CN117135105A - Method and device for forwarding hierarchical BIER multicast message - Google Patents

Abstract

The invention relates to the technical field of BIER multicast, in particular to a method and a device for forwarding a layered BIER multicast message. Comprising the following steps: dividing a BIER multicast domain into at least two layers, wherein each layer comprises at least one subdomain, and publishing BIER layer information notification by crossing the layer BFR nodes and neighbor nodes thereof; learning level information and sub-domain information of each sub-domain on a cross-level BFR node, and constructing a level forwarding table, a forwarding routing table of each sub-domain and an extended BIFT forwarding table of each sub-domain according to the learned level information and sub-domain information; and packaging the BIER header information and forwarding the BIER header information layer by layer, wherein the BIER header information comprises a layer BIER header field. The invention can reduce the BIFT entry requirement of each forwarding, lighten the performance pressure of bearing equipment and solve the forwarding efficiency problem existing when operators hierarchically deploy BIER.

Description

Method and device for forwarding hierarchical BIER multicast message

Technical Field

The invention relates to the technical field of BIER multicast, in particular to a method and a device for forwarding a layered BIER multicast message.

Background

The bit index display replication (bit indexed explicit replication, abbreviated BIER) technique is one of the multicast techniques for constructing multicast forwarding paths. The technology provides a multicast technical architecture for constructing a multicast distribution tree, can bear Ethernet, IPv4, IPv6 and VPN programming services, and can be applied to IPTV live broadcast, 5G MBS, industry live broadcast and other service scenes. BIER, a new multicast scheme, has become one of the main candidates for carrier IPTV service bearers.

BIER multicast message forwarding architecture is defined in the standard RFC8279 of the internet engineering task force (The Internet Engineering Task Force, abbreviated IETF). And defines in the working group draft "draft-ietf-beer-bieri 6-05" that a BIER message header is added in an internet protocol version 6 (Internet Protocol Version 6, abbreviated as IPv 6) message of non-multiprotocol label switching (Multi-protocol Label Switching, abbreviated as MPLS) to achieve the purpose of transmitting BIER multicast messages in an IPv6 network.

The BIER architecture defined in RFC8279 is single-level. When a large-scale network is deployed, a large number of BIER forwarding router identifiers (BIER Forwarding Router Identifier, abbreviated as BFR-IDs) are required to be planned and deployed and used for identifying BFR routers, so that the problems of more entries of a BIER message forwarding table, increased length of a BIER index bit string (BitString) and the like seriously affecting the forwarding efficiency of BIER multicast messages are caused.

In view of this, how to overcome the defects existing in the prior art, and solve the problem that the forwarding efficiency of the existing BIER multicast message is low, is a problem to be solved in the technical field.

Disclosure of Invention

Aiming at the defects or improvement demands of the prior art, the invention solves the problem of low forwarding efficiency of BIER multicast messages caused by more entries of the BIER message forwarding table and increased length of the BIER index bit string.

The embodiment of the invention adopts the following technical scheme:

in a first aspect, the present invention provides a method for forwarding a hierarchical BIER multicast message, specifically: dividing a BIER multicast domain into at least two layers, wherein each layer comprises at least one subdomain, and publishing BIER layer information notification by crossing the layer BFR nodes and neighbor nodes thereof; learning level information and sub-domain information of each sub-domain on a cross-level BFR node, and constructing a level forwarding table, a forwarding routing table of each sub-domain and an extended BIFT forwarding table of each sub-domain according to the learned level information and sub-domain information; and packaging the BIER header information and forwarding the BIER header information layer by layer, wherein the BIER header information comprises a layer BIER header field.

Preferably, the dividing the BIER multicast domain into at least two layers specifically includes: according to the core convergence of the network topology and the hierarchical structure of access, the IGP process domain of each layer is divided into a hierarchy.

Preferably, the cross-layer BFR node and its neighbor node issue BIER layer information advertisement, which specifically includes: adding a sub-sub-TLV for identifying the BIER-LEVEL Type in Info-sub-TLV of the message, wherein the Type value of the sub-sub-TLV represents the BIER LEVEL capability, and the value part of the sub-sub-TLV comprises the BIER LEVEL and subdomain information; an IGP notification message is issued between the cross-layer BFR node and the neighbor nodes thereof, wherein the IGP notification message carries info-sub-tlv and BIER LEVEL type sub-sub-tlv.

Preferably, the learning the hierarchical information and the sub-domain information of each sub-domain on the cross-hierarchical BFR node specifically includes: the cross-level BFR node analyzes the received level information notice and acquires the level information, topology information and BitString information of each subdomain according to the sub-sub-TLV in the notice.

Preferably, the building a hierarchical forwarding table, a forwarding routing table of each subdomain and an extended BIFT forwarding table of each subdomain according to the learned hierarchical information and subdomain information specifically includes: constructing a hierarchical forwarding table according to the hierarchical id, the subdomain id, the export BIER hierarchical id and the BitString; generating a corresponding routing table item according to the hierarchical id and the id of the subdomain BIFT, judging the next-hop neighbor of the routing table item, and updating the routing table item in the forwarding routing table according to the next-hop neighbor information; and constructing an extended BIFT forwarding table of the subdomain according to the hierarchical id, the id of the subdomain BIFT, the subdomain id, the id of the BFR, the BP and the next hop neighbor.

Preferably, the specific: the fields in the BIER header information include: an outer layer IP header, a hierarchical BIER header, and an IP multicast stream, wherein an RSV field in the hierarchical BIER header identifies the hierarchical id and a BitString field identifies the BitString of each subdomain.

Preferably, the encapsulating BIER header information and forwarding the BIER header information layer by layer specifically includes: after receiving the BIER encapsulation message, the cross-layer BFR node inquires a BIFT forwarding table of the sub-domain of the layer, and inquires the layer forwarding table after stripping the BIER header, encapsulates sub-domain information to be forwarded in the layer BIER header, and forwards the message to a neighbor node in the next sub-domain through a corresponding interface in the layer forwarding table; after receiving the message forwarded by the cross-level BFR node, the neighbor node in the next sub-domain extracts the sub-domain information in the BIER header of the message, and inquires the extended BIFT forwarding table of the corresponding sub-domain to forward the message.

Preferably, the message forwarding is performed by querying an extended BIFT forwarding table of a corresponding subdomain, which specifically includes: extracting a layer id, an id of a subdomain BIFT and a BitString from the message, inquiring an extended BIFT forwarding table, and obtaining an output interface of the message and BIER header information packaged in the message; and (3) packaging and forwarding the message according to the attribute of the next hop, and clearing the BitString by using the BM corresponding to the NBR until the BitString is empty.

Preferably, the message packaging and forwarding according to the attribute of the next hop specifically includes: when the message is an exit router message, copying the message, updating the message package, and forwarding the message to a neighbor node in the next layer from the appointed interface; and when the message is not the message of the exit router, stripping BIER header information packaged in the message, and implementing IP multicast forwarding.

On the other hand, the invention provides a device for forwarding a layering BIER multicast message, which specifically comprises: the method comprises the steps of connecting at least one processor with a memory through a data bus, wherein the memory stores instructions executed by the at least one processor, and the instructions are used for completing the method for forwarding the layering BIER multicast message in the first aspect after being executed by the processor.

Compared with the prior art, the embodiment of the invention has the beneficial effects that: the hierarchical BIER forwarding architecture is constructed, the BIER domain is divided into a plurality of subdomains, each subdomain uses a respective message forwarding table to forward, the BIFT entry requirement for each forwarding is reduced, the performance pressure of bearing equipment is reduced, and the forwarding efficiency problem existing in the hierarchical deployment of BIER by an operator is solved.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present invention, the drawings that are required to be used in the embodiments of the present invention will be briefly described below. It is evident that the drawings described below are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.

Fig. 1 is a schematic topology diagram of a telecommunications metropolitan area network carrying IPTV services in an embodiment of the present invention;

fig. 2 is a flowchart of a method for forwarding a hierarchical BIER multicast packet according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a sub-sub-tlv for identifying BIER-LEVEL types according to an embodiment of the present invention;

fig. 4 is a schematic diagram of fields in BIER header information according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a reserved field RSV in a hierarchical BIER header according to an embodiment of the present invention;

FIG. 6 is a hierarchical forwarding representation intent provided by an embodiment of the present invention;

fig. 7 is a schematic diagram of a construction process of a forwarding routing table according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a BIFT forwarding table according to an embodiment of the present invention;

FIG. 9 is a flowchart of a process for forwarding a hierarchical BIER multicast message according to an embodiment of the present invention;

fig. 10 is a schematic structural diagram of a device for forwarding a hierarchical BIER multicast message according to an embodiment of the present invention;

wherein, the reference numerals are as follows:

11: a processor; 12: a memory.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

The present invention is an architecture of a specific functional system, so that in a specific embodiment, functional logic relationships of each structural module are mainly described, and specific software and hardware implementations are not limited.

In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other. The invention will be described in detail below with reference to the drawings and examples.

Some terms used in the embodiments of the present invention are explained as follows:

(1) BIER: bit Indexed Explicit Replication, the bit index shows a copy. The network domain supporting BIER forwarding is called BIER domain, in which multiple subfields can be included.

(2) BFR: bit Forwarding Router, bit forwarding router. Routers that support BIER technology are all referred to as BFRs.

(3) BFIR: bit Forwarding Ingress Router, bit forwarding ingress router. When the BFR acts as an ingress router for the BIER domain, it is referred to as BFIR.

(4) BFER: bit Forwarding Engress Router, bit forwarding egress router. When a BFR acts as an egress router for the BIER domain, it is referred to as a BFER. BFIR and BFER are collectively referred to as edge BFRs or edge devices, being source or destination nodes in the BIER domain.

(5) BFR-ID: BIER Forwarding Router Identifier BIER forwards the router identifier. In the BIER domain, in units of BIER subfields, the edge node of each BIER subfield needs to be configured with a BFR-ID value that is unique within the BIER subfield.

(6) BitString: and indexing the bit string. Expressed as an integer in the range of 1 to 65535, each BFR-ID would be mapped to a bit in BitString. When forwarding, the BFR position or index represented by each Bit in the BitString represents a destination node.

(7) BIFT: bit Index Forwarding Table bit index forwarding table. For associating BFR-IDs with bits in BitString.

(8) BP: bitPosition, bit position. Representing one bit in BitString, each edge device in the BIER domain floods the allocated unique BP, and all BIER forwarding devices use the unicast forwarding routing table to perform routing computation.

(9) NBR: neighbor, neighbor node. Representing the next-hop neighbor of a certain BFR-ID.

(10) BM: bitMask, set of destination nodes. The BitString formed by the BFR-IDs of the destination nodes forms a destination node set, which represents a BIER domain edge node set reachable through the neighbor when the message is sent to the next hop neighbor replication.

(11) BRT: BIER Router Table, forwarding routing table. For guiding route forwarding.

Example 1:

BIER is a bit index display multicast forwarding technique, the carried service is IP multicast stream, and its data payload is IP multicast stream. As a new multicast scheme, it becomes one of the main candidate schemes for operators to carry services such as live broadcast, IPTV, etc. Taking IPTV service AS an example, it is generally planned to deploy a BIER domain carrying IPTV service across AS and IGP. Currently, there is no solution across BIER domain and BIER subdomain, no BIER domain information in the BIER header, and subdomain interworking can only use the OPTION-A scheme. Because the number of BFRs in the BIER domain is large, the number of network nodes of one operator can be about 40000, and each BitString and BIFT need to contain all BFRs, so that the BitString needs more digits, the BIFT needs more table entries, and the requirement on the processing capacity of equipment is higher.

In the topology of the telecom metropolitan area network carrying IPTV service as shown in fig. 1, if the BIER subdomains are not hierarchically divided, all routers in the topology need to be deployed in the same BIER subdomain, so that the number of BFR routers in one BIER subdomain is large, and the problem is that BIER forwarding entries are increased, thereby affecting forwarding efficiency, and simultaneously increasing equipment storage and processing resource consumption and equipment cost. In this embodiment, for convenience of description, a specific implementation process of the method is described by taking the network topology in fig. 1 as an example, and in an actual implementation, the implementation process may be adjusted, expanded and optimized according to the actual network topology and service requirements according to the method principles provided in this embodiment.

In order to solve the above problem, as shown in fig. 2, the method for forwarding the hierarchical BIER multicast message provided in the embodiment of the present invention specifically includes the following steps.

Step 101: the BIER multicast domain is divided into at least two layers, each layer contains at least one subdomain, and BIER layer information notification is issued across the layer BFR nodes and their neighbor nodes.

In specific implementation, different schemes can be adopted according to actual network topology. One possible solution is to divide an interior gateway protocol (Interior Gateway Protocol, abbreviated IGP) process domain, divide the IGP process domain of each layer into a hierarchy (BIER Level) according to a hierarchical structure of core aggregation and access of the network topology, and set a Level id (Level id) for each Level. To facilitate distinguishing subdomains of different levels, level information may be added to the subdomain id. For example, the hierarchical structure of core aggregation and access shown in fig. 1 may demarcate two BIER hierarchies in one BIER multicast domain. BIER subfield 1, where R1, R2, R3, R4 are 0 layers, denoted SD0-1, indicates that this subfield is the 1 st subfield in layer 0. R3, R4, R11, R12, R13 are BIER subdomains 1 of level 1, denoted SD 1-1. R3, R4, R21, R22, R23 are BIER subdomains 2 of level 1, denoted SD1-2. Wherein R3 and R4 are cross-level BFR nodes between level 0 and level 1.

In order to perform cross-level forwarding, the cross-level BFR node needs to learn level information of the same level and sub-domain information of each sub-domain. For example, in FIG. 1, the SD0-1 subdomain of level 0 requires learning BIER level topology information for the SD1-1 and SD1-2 subdomains of level 1. In this embodiment, the cross-level BFR node issues the level information of the sub-domain to the neighbor nodes in other levels, and the neighbor nodes that receive the issued information learn the level information through the notification message. Specifically, in order to issue the corresponding information, the hierarchical information and the topology information of each subdomain may be added to the header, the hierarchical information may be carried by the subdomain id in the header or an individual hierarchical information field, and the topology information may be carried by the BitString field in the header.

Step 102: and learning the hierarchical information and the sub-domain information of each sub-domain on the cross-hierarchical BFR nodes, and constructing a hierarchical forwarding table, a forwarding routing table of each sub-domain and an extended BIFT forwarding table of each sub-domain according to the learned hierarchical information and sub-domain information.

After the release notice in step 101 is received, the cross-level BFR node analyzes the received level information notice, acquires the level information, topology information and BitString information of each subdomain according to the sub-sub-TLV in the notice, and constructs a level forwarding table, a forwarding routing table of each subdomain and an extended BIFT forwarding table of each subdomain according to the information. In the step 101, the BIER domain is divided into a plurality of layers, and the forwarding information of other layers is not required to be acquired in each layer, so in this embodiment, the bit forwarding table and the BitString of each sub-domain only need to include the forwarding information of the sub-domain, thereby reducing the number of entries of the bit forwarding table and the length of the BitString, improving the forwarding efficiency, and reducing the requirement on the performance of forwarding equipment.

The cross-level BFR node R3 between the level 0 and the level 1 can directly acquire the level information of the level 0 where the BFR node R3 is located, and learn the BIER level information of the SD1-1 and SD1-2 subdomains in the level 1 through the BFR neighbor nodes R11 and R21; meanwhile, BIER subdomain topology information of SD0-1/SD1-1/SD1-2, such as BitString information of each subdomain, is also learned. After the R3 learns the information, the information can be filled into corresponding table entries, and the guide message is forwarded according to the contents of the table entries.

Step 103: and packaging the BIER header information and forwarding the BIER header information layer by layer, wherein the BIER header information comprises a layer BIER header field.

Based on the level information and the sub-domain information learned in the step 102, the built level forwarding table, the forwarding routing table of each sub-domain and the extended BIFT forwarding table of each sub-domain, the cross-domain service regeneration can be realized, so that the BIER multicast message forwarding flow is optimized, and the hierarchical BIER multicast message forwarding is supported.

Specifically, in the IP communication network, the network topology information is advertised by the IGP protocol, so in practical implementation, BIER hierarchical topology information advertisement can be implemented by extending the IGP protocol, and in this embodiment, BIER hierarchical information is added based on extending the BIER header structure of the IGP/BGP protocol, so as to perform the publishing and trans-hierarchical forwarding of the hierarchical information. Specifically, as shown in fig. 4, fields in BIER header information include: an outer layer IP header, a hierarchical BIER header, and an IP multicast stream. Further, as shown in fig. 5, the reserved field RSV field in the hierarchy BIER header may identify the hierarchy id, or the newly added extension field represents the BIER field; the BitString field identifies the BitString of each subdomain and encapsulates the BitString of each subdomain; in the method provided by the embodiment, each subdomain uses one BIFT, subdomain BIFT of different subdomains are distinguished by id, and the BIFT-id field identifies the id of the subdomain BIFT; each subdomain uses one BFIR, the BFIR of the different subdomains being distinguished by an id, the BFIR-id identifying the id of the subdomain BFIR.

Through steps 101-103 provided in this embodiment, the hierarchical packet deploys the BIER subdomain, expands the BIER header, supports hierarchical type BitString, expands standard BIER forwarding flow and protocol interaction procedure,

in this embodiment, the publishing of the hierarchical information in step 101 may be accomplished by extending the IGP protocol. Taking intermediate system-to-intermediate system routing protocol (Intermediate System to Intermediate System, abbreviated as ISIS) protocol as an example, RFC8401 defines Sub-domain information release of BIER, and adopts a manner that IS-IS Reachability Prefix TLV carries BIER Info Sub-TLVs, and each BIER Info Sub-TLV contains a Sub-domain-id. On this basis, the sub-TLV of the newly added BIER Level capability may be extended to support advertisement of BIER Level information. Further, the capability of issuing BIER Level between different layers may be issued through a sub-sub-TLV of BIER Info sub-TLV, as shown in fig. 3, a sub-sub-TLV for identifying BIER-Level Type is added in Info-sub-TLV of the message, where a Type value of the sub-sub-TLV indicates BIER Level capability, and a value part of the sub-sub-TLV, that is, a BIER-Level-SD field, includes BIER Level and subdomain information. An IGP notification message is issued between the cross-layer BFR node and the neighbor nodes thereof, wherein the IGP notification message carries info-sub-tlv and BIER LEVEL type sub-sub-tlv. For example, in the topology of fig. 1, IGP neighbors are established between router R3 and router R11. The IGP notification messages issued by R3 and R11 carry info-sub-tlv and BIER LEVEL type sub-sub-tlv, wherein LEVEL represents a hierarchical id and subdomain-id represents a subdomain id. Where sub-sub-tlv is type 09 (identifying BIER LEVEL type), value is level=1, and subdomain-id=1. Similarly, the value carried in the BIER LEVEL type sub-sub-tlv issued between R3 and R21 is level=1 and subdomain=2.

The cross-level BFR node learns the level information and the subdomain information according to the notification, and constructs a level forwarding table, a forwarding routing table of each subdomain and a BIFT forwarding table according to the process described by the RFC8279 standard according to the learned level information and subdomain information.

(1) The hierarchical forwarding table is used for cross-hierarchical forwarding, and is constructed according to the hierarchical id, the subdomain id, the export BIER hierarchical id and the BitString. For example, the table entry format of the hierarchical forwarding table generated by R3 according to the learned BIER hierarchical information is shown in fig. 6.

(2) And (3) forwarding a routing table, wherein in the construction process shown in fig. 7, a corresponding routing table item is generated according to the level id and the id of the subdomain BIFT, the next-hop neighbor of the routing table item is judged, and the routing table item is updated according to the next-hop neighbor information.

(3) And constructing an extended BIFT forwarding table of the subdomain according to the hierarchical id, the id of the subdomain BIFT, the subdomain id, the id of the BFR, the BP and the next hop neighbor. For example, the BIFT forwarding table entry generated by R3 is shown in FIG. 8.

Through the process, the list items required by the cross-level forwarding can be established on each cross-level BFR node so as to know the cross-domain forwarding of the message.

As shown in fig. 9, the specific forwarding procedure is:

step 201: after receiving the BIER encapsulation message, the cross-layer BFR node inquires a BIFT forwarding table of the sub-domain of the layer, and inquires the layer forwarding table after stripping the BIER header, encapsulates sub-domain information to be forwarded in the layer BIER header, and forwards the message to a neighbor node in the next sub-domain through a corresponding interface in the layer forwarding table.

In this embodiment, by expanding the IGP protocol, the sub-sub-TLV is used to carry the level information in the BIER header, and establish the level forwarding table, the trans-level BFR node performs proxy answering according to the level information, and performs inter-level forwarding according to the level forwarding table, so as to implement trans-level forwarding.

Step 202: after receiving the message forwarded by the cross-level BFR node, the neighbor node in the next sub-domain extracts the sub-domain information in the BIER header of the message, and inquires the extended BIFT forwarding table of the corresponding sub-domain to forward the message.

And forwarding in the hierarchy according to the BIER protocol, the information of the subdomains in the BIER header and the extended BIFT forwarding table of each subdomain. Specifically, extracting a layer id, an id of a subdomain BIFT and BitString in the message, querying an extended BIFT forwarding table, and obtaining an output interface of the message and BIER header information packaged in the message. And (3) packaging and forwarding the message according to the attribute of the next hop, and clearing the BitString by using the BM corresponding to the NBR until the BitString is empty.

Further, in the forwarding process, in order to perform cross-layer forwarding, different processes are required according to the type of the message. Specific: when the message is an exit router message ending at the BIER Proxy node, the message is copied, one copy is uploaded, one copy is copied to the next level, the message is updated and packaged, and the message is forwarded to the neighbor node in the next level from the appointed interface. And when the message is not the message of the exit router, stripping BIER header information packaged in the message, and implementing IP multicast forwarding.

Through steps 201-202, BIER information can be redistributed in different layers, cross-domain forwarding similar to label switching is realized according to BIER agent forwarding tables among subdomains of different layers, and forwarding in each layer is completed.

In the topology shown in fig. 1, the content server outside the BIER domain sends the IP multicast stream packet to the head-end router R1 of the BIER domain, and forwards the packet to R23 in the BIER domain, where the forwarding procedure is as follows.

The source IP multicast message entering R1 does not contain hierarchy information and subdomain information as follows.

Source ip=10.1.1.1
	Group ip= 225.0.0.1
Date=media content data

And R1 learns the layer information and the subdomain information of the IP multicast message according to the broadcast message of R3, encapsulates the 0-layer BIER header information and forwards the information to R3. In the encapsulated packet, RSV field=0 in BIER header, which indicates a hierarchy of 0 layers.

According to step 201, after receiving the BIER encapsulation packet, R3 queries the 0-layer subfield BIFT forwarding table, and peels off the BIER header to obtain the next packet.

Source ip=10.1.1.1
	Group ip= 225.0.0.1
Date=media content data

And R3 queries a hierarchical forwarding table, encapsulates 1-layer SD1-1 subdomain information, forwards the message to R11 through a corresponding interface, encapsulates 1-layer SD1-2 subdomain information, and forwards the message to R11 and R21 through multicast of the corresponding interface.

The encapsulated message sent to R11 is shown below.

The encapsulated message sent to R21 is shown below.

R11 and R23 are not in a sub-domain, and the forwarding is finished.

According to step 202, R21 and R23 are in the same sub-domain for intra-domain forwarding. After receiving the BIER encapsulation message forwarded by R3, extracting level-id=1 and shift-id information in the BIER encapsulation in the message, querying an extended BIFT forwarding table as shown in fig. 8 to perform BIER encapsulation, and forwarding the message to R23.

As can be seen from the above process, the method provided in this embodiment can complete forwarding of the multi-level BIER multicast message.

Compared with the prior art, the method for forwarding the layering BIER multicast message has the following advantages: (1) The hierarchical forwarding architecture provided by the embodiment reduces the number of BFR routers in a single BIER subzone and simplifies BFR-ID planning and deployment of a large-scale network. (2) The hierarchical forwarding architecture provided by the embodiment reduces bit string length and forwarding table entries in the BIER subdomain, improves the forwarding efficiency of BIER multicast messages, and reduces the requirements of equipment computing and storage resources.

Example 2

On the basis of the method for forwarding the hierarchical BIER multicast message in the foregoing embodiment 1 to the method provided by the present invention, the present invention further provides a device for forwarding the hierarchical BIER multicast message, as shown in fig. 10, which is a schematic device architecture diagram of an embodiment of the present invention. The apparatus for forwarding the hierarchical BIER multicast message in this embodiment includes one or more processors 11 and a memory 12. In fig. 10, a processor 11 is taken as an example.

The processor 11 and the memory 12 may be connected by a bus or otherwise, which is illustrated in fig. 10 as a bus connection.

Memory 12 serves as a non-volatile computer readable storage medium for a hierarchical BIER multicast message forwarding method, and may be used to store non-volatile software programs, non-volatile computer executable programs, and modules, such as the hierarchical BIER multicast message forwarding method of embodiment 1. The processor 11 executes various functional applications and data processing of the apparatus for forwarding the hierarchical BIER multicast message by running nonvolatile software programs, instructions and modules stored in the memory 12, that is, implements the method for forwarding the hierarchical BIER multicast message of embodiment 1.

Memory 12 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 12 may optionally include memory located remotely from processor 11, which may be connected to processor 11 via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The program instructions/modules are stored in the memory 12 and when executed by the one or more processors 11 perform the method of hierarchical BIER multicast message forwarding in embodiment 1 described above, for example, performing the steps shown in fig. 2, 7 and 9 described above.

Those of ordinary skill in the art will appreciate that all or a portion of the steps in the various methods of the embodiments may be implemented by a program that instructs associated hardware, the program may be stored on a computer readable storage medium, the storage medium may include: read Only Memory (ROM), random access Memory (Random Access Memory, RAM), magnetic disk or optical disk.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims (10)

1. The method for forwarding the hierarchical BIER multicast message is characterized by comprising the following steps of:

dividing a BIER multicast domain into at least two layers, wherein each layer comprises at least one subdomain, and publishing BIER layer information notification by crossing the layer BFR nodes and neighbor nodes thereof;

learning level information and sub-domain information of each sub-domain on a cross-level BFR node, and constructing a level forwarding table, a forwarding routing table of each sub-domain and an extended BIFT forwarding table of each sub-domain according to the learned level information and sub-domain information;

and packaging the BIER header information and forwarding the BIER header information layer by layer, wherein the BIER header information comprises a layer BIER header field.

2. The method for forwarding the hierarchical BIER multicast message according to claim 1, wherein the dividing the BIER multicast domain into at least two layers specifically comprises:

according to the core convergence of the network topology and the hierarchical structure of access, the IGP process domain of each layer is divided into a hierarchy.

3. The method for forwarding the hierarchical BIER multicast message according to claim 1, wherein the trans-hierarchical BFR node and its neighbor node issue BIER hierarchical information advertisement, specifically comprising:

adding a sub-sub-TLV for identifying the BIER-LEVEL Type in Info-sub-TLV of the message, wherein the Type value of the sub-sub-TLV represents the BIER LEVEL capability, and the value part of the sub-sub-TLV comprises the BIER LEVEL and subdomain information;

an IGP notification message is issued between the cross-layer BFR node and the neighbor nodes thereof, wherein the IGP notification message carries info-sub-tlv and BIER LEVEL type sub-sub-tlv.

4. The method for forwarding the hierarchical BIER multicast message according to claim 1, wherein learning the hierarchical information and the sub-domain information of each sub-domain on the trans-hierarchical BFR node specifically includes:

the cross-level BFR node analyzes the received level information notice and acquires the level information, topology information and BitString information of each subdomain according to the sub-sub-TLV in the notice.

5. The method for forwarding the hierarchical BIER multicast message according to claim 1, wherein the constructing a hierarchical forwarding table, a forwarding routing table of each sub-domain and an extended BIFT forwarding table of each sub-domain according to the learned hierarchical information and sub-domain information specifically includes:

constructing a hierarchical forwarding table according to the hierarchical id, the subdomain id, the export BIER hierarchical id and the BitString;

generating a corresponding routing table item according to the hierarchical id and the id of the subdomain BIFT, judging the next-hop neighbor of the routing table item, and updating the routing table item in the forwarding routing table according to the next-hop neighbor information;

and constructing an extended BIFT forwarding table of the subdomain according to the hierarchical id, the id of the subdomain BIFT, the subdomain id, the id of the BFR, the BP and the next hop neighbor.

6. The method for forwarding the hierarchical BIER multicast message according to claim 1, wherein the method is specifically:

the fields in the BIER header information include: an outer layer IP header, a hierarchical BIER header, and an IP multicast stream, wherein an RSV field in the hierarchical BIER header identifies the hierarchical id and a BitString field identifies the BitString of each subdomain.

7. The method for forwarding the hierarchical BIER multicast message according to claim 1, wherein the encapsulating BIER header information and forwarding the BIER header information layer by layer specifically includes:

after receiving the BIER encapsulation message, the cross-layer BFR node inquires a BIFT forwarding table of the sub-domain of the layer, and inquires the layer forwarding table after stripping the BIER header, encapsulates sub-domain information to be forwarded in the layer BIER header, and forwards the message to a neighbor node in the next sub-domain through a corresponding interface in the layer forwarding table;

after receiving the message forwarded by the cross-level BFR node, the neighbor node in the next sub-domain extracts the sub-domain information in the BIER header of the message, and inquires the extended BIFT forwarding table of the corresponding sub-domain to forward the message.

8. The method for forwarding the hierarchical BIER multicast message according to claim 7, wherein the querying the extended BIFT forwarding table of the corresponding subdomain for forwarding the message specifically includes:

extracting a layer id, an id of a subdomain BIFT and a BitString from the message, inquiring an extended BIFT forwarding table, and obtaining an output interface of the message and BIER header information packaged in the message;

and (3) packaging and forwarding the message according to the attribute of the next hop, and clearing the BitString by using the BM corresponding to the NBR until the BitString is empty.

9. The method for forwarding the hierarchical BIER multicast message according to claim 8, wherein the message encapsulation and forwarding are performed according to the attribute of the next hop, specifically including:

when the message is an exit router message, copying the message, updating the message package, and forwarding the message to a neighbor node in the next layer from the appointed interface;

and when the message is not the message of the exit router, stripping BIER header information packaged in the message, and implementing IP multicast forwarding.

10. The utility model provides a device that layering BIER multicast message was forwarded which characterized in that:

the method for forwarding the hierarchical BIER multicast message according to any one of claims 1-9, comprising at least one processor and a memory, said at least one processor and memory being connected by a data bus, said memory storing instructions for execution by said at least one processor, said instructions, after being executed by said processor, for performing the method for forwarding the hierarchical BIER multicast message.