or the node K is a non-Level-1-2 router, the node K does not change the content of the L2LSPDU after receiving the L2LSPDU sent by the node F, and continues to send the L2LSPDU to the neighbor node E.

After the node E receives the L2LSPDU sent by the node K (the publisher is still the node F), the calculation needs to pass through the node F to reach the subnet 1 (namely, the IPv6 address prefixes 1: 1:/64 and the IPv4 address prefixes 1.1.1.0/24) and the subnet 2 (namely, the IPv6 address prefixes 1: 2:/64 and the IPv4 address prefixes 1.1.2.0/24).

And the node E generates L1LSPDU, wherein the second type TLV fields in the L1LSPDU, which describe IPv6 address prefixes 1: 1:/64 and 1: 2:/64 and IPv4 external routes 1.1.1.1 and 1.1.1.2, comprise Link-Tag Sub-TLV fields. The Link-Tag Sub-TLV field includes a Link-Tag field that fills a Link Tag value of 100 for the G-a Link and a Link Tag value of 200 for the F-M Link.

Node E sends an L1LSPDU to node N. Node N forwards the L1LSPDU according to its own node role, or alternatively, specifies the route according to the L1LSPDU label.

The Level-1-2 router configured with The Link label value propagates The Link label value to Level-1 routers or Level-2 routers in different regions by filling The Link-Tag Sub-TLV fields in TLV 135(The Extended IP responsiveness TLV, RFC-3784), TLV235 (Multi-Topology readable IPv4 Prefixes TLV, RFC-5120), TLV236 (IPv6 responsiveness TLV, RFC-5308) or TLV237 (Multi-Topology readable IPv6 Prefixes TLV, RFC-5120). Wherein the Link-Tag field included in the Link-Tag Sub-TLV field is filled with a corresponding Link Tag value.

The Link-Tag Sub-TLV field in the embodiment of the present application is shown in FIG. 7. The structure of the Link-Tag Sub-TLV field has been described in detail in the foregoing, and will not be repeated here.

In the embodiment of the present application, an administerable Tag Sub-TLV may be further filled in TLV 135, TLV235, TLV236, and TLV 237. Wherein, the administerive Tag field of the administerive Tag Sub-TLV is filled with the corresponding link Tag value. Of course, it is understood that the administerive Tag Sub-TLV is an existing field. When the link label value is used for marking the IPv6 address prefix or the IPv4 external route, a field describing the IPv6 address prefix or the IPv4 external route has an administive Tag value, and the router uses the link label value to cover the original administive Tag value.

It should be noted that the Level-1-2 router configured with the link label value may adopt any one or more of the TLV 135, the TLV235, the TLV236, and the TLV237 to carry the link label value, depending on whether the router enables an IS-IS MTR (Multi-Topology Routing) function. For example, when the router is not enabled with MTR function and deploys both IPv4 topology and IPv6 topology, the router typically carries the link label value of IPv4 link topology using TLV 135 field and carries the link label value of IPv6 topology using TLV236 field. When the router enables the MTR function and deploys both the IPv4 topology and the IPv6 topology, the router typically carries the link label value of the IPv4 link topology using the TLV235 field and carries the link label value of the IPv6 topology using the TLV237 field.

Based on the same inventive concept, the embodiment of the present application further provides a device for propagating a link marker corresponding to the method for propagating a link marker. Referring to fig. 8, fig. 8 IS a structural diagram of an apparatus for propagating a link label according to an embodiment of the present application, where the apparatus IS applied to a first router, the first router runs an IS-IS protocol, and the first router and a second router are neighbors of each other, and the apparatus includes:

an obtaining unit 810, configured to obtain a link flag value of the first designated link;

a sending unit 820, configured to send a first link state protocol data unit LSPDU to the second router, where the first LSPDU includes the link flag value, so that when the second router has started a route filtering mode, or the second router is a Level-1-2 router, a specified route is determined according to the link flag value, and a transmission path corresponding to the specified route includes the first specified link.

Optionally, the obtaining unit 810 is specifically configured to receive a link configuration instruction input by a user, where the link configuration instruction includes an interface identifier and the link flag value;

determining a first designated link connected with the interface indicated by the interface identifier according to the interface identifier;

alternatively, the first and second electrodes may be,

receiving a second LSPDU sent by a third router which is adjacent to the first router, wherein the second LSPDU comprises a first type TLV which comprises a link topology attribute and the link label value;

determining the first designated link according to the link attribute;

alternatively, the first and second electrodes may be,

receiving a second LSPDU sent by a third router which is adjacent to the first router, wherein the second LSPDU comprises a second type TLV which comprises the link mark value.

Optionally, the sending unit 820 is specifically configured to, when the first router is a Level-1-2 router, or a routing filtering mode of the first router is already started, determine whether to record a specified address prefix locally, where the specified address prefix is reached through the first specified link;

if the specified address is recorded, sending the first LSPDU to the second router;

wherein the first LSPDU comprises a first type TLV, or the first LSPDU comprises a second type TLV, the first type TLV comprising the link topology attribute and the link marker value; the second-type TLV includes an address attribute of the specified address prefix and the link tag value.

Optionally, the sending unit 820 is specifically configured to, when the first router is a Level-1-2 router, or a routing filtering mode of the first router is already started, determine whether to record a specified address prefix locally, where the specified address prefix is reached through the third router;

if the specified address prefix is recorded, the first LSPDU is sent to the second router;

wherein the first LSPDU comprises a second type TLV that includes an address attribute of the specified address prefix and the link tag value.

Optionally, the sending unit 820 is specifically configured to forward the first LSPDU sent by the third router to the second router when the first router does not start a route filtering mode, or the first router is a non-Level-1-2 router;

wherein the first LSPDU comprises a first type TLV, or the first LSPDU comprises a second type TLV.

Optionally, the sending unit 820 is further specifically configured to establish a shortest path tree by using the first router as a root node through a shortest path tree algorithm, where the shortest path tree further includes a plurality of child nodes;

judging whether a child node with the link marking value exists in the shortest path tree or not;

if yes, judging whether the designated address prefix exists in the child node;

if the child node has the specified address prefix, marking a route reaching the specified address prefix as the link marking value.

determining from the shortest path tree whether a first child node having the link marker value exists, the first child node characterizing the third router;

if yes, judging whether the first child node has the specified address prefix or not;

if the first child node has the specified address prefix, judging whether a path reaching the specified address prefix passes through the first child node;

marking a route to the specified address prefix as the link label value if the path to the specified address prefix is through the first child node.

Therefore, by applying the device for propagating a link label provided in the embodiment of the present application, after obtaining a link label value of a first designated link, the device sends a first link state protocol data unit LSPDU to a second router, where the first LSPDU includes the link label value, so that when the second router has started a route filtering mode, or the second router is a Level-1-2 router, a designated route is determined according to the link label value, and a transmission path corresponding to the designated route includes the first designated link. In this manner, the link label value of a certain link (or links) IS propagated in the IS-IS network, so that other routers in the network recognize the route propagated through the link(s), thereby implementing network control actions such as route filtering, route policy, and the like.

Based on the same inventive concept, the present application further provides a network device, as shown in fig. 9, including a processor 910, a transceiver 920, and a machine-readable storage medium 930, where the machine-readable storage medium 930 stores machine-executable instructions capable of being executed by the processor 910, and the processor 910 is caused by the machine-executable instructions to perform the method for propagating link marking provided in the present application. The apparatus for propagating link labels shown in fig. 8 can be implemented by using a hardware structure of a network device as shown in fig. 9.

The computer-readable storage medium 930 may include a Random Access Memory (RAM) or a Non-volatile Memory (NVM), such as at least one disk Memory. Alternatively, the computer-readable storage medium 930 may also be at least one storage device located remotely from the processor 910.

The Processor 910 may be a general-purpose Processor, and includes a Central Processing Unit (CPU), a Network Processor (NP), and the like; the Integrated Circuit can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components.

In embodiments of the present application, the processor 910, by reading machine executable instructions stored in the machine readable storage medium 930, is caused by the machine executable instructions to implement the method of propagating link markers described in embodiments of the present application described above, which can be performed by the processor 910 itself and the call transceiver 920.

Additionally, the present application provides a machine-readable storage medium 930, where the machine-readable storage medium 930 stores machine-executable instructions, which when invoked and executed by the processor 910, cause the processor 910 itself and the invoking transceiver 920 to perform the method of propagating link markers described in the present application embodiment.

The implementation process of the functions and actions of each unit in the above device is specifically described in the implementation process of the corresponding step in the above method, and is not described herein again.

For the device embodiments, since they substantially correspond to the method embodiments, reference may be made to the partial description of the method embodiments for relevant points. The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of the application. One of ordinary skill in the art can understand and implement it without inventive effort.

For the embodiments of the apparatus for propagating a link mark and the machine-readable storage medium, since the contents of the related methods are substantially similar to the foregoing embodiments of the methods, the description is relatively simple, and reference may be made to the partial description of the embodiments of the methods for relevant points.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A method of propagating a link label, the method being applied to a first router running an IS-IS protocol, the first router and a second router being neighbors of each other, the method comprising:

acquiring a link marking value of a first designated link;

sending a first Link State Protocol Data Unit (LSPDU) to the second router, wherein the first LSPDU comprises the link flag value, so that when the second router starts a route filtering mode, or the second router is a Level-1-2 router, a designated route is determined according to the link flag value, and a transmission path corresponding to the designated route comprises the first designated link;

the sending a first link state protocol data unit LSPDU to the second router specifically includes:

when the first router is a Level-1-2 router or the first router opens a route filtering mode, judging whether a specified address prefix is recorded locally or not, wherein the specified address prefix arrives through the first specified link;

wherein the first LSPDU comprises a first type TLV, or the first LSPDU comprises a second type TLV, the first type TLV comprising a link topology attribute and the link label value; the second-type TLV includes an address attribute of the specified address prefix and the link tag value.

2. The method according to claim 1, wherein the obtaining the link flag value of the first specified link specifically includes:

receiving a link configuration instruction input by a user, wherein the link configuration instruction comprises an interface identifier and the link marker value;

alternatively, the first and second electrodes may be,

receiving a second LSPDU sent by a third router which is adjacent to the first router, wherein the second LSPDU comprises a first type TLV which comprises a link topology attribute and the link mark value;

and determining the first designated link according to the link topology attribute.

3. The method according to claim 1, wherein the obtaining the link flag value of the first specified link specifically includes:

4. The method of claim 3, wherein the sending a first Link State Protocol Data Unit (LSPDU) to the second router specifically comprises:

when the first router is a Level-1-2 router or a routing filtering mode of the first router is started, judging whether a specified address prefix is recorded locally or not, wherein the specified address prefix is reached through the third router;

5. The method of claim 3, wherein the sending a first Link State Protocol Data Unit (LSPDU) to the second router specifically comprises:

when the first router does not start a route filtering mode, or the first router is a non-Level-1-2 router, forwarding the first LSPDU sent by the third router to the second router;

wherein the first LSPDU comprises a first type TLV, or the first LSPDU comprises a second type TLV; the first type TLV includes the link topology attribute and the link label value, and the second type TLV includes the address attribute specifying the address prefix and the link label value.

6. The method according to claim 1, wherein the determining whether the specified address prefix is recorded locally specifically includes:

establishing a shortest path tree by using the first router as a root node through a shortest path tree algorithm, wherein the shortest path tree further comprises a plurality of child nodes;

if yes, judging whether the designated address prefix exists in the child node;

7. The method according to claim 4, wherein the determining whether the specified address prefix is recorded locally specifically includes:

if the first child node has the appointed address prefix, judging whether a path reaching the appointed address prefix passes through the child node;

8. An apparatus for propagating link labels, the apparatus being applied to a first router running an IS-IS protocol, the first router and a second router being neighbors of each other, the apparatus comprising:

a sending unit, configured to send a first link state protocol data unit to the second router, where the first LSPDU includes the link flag value, so that when the second router has started a route filtering mode, or the second router is a Level-1-2 router, a designated route is determined according to the link flag value, and a transmission path corresponding to the designated route includes the first designated link;

the sending unit is specifically configured to,

when the first router is a Level-1-2 router or a routing filtering mode of the first router is started, judging whether a specified address prefix is recorded locally or not, wherein the specified address prefix is reached through the first specified link;

9. The apparatus according to claim 8, characterized in that the acquisition unit is specifically configured to,

alternatively, the first and second electrodes may be,

10. The apparatus according to claim 8, characterized in that the acquisition unit is specifically configured to,

11. The device according to claim 10, characterized in that the sending unit is specifically configured to,

when the first router is a Level-1-2 router or a routing filtering mode of the first router is started, judging whether a specified address prefix is recorded locally or not, wherein the specified address prefix is reached through a third router;

12. The device according to claim 10, characterized in that the sending unit is specifically configured to,

when the first router does not start a route filtering mode, or the first router is a non-Level-1-2 router, forwarding the first LSPDU sent by a third router to the second router;

wherein the first LSPDU comprises a first type TLV, or the first LSPDU comprises a second type TLV; the first type TLV includes the link topology attribute and the link label value, and the second type TLV includes the address attribute of the specified address prefix and the link label value.

13. The apparatus of claim 8, wherein the sending unit is further configured to,

if yes, judging whether the designated address prefix exists in the child node or not;

14. The apparatus according to claim 11, characterized in that the sending unit is further specifically configured to,