WO2024067339A1 - Multicast traffic packet forwarding method and system, computer device, and readable medium - Google Patents

Abstract

The present disclosure provides a multicast traffic packet forwarding method, comprising: a bit forwarding ingress router (BFIR) receiving multicast traffic cross-AS forwarding information notified by a controller; and carrying the multicast traffic cross-AS forwarding information in a traffic packet to be forwarded to generate a first multicast traffic packet, wherein the first multicast traffic packet carries a base header and an extension header, information carried in the extension header of the first multicast traffic packet is obtained according to the multicast traffic cross-AS forwarding information, and the information of the extension header is used for indicating that the multicast traffic packet is forwarded at a downstream AS of an AS to which the BFIR belongs. The present disclosure further provides a BFIR, an egress autonomous system boundary router (ASBR), a multicast traffic packet forwarding system, a computer device, and a computer-readable storage medium.

Description

Multicast traffic message forwarding method and system, computer equipment and readable medium

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese patent application No. 202211197937.3 filed on September 29, 2022, the contents of which are incorporated herein by reference in their entirety.

Technical Field

The present disclosure relates to the field of computer technology, and in particular to a multicast traffic message forwarding method, a bit forwarding ingress router, an egress autonomous domain boundary router, a multicast traffic message forwarding system, a computer device, and a computer-readable storage medium.

Background technique

BIER (Bit Index Explicit Replication) technology greatly facilitates the deployment and application of multicast services because it does not require a special protocol to explicitly build a multicast distribution tree, nor does it require intermediate nodes to maintain the status of each multicast traffic. As IPv6 truly enters the implementation stage, major operators have proposed G-BIER (Generalized Bit Index Explicit Replication) technology based on the IPv6 data plane.

The relevant BIER protocol has good support for single autonomous system (AS) networks, but has many deficiencies in supporting cross-autonomous domain networks. In some cross-autonomous domain networks, the BIER information of devices within the autonomous domain needs to be announced in all other autonomous domains. The information within each autonomous domain cannot be kept private, and there is too much forwarding information to maintain. In some cross-autonomous domain networks, the autonomous system boundary router (ASBR) is required to first decapsulate the original multicast traffic message from the BIER message received from the upstream autonomous domain, and then re-capsulate the BIER header according to the downstream autonomous domain information, which reduces the traffic forwarding efficiency.

Public Content

On the one hand, an embodiment of the present disclosure provides a multicast traffic message forwarding method, which is applied to a bit forwarding inlet router (BFIR), including: receiving multicast traffic cross-autonomous domain (AS) forwarding information announced by a controller; carrying the multicast traffic cross-AS forwarding information in the traffic message to be forwarded to generate a first multicast traffic message, wherein the first multicast traffic message carries a basic header and an extended header, and the information carried in the extended header of the first multicast traffic message is obtained according to the multicast traffic cross-AS forwarding information; and determining the export autonomous domain boundary router (ASBR) within the AS to which the BFIR belongs according to the multicast traffic cross-AS forwarding information, and sending the first multicast traffic message to the export ASBR, so that the export ASBR generates a second multicast traffic message sent to the inlet ASBR of the downstream directly connected AS according to the first multicast traffic message and the extended header carried by it.

On the other hand, an embodiment of the present disclosure provides a multicast traffic message forwarding method, which is applied to an egress autonomous domain border router (ASBR), comprising: receiving a multicast traffic message sent by an ingress ASBR in an autonomous domain (AS) to which the egress ASBR belongs, wherein the multicast traffic message carries a basic header and an extended header, and when the ingress ASBR is a bit forwarding ingress router (BFIR) of a forwarding path, the multicast traffic message is a first multicast traffic message generated by the BFIR; when it is determined that the egress ASBR is an egress ASBR for forwarding the multicast traffic message based on the basic header carried by the multicast traffic message, a second multicast traffic message is generated based on the multicast traffic message and the extended header carried by the multicast traffic message; and determining the ingress ASBR of a downstream directly connected AS based on the extended header of the multicast traffic message, and sending the second multicast traffic message to the ingress ASBR of the downstream directly connected AS, so that the ingress ASBR of the downstream directly connected AS forwards the second multicast traffic message within its AS.

On the other hand, an embodiment of the present disclosure also provides a bit forwarding ingress router (BFIR) having at least one computer program stored thereon. When the at least one computer program is executed by the at least one processor, the at least one processor implements the above-mentioned multicast traffic message forwarding method applied to the BFIR.

On the other hand, an embodiment of the present disclosure also provides an egress autonomous domain border router (ASBR) having at least one computer program stored thereon. When the at least one computer program is executed by the at least one processor, the at least one processor implements the above-mentioned multicast traffic packet forwarding method applied to the egress ASBR.

On the other hand, an embodiment of the present disclosure also provides a multicast traffic packet forwarding system, comprising: a bit forwarding ingress router (BFIR), an egress autonomous domain boundary router (ASBR) and a controller; the BFIR is the BFIR described above; the egress ASBR is the egress ASBR described above; the controller is configured to notify the BFIR of multicast traffic cross-autonomous domain forwarding information.

On the other hand, an embodiment of the present disclosure also provides a computer device, comprising: at least one processor; and a storage device, on which at least one computer program is stored; when the at least one computer program is executed by the at least one processor, the at least one processor implements the multicast traffic packet forwarding method as described above.

On the other hand, an embodiment of the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed, the multicast traffic message forwarding method as described above is implemented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a network topology structure provided by an embodiment of the present disclosure;

FIG2 is a schematic diagram of a process of forwarding a multicast traffic message with a forwarding ingress router as the execution subject provided by an embodiment of the present disclosure;

FIG3 is a schematic diagram of the structure of a first multicast traffic message provided in an embodiment of the present disclosure;

4 is a schematic diagram of a process of forwarding multicast traffic packets with an autonomous domain border router as the execution subject provided by an embodiment of the present disclosure;

FIG5 is a schematic diagram of an extension head structure provided in an embodiment of the present disclosure;

FIG6 is a schematic diagram of a process of forwarding multicast traffic packets provided by an example of the present disclosure;

FIG7 is a schematic diagram of the structure of a first multicast traffic message provided by an example of the present disclosure;

8 to 10 are schematic diagrams of the structure of a second multicast traffic message provided by an example of the present disclosure; and

FIG11 is a schematic diagram of the structure of the Border Gateway Protocol-Link State Protocol provided in an embodiment of the present disclosure.

Detailed ways

The exemplary embodiments will be described more fully below with reference to the accompanying drawings, but the exemplary embodiments may be embodied in different forms, and the present disclosure should not be construed as being limited to the embodiments set forth herein. The purpose of providing these embodiments is to make the present disclosure more thorough and complete, and to enable those skilled in the art to fully understand the scope of the present disclosure.

As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The terms used herein are only used to describe specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will also be understood that when the terms "comprising" and/or "made of" are used in this specification, specific features, wholes, steps, operations, elements and/or components are specified, but the presence or addition of one or more other features, wholes, steps, operations, elements, components and/or groups thereof are not excluded.

The embodiments described herein may be described with reference to plan views and/or cross-sectional views by means of idealized schematic diagrams of the present disclosure. Therefore, the example illustrations may be modified according to manufacturing techniques and/or tolerances. Therefore, the embodiments are not limited to the embodiments shown in the drawings, but include modifications of the configurations formed based on the manufacturing process. Therefore, the regions illustrated in the drawings have schematic properties, and the shapes of the regions shown in the drawings illustrate the specific shapes of the regions of the elements, but are not restrictive.

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

The embodiment of the present disclosure provides a method for forwarding multicast traffic packets. FIG1 is a schematic diagram of the system architecture provided by the embodiment of the present disclosure. The system shown in FIG1 includes a controller, a BFIR (Bit Forwarding Ingress Router), a BFER (Bit Forwarding Egress Router), and an ASBR (Autonomous System Border Router). Multicast traffic packets are transmitted in each autonomous domain including AS100, AS200, AS300, AS400, AS500, and AS600. The original multicast traffic enters from the bit forwarding ingress router BFIR1 located in AS100, and the bit forwarding egress routers BFER2 to BFER14 are the receivers of the multicast traffic.

Each autonomous domain notifies the controller of routing basic layer information and BIER layer information through protocols such as BGP-LS (Border Gateway Protocol-Link State). Routing basic layer information includes the network topology information within the autonomous domain and the connection status with other autonomous domains. BIER layer information includes BFER, BFIR, BFR (Bit Forwarding Router) and G-BIER related information of ASBR, such as Sub-Domain (sd), Bit String Length (BSL), Set Identifier (SI), Bit Forwarding Router ID (BFR ID), Bit Forwarding Router Prefix (BFR-prefix), and Multicast Policy Reserved Address (MPRA).

The controller calculates the multicast forwarding path of multicast traffic from BFIR to each BFER based on the global topology information, generates the G-BIER basic header and BIER Bit-to-BitString Mapping extended header information required for forwarding multicast traffic across autonomous domains, and notifies the BFIR of this information. The BitString field in the G-BIER basic header only sets the BFR identifier of the BFER that belongs to the same autonomous domain as the BFIR and the ASBR of the autonomous domain that needs to pass through to other autonomous domains. The path information of the BFER that belongs to a different autonomous domain from the BFIR will be carried in the BIER Bit-to-BitString Mapping extended header information. The controller calculates the optimal multicast traffic forwarding path based on the topology information it has, as shown by the arrow in Figure 1. It generates the G-BIER basic header and BIER Bit-to-BitString Mapping extended header information and notifies it to the bit forwarding entry router BFIR1. The BitString field of the G-BIER basic header only sets the bits corresponding to the BFR identifiers of the bit forwarding egress routers BFER2, BFER3, autonomous domain boundary routers ASBR11 and autonomous domain boundary routers ASBR12 in the autonomous domain AS100. The BIER Bit-to-BitString Mapping extended header is used to instruct the ASBR how to continue forwarding multicast traffic to the downstream directly connected AS.

After receiving the original multicast traffic, the bit forwarding ingress router BFIR1 encapsulates the original multicast traffic according to the G-BIER basic header and BIER Bit-to-BitString Mapping extension header announced by the controller and forwards it in this autonomous domain.

After receiving the G-BIER multicast traffic message (i.e., encapsulated multicast traffic), autonomous domain border routers ASBR11 and autonomous domain border routers ASBR12 will find that their BFR identifier is set in the BitString field in the G-BIER basic header. In addition to sending the G-BIER multicast traffic message to the multicast layer, they also check the BIER Bit-to-BitString Mapping extension header. If the value of the Index Bit field found in the BIER Bit-to-BitString Mapping extension header is their own BFR identifier, the Next Hop MPRA field and the Mapping BitString field in the BIER Bit-to-BitString Mapping extension header are used to update the destination IP address in the G-BIER multicast traffic message and the value of the BitString field in the G-BIER basic header.

The embodiment of the present disclosure provides a multicast traffic packet forwarding method, which is applied to BFIR. As shown in FIG. 2 , the multicast traffic packet forwarding method includes steps S11 to S13.

Step S11: receiving multicast traffic inter-AS forwarding information notified by the controller.

The multicast traffic forwarding information across ASs is calculated by the controller based on the routing basic layer information and BIER layer information reported by each AS. The routing basic layer information includes the network topology information within the AS and the network topology information between each AS. In other words, the controller obtains the routing basic layer information and BIER layer information, as well as the source and receiver information of the multicast traffic from each AS, calculates the optimal multicast traffic forwarding path based on the topological information it has, generates the G-BIER basic header information and the BIER Bit-to-BitString Mapping extended header information, and notifies them to the BFIR.

Step S12, carrying the multicast traffic inter-AS forwarding information in the traffic message to be forwarded to generate a first multicast traffic message, wherein the first multicast traffic message carries a basic header and an extended header, and the information carried in the extended header of the first multicast traffic message is obtained according to the multicast traffic inter-AS forwarding information.

The BFIR receives the original multicast traffic, encapsulates the basic header and the extended header according to the G-BIER basic header information and the BIER Bit-to-BitString Mapping extended header information announced by the controller to generate a first multicast traffic message, and forwards the first multicast traffic message within the autonomous domain (for example, autonomous domain AS100).

Step S13, determining the egress ASBR in the AS to which the BFIR belongs according to the multicast traffic inter-AS forwarding information, and sending the first multicast traffic message to the egress ASBR, so that the egress ASBR generates a second multicast traffic message to be sent to the ingress ASBR of the downstream directly connected AS according to the first multicast traffic message and the extended header it carries.

The BFIR can determine the BFR identifier of the set egress ASBR in the AS where the BFIR is located based on the BitString field in the basic header of the first multicast traffic message, thereby determining the corresponding egress ASBRs. The BFIR sends the first multicast traffic message to the BFER and each egress ASBR in this AS, so that each egress ASBR generates a second multicast traffic message and sends the second multicast traffic message to the downstream directly connected AS.

The multicast traffic message forwarding method provided by the embodiment of the present disclosure is applied to the BFIR, including: receiving the multicast traffic cross-AS forwarding information notified by the controller; carrying the multicast traffic cross-AS forwarding information in the traffic message to be forwarded to generate a first multicast traffic message, wherein the first multicast traffic message carries a basic header and an extended header, and obtains the information carried in the extended header of the first multicast traffic message according to the multicast traffic cross-AS forwarding information; and determining the egress ASBR in the AS to which the BFIR belongs according to the multicast traffic cross-AS forwarding information, and sending the first multicast traffic message to the egress ASBR, so that the egress ASBR generates a second multicast traffic message to be sent to the ingress ASBR of the downstream directly connected AS according to the first multicast traffic message and the extended header carried by it. In the multicast traffic message forwarding method provided by the present invention, the routing base layer information and BIER information of each autonomous domain are reported to the controller, and the controller generates multicast traffic cross-AS forwarding information based on the routing base layer information and the BIER information and sends it to the BFIR. Each autonomous domain keeps its internal information private and independent, and there is no need for the autonomous domains to notify each other of BIER information, thereby reducing the BIER routing information and forwarding information that each autonomous domain needs to maintain.

As shown in Figure 3, the extended header carried by the first multicast traffic message includes a first field (Next Hop MPRA field), a second field (Mapping BitString field) and a third field (Index Bit field). The third field indicates the BFR identifier of the egress ASBR in the AS to which the BFIR belongs or the BFR identifier of the egress ASBR in the downstream AS of the AS to which the BFIR belongs. It can be recorded in binary code or in bit mark, and it is not mandatory.

The first field represents the address of the ingress ASBR of the downstream AS directly connected to the egress ASBR corresponding to the third field of the extended header where the first field is located; when the egress ASBR of the upstream AS forwards the G-BIER multicast traffic message to the downstream directly connected AS, it replaces the destination IP address in the IPv6 header of the G-BIER multicast traffic message with the first field.

The second field represents at least one of the BFR identifier of the egress ASBR in the downstream AS directly connected to the egress ASBR corresponding to the third field of the extended header where the second field is located and the BFR identifier of the BFER, that is, the bit of the BFR identifier. When the egress ASBR of the upstream AS forwards the G-BIER multicast traffic message to the downstream directly connected AS, it replaces the value of the BitString field in the G-BIER basic header with the value of the second field.

The extension header carried by the first multicast traffic message also includes a Type field and a Length field. The Type field indicates that the extension header is a BIER Bit-to-BitString Mapping extension header; the length counted by the Length field is not the length of a single BIER Bit-to-BitString Mapping extension header, but the total length of the BIER Bit-to-BitString Mapping extension header required to reach the downstream BFER with the ASBR indicated by the Index Bit field as the root.

In some implementations, as shown in FIG3 , the basic header carried by the first multicast traffic message includes a fourth field (BtoBS field) and a fifth field (BtoBS len field), the value of the fourth field indicates whether the first multicast traffic message carries an extension header, and the value of the fifth field indicates the number of extension headers carried by the first multicast traffic message. For example, if the BtoBS field is set to 1, it indicates that the first multicast traffic message carries an extension header, and if the BtoBS field is set to 0, it indicates that the first multicast traffic message does not carry an extension header.

The original G-BIER basic header has a 22-bit reserved field between the DSCP and BitString fields. To accommodate the BIER Bit-to-BitString Mapping extension header, the reserved field is divided into the BtoBS field and the BtoBS len field. In the disclosed embodiment, when the BtoBS field is set to 1, it indicates that there is a BIER Bit-to-BitString Mapping extension header after the G-BIER basic header. The G-BIER basic header can carry multiple BIER Bit-to-BitString Mapping extension headers. Each BIER Bit-to-BitString Mapping extension header corresponds to a cross-autonomous domain forwarding between an export ASBR and a downstream directly connected AS. The value of the BtoBS len field indicates the total number of all BIER Bit-to-BitString Mapping extension headers carried.

In some embodiments, the receiving controller notifies the multicast traffic cross-AS forwarding information (i.e., step S11) including the following steps: using one of the following to receive the multicast traffic cross-AS forwarding information notified by the controller: NETCONF protocol, BGP (Border Gateway Protocol), RESTCONF protocol, PCEP (Path Computation Unit Communication Protocol).

The embodiment of the present disclosure further provides a multicast traffic message forwarding method, which is applied to an egress ASBR, as shown in FIG. 4 , and includes steps S21 to S23 .

Step S21, receiving a multicast traffic message sent by an ingress ASBR in an AS to which the egress ASBR belongs, wherein the multicast traffic message carries a basic header and an extension header, and when the ingress ASBR is a BFIR of a forwarding path, the multicast traffic message is a first multicast traffic message generated by the BFIR.

Step S22: when the egress ASBR is determined as the egress ASBR for forwarding the multicast traffic message according to the basic header carried by the multicast traffic message, a second multicast traffic message is generated according to the multicast traffic message and the extended header carried by the multicast traffic message.

Step S23, determining the ingress ASBR of the downstream directly connected AS according to the extension header of the multicast traffic message, and sending the second multicast traffic message to the ingress ASBR of the downstream directly connected AS, so that the ingress ASBR of the downstream directly connected AS forwards the second multicast traffic message in its AS.

As shown in Figure 1, for the autonomous domain border router ASBR11 and the autonomous domain border router ASBR12, the multicast traffic message they receive is the first multicast traffic message generated by the inlet ASBR (i.e., the bit forwarding inlet router BFIR1) of the AS to which they belong (i.e., the autonomous domain AS100). For the autonomous domain border router ASBR11, a second multicast traffic message is further generated based on the first multicast traffic message and the extension header it carries, and the second multicast traffic message is sent to the inlet autonomous domain border routers ASBR21 and ASBR41 in the autonomous domains AS200 and AS400, respectively, so that the autonomous domain border routers ASBR21 and ASBR41 forward the second multicast traffic message in the autonomous domains AS200 and AS400, respectively. It should be noted that for the autonomous domain AS200, the multicast traffic message received by the autonomous domain border router ASBR22 and the autonomous domain border router ASBR23 is the second multicast traffic message generated by the inlet ASBR (i.e., the autonomous domain border router ASBR21) of the autonomous domain AS200.

The multicast traffic message forwarding method provided in the embodiment of the present disclosure is applied to the egress ASBR, including: receiving a multicast traffic message sent by an ingress ASBR in the AS to which the egress ASBR belongs, wherein the multicast traffic message carries a basic header and an extended header, and when the ingress ASBR is a BFIR of the forwarding path, the multicast traffic message is a first multicast traffic message generated by the BFIR; when the egress ASBR is determined as an egress ASBR for forwarding multicast traffic messages according to the basic header carried by the multicast traffic message, generating a second multicast traffic message according to the multicast traffic message and the extended header carried by it; and determining the ingress ASBR of the downstream directly connected AS according to the extended header of the multicast traffic message, and sending the second multicast traffic message to the ingress ASBR of the downstream directly connected AS, so that the ingress ASBR of the downstream directly connected AS forwards the second multicast traffic message within the AS to which it belongs. The multicast traffic message forwarding method provided in the present disclosure can generate a second multicast traffic message according to the multicast traffic message and its extended header information sent by the ingress ASBR of the AS to which the egress ASBR belongs, without the need to recalculate and encapsulate the BIER encapsulation header according to the downstream autonomous domain information. Improve the efficiency of multicast traffic forwarding and ensure that multicast traffic is sent in multicast form within an AS and between ASs, thereby reducing bandwidth usage.

In some embodiments, as shown in FIG. 5 , the extended header carried by the second multicast traffic message includes a first field (Next Hop MPRA field), a second field (Mapping BitString field), and a third field (Index Bit field), and the third field represents the BFR identifier of the egress ASBR in the AS to which the BFIR belongs or the BFR identifier of the egress ASBR in the downstream AS of the AS to which the BFIR belongs.

The method of generating a second multicast traffic message according to the multicast traffic message and the extended header carried by the multicast traffic message (i.e., step S22) includes the following steps: using the value of the first field of the target extended header as the destination address of the IPv6 message header of the second multicast traffic message, the first field representing the address of the ingress ASBR of the downstream AS directly connected to the egress ASBR corresponding to the third field of the target extended header where the first field is located; using the value of the second field of the target extended header as the value of the BitString field in the basic header of the second multicast traffic message, the second field representing at least one of the BFR identifier of the egress ASBR in the downstream AS directly connected to the egress ASBR corresponding to the third field of the target extended header where the second field is located and the BFR identifier of the BFER; the target extended header is an extended header in which the BFR identifier indicated by the third field of the extension header in the multicast traffic message is equal to the BFR identifier of the egress ASBR.

The second multicast traffic message may carry an extension header or may not carry an extension header. Whether the second multicast traffic message carries an extension header depends on the AS to which the second multicast traffic message belongs, the network topology structure, and the transmission path of the multicast traffic.

In some embodiments, the generating of the second multicast traffic message based on the multicast traffic message and the extended header carried by the multicast traffic message (i.e., step S22) includes the following steps: when the value of the length field of the target extension header is greater than 0, the second multicast traffic message carries m extension headers after the target extension header, where m is determined according to the value of the length field of the target extension header.

When the value of the length field of the target extension header is equal to 0, the second multicast traffic packet does not carry the extension header.

In some embodiments, when the value of the length field in the target extension header represents the number of extension headers, m is equal to the value of the length field in the target extension header; when the value of the length field in the target extension header represents the number of bytes occupied by the extension header, m is equal to the value of the length field in the target extension header divided by the length of a single extension header.

As shown in Figure 3, the basic header carried by the multicast traffic message includes the fourth field (BtoBS field) and the fifth field (BtoBS len field). The value of the fourth field indicates whether the second multicast traffic message carries an extension header. The value of the fifth field indicates the number of extension headers, and the value of the fifth field is determined according to the value of the length field in the target extension header.

In some implementations, determining the ingress ASBR of the downstream directly connected AS based on the extension header of the multicast traffic message (ie, step S23) includes the following steps: determining the ingress ASBR of the downstream directly connected AS based on the value of the first field in the extension header of the multicast traffic message.

FIG6 is a flow chart of multicast traffic message forwarding provided according to the example of the present disclosure. As shown in FIG6, when the egress ASBR receives a multicast traffic message with a BIER Bit-to-BitString Mapping extension header, the processing process of copying and forwarding the multicast traffic message to its downstream directly connected AS according to the information of the BIER Bit-to-BitString Mapping extension header is as follows: the egress ASBR detects that the BitString field in the G-BIER basic header encapsulated with the multicast traffic message includes a bit setting corresponding to its own BFR identifier. In addition to sending the multicast traffic message to the multicast layer, the BtoBS field and the BtoBS len field are also checked. If the value of the BtoBS field is 1 and the value of the BtoBS len field is greater than 0, it means that the G-BIER basic header carries at least one BIER Bit-to-BitString Mapping extension header. If the value of the BtoBS field is 0 and the value of the BtoBS len field is 0, it means that the multicast traffic message to be sent has no extension header, and the process ends; if the value of the BtoBS field is greater than 0 and the value of the BtoBS len field is greater than 0, an exception is handled. The egress ASBR checks the Index Bit field of each BIER Bit-to-BitString Mapping extension header in turn. If the value of the Index Bit field is equal to the BFR identifier of the egress ASBR, it means that the BIER Bit-to-BitString Mapping extension header is the target extension header. Then, a copy of the G-BIER multicast traffic message is copied to obtain the second multicast traffic message, which is sent to the ingress ASBR of the downstream directly connected AS indicated by the Next Hop MPRA field of the BIER Bit-to-BitString Mapping extension header. The G-BIER multicast traffic message (i.e., the second multicast traffic message) is generated in the following manner: the destination IP address of the IPv6 header is filled in with the value of the Next Hop MPRA field of the BIER Bit-to-BitString Mapping extension header, the BitString field of the G-BIER basic header is filled in with the value of the Mapping BitString field of the BIER Bit-to-BitString Mapping extension header, and the BtoBS len field in the G-BIER basic header is updated with the length field in the BIER Bit-to-BitString Mapping extension header. If the value of the length field in the BIER Bit-to-BitString Mapping extension header is greater than 0, a number of BIER Bit-to-BitString Mapping extension headers corresponding to the length of the value of the length field after the current BIER Bit-to-BitString Mapping extension header is copied to the G-BIER basic header as a new extension header, and the second multicast traffic message is sent to the ingress ASBR of the downstream directly connected AS indicated by the destination IP address. If the value of the length field in the BIER Bit-to-BitString Mapping extension header is 0, it means that the second multicast traffic packet does not carry the extension header, and the second multicast traffic packet is directly sent to the ingress ASBR of the downstream directly connected AS indicated by the destination IP.

To clearly illustrate the solution of the embodiment of the present disclosure, the multicast traffic message forwarding method of the embodiment of the present disclosure is described in detail below with reference to FIGS. 1 , 7 to 10 and specific examples.

Figure 7 is a structural diagram of the first multicast traffic message provided according to the example of the present disclosure. The bit forwarding inlet router BFIR1 encapsulates the first multicast traffic message with a BIER Bit-to-BitString Mapping extension header for cross-autonomous domain forwarding multicast traffic according to the information announced by the controller.

For ease of understanding, FIG7 omits fields such as the IPv6 header and the original multicast message in the multicast traffic, and only highlights the G-BIER basic header and the BIER Bit-to-BitString Mapping extension header. In order to correspond to the network topology shown in FIG1, the BitString field of the G-BIER basic header and the Mapping BitString field of the BIER Bit-to-BitString Mapping extension header use text to describe the bits that need to be set. In addition, the value of the length field in each extension header in FIG7 is the number of BIER Bit-to-BitString Mapping extension headers required by all downstream BFERs of the branch that reaches the egress ASBR indicated by the Index Bit field in the extension header as the root through the autonomous domain to which the node indicated by the Next Hop MPRA field belongs. It should be noted that if the value of the length field is expressed in bytes, the number of extension headers is multiplied by the length of the BIER Bit-to-BitString Mapping extension header corresponding to the specific BSL.

As shown in Figure 1 and Figure 7, the value of the BtoBS field in the G-BIER basic header is 1 and the value of the BtoBS len field is 5, indicating that the first multicast traffic message sent by the bit forwarding entry router BFIR1 carries 5 BIER Bit-to-BitString Mapping extension headers. The first three extension headers are used to indicate the arrival at the bit forwarding exit routers BFER4, BFER5, BFER6, BFER7, BFER13 and BFER14 nodes, autonomous domain border router ASBR11 to autonomous domain border router ASBR21, autonomous domain border router ASBR22 to autonomous domain border router ASBR31, autonomous domain border router ASBR23 to autonomous domain border router ASBR61 how to forward G-BIER multicast traffic packets. The subsequent two extension headers are used to instruct autonomous domain border router ASBR11 to autonomous domain border router ASBR41, autonomous domain border router ASBR12 to autonomous domain border router ASBR51 how to forward G-BIER multicast traffic packets.

The bits of the BFR identifiers of the bit forwarding exit routers BFER2, BFER3 and autonomous domain border router ASBR12 corresponding to the BitString field carried by the G-BIER basic header are cleared to 0 when they reach the autonomous domain border router ASBR11. The autonomous domain border router ASBR11 detects that its own BFR identifier is set in the BitString field, and checks that the value of the BtoBS field is set to 1 and the value of the BtoBS len field is greater than 0. Then, the autonomous domain border router ASBR11 searches for the extension header corresponding to its own BFR identifier in the Index Bit field in the BIER Bit-to-BitString Mapping extension header carried by the first multicast traffic message. According to the first multicast traffic message format shown in Figure 7, the autonomous domain border router ASBR11 finds that the Index Bit field value of the first BIER Bit-to-BitString Mapping extension header is equal to its own BFR identifier, then the autonomous domain border router ASBR11 copies a G-BIER encapsulated multicast traffic message, and uses the "ASBR21's MPRA address" in the Next Hop MPRA field in the first BIER Bit-to-BitString Mapping extension header to fill in the destination IP address part of the IPv6 message header, and uses the "BitString set BFER4, BFER5, ASBR22 and ASBR23's BFR id" in the Mapping BitString field in the first BIER Bit-to-BitString Mapping extension header to fill in the BitString field in the G-BIER basic header. Because the value of the length field of the first Bit-to-BitString Mapping extension header is 2 (i.e., greater than 0), the autonomous domain border router ASBR11 uses the value of the length field in the first BIER Bit-to-BitString Mapping extension header (len=2) to update the value of the BtoBS len field in the G-BIER basic header of the second multicast traffic message. The autonomous domain border router ASBR11 also needs to copy the subsequent two BIER Bit-to-BitString Mapping extension headers of the extension header currently being processed to the G-BIER basic header of the second multicast traffic message, thereby generating the second multicast traffic message sent to the autonomous domain border router ASBR21. The format of the second multicast traffic message sent by the autonomous domain border router ASBR11 to the autonomous domain border router ASBR21 is shown in Figure 8.

ASBR11 continues to check the BIER Bit-to-BitString Mapping extension header and finds that the value of the Index Bit field of the fourth extension header is also equal to the BFR identifier of ASBR11. ASBR11 copies another G-BIER encapsulated multicast traffic message and fills in the destination IP address part of the IPv6 message header with the "MPRA address of ASBR41" in the Next Hop MPRA field of the fourth BIER Bit-to-BitString Mapping extension header, and fills in the BitString field in the G-BIER basic header with the "BFR id of BFER8 and BFER9 set to BitString" in the Mapping BitString field of the fourth BIER Bit-to-BitString Mapping extension header. Because the value of the length field of the fourth BIER Bit-to-BitString Mapping extension header is equal to 0, the newly generated second multicast traffic message sent to ASBR41 does not need to carry the BIER Bit-to-BitString Mapping extension header. The format of the second multicast traffic message sent by the autonomous domain border router ASBR11 to the autonomous domain border router ASBR41 is shown in FIG9 .

Similarly, the format of the second multicast traffic message sent by the autonomous domain border router ASBR12 to the autonomous domain border router ASBR51 is shown in FIG. 10 .

Each autonomous domain can notify the controller of the routing base layer information and BIER layer information through the BGP-LS protocol. The BGP-LS protocol format is shown in Figure 11. It should be noted that the disclosed embodiment does not limit the protocol used by each autonomous domain to notify the controller of the routing base layer information and BIER layer information. As long as the extended information can indicate the node information of the source of the specified multicast traffic and the autonomous domain in which it is located, and the node information of the receiver and the autonomous domain in which it is located, the controller can calculate the multicast distribution tree with the source as the root and the receiver as the leaf based on this extended information, and generate the G-BIER extension header and BIER Bit-to-BitString Mapping extension header information required for cross-autonomous domain forwarding for BFIR. It does not enforce the specification.

In order to solve the problem of insufficient support for cross-autonomous domain network situations, the disclosed embodiment provides a multicast traffic forwarding solution implemented in a G-BIER layered manner within and between autonomous domains, while maintaining the privacy and independence of each autonomous domain information. The disclosed embodiment adds a BIER extension header BIER Bit-to-BitString Mapping, which instructs the ASBR how to forward multicast traffic to its downstream autonomous domain and update the BitString field suitable for the next autonomous domain by carrying at least one BIER Bit-to-BitString Mapping extension header in the original BIER header of the multicast traffic message.

By adopting the multicast traffic message forwarding method described in the embodiment of the present invention, each autonomous domain keeps its internal information private and independent, and there is no need for the autonomous domains to notify each other of BIER information, thereby reducing the BIER routing information and forwarding information that each autonomous domain needs to maintain. The ASBR does not need to receive the BIER multicast traffic message, parse the original multicast message, and then recalculate the BIER encapsulation header. The multicast traffic message forwarding method provided by the present invention can ensure that multicast traffic is sent as multicast within and between autonomous domains, thereby reducing bandwidth occupancy.

The embodiment of the present disclosure also provides a bit forwarding ingress router BFIR, on which at least one computer program is stored. When the at least one computer program is executed by the at least one processor, the at least one processor implements the multicast traffic message forwarding method applied to the BFIR as described above.

The embodiment of the present disclosure also provides an export autonomous domain border router ASBR, on which at least one computer program is stored. When the at least one computer program is executed by the at least one processor, the at least one processor implements the multicast traffic message forwarding method applied to the export ASBR as described above.

The disclosed embodiment also provides a multicast traffic message forwarding system, comprising: a BFIR, an egress ASBR and a controller; the BFIR is the BFIR described above; the egress ASBR is the egress ASBR described above; the controller is configured to notify the BFIR of multicast traffic cross-autonomous domain forwarding information.

The embodiment of the present disclosure also provides a computer device, including: at least one processor and a storage device; at least one computer program is stored on the storage device, and when the at least one computer program is executed by the at least one processor, the at least one processor implements the multicast traffic message forwarding method as described above.

The embodiment of the present disclosure further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the multicast traffic message forwarding method as described above is implemented.

Those skilled in the art will appreciate that all or some of the steps, systems, and functional modules/units in the above disclosed methods may be implemented as software, firmware, Hardware and appropriate combinations thereof. In hardware implementations, the division between the functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some physical components or all physical components may be implemented as software executed by a processor (such as a central processing unit, a digital signal processor, or a microprocessor), or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Example embodiments have been disclosed herein, and although specific terms are employed, they are used and should be interpreted only in a general illustrative sense and not for limiting purposes. In some instances, it will be apparent to those skilled in the art that, unless otherwise expressly noted, features, characteristics, and/or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and/or elements described in conjunction with other embodiments. Therefore, those skilled in the art will appreciate that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims (17)

A multicast traffic message forwarding method, applied to a bit forwarding inlet router BFIR, comprising: Receive multicast traffic forwarding information across autonomous domains AS announced by the controller; Carrying the multicast traffic inter-AS forwarding information in a traffic message to be forwarded to generate a first multicast traffic message, wherein the first multicast traffic message carries a basic header and an extended header, and obtaining information carried in an extended header of the first multicast traffic message according to the multicast traffic inter-AS forwarding information; and Determine the exit autonomous domain border router ASBR within the AS to which the BFIR belongs based on the multicast traffic cross-AS forwarding information, and send the first multicast traffic message to the exit ASBR so that the exit ASBR can generate a second multicast traffic message to be sent to the entry ASBR of the downstream directly connected AS based on the first multicast traffic message and the extension header it carries. The method according to claim 1, wherein the extension header carried by the first multicast traffic message includes a first field, a second field, and a third field, and the third field represents a bit forwarding router BFR identifier of an export ASBR in the AS to which the BFIR belongs or a BFR identifier of an export ASBR in a downstream AS of the AS to which the BFIR belongs; The first field indicates an address of an ingress ASBR of a downstream AS directly connected to the egress ASBR corresponding to the third field of the extension header where the first field is located; The second field indicates at least one of a BFR identifier of an egress ASBR in a downstream AS directly connected to the egress ASBR corresponding to the third field of the extension header where the second field is located and a BFR identifier of a bit forwarding egress router BFER. The method as claimed in claim 1, wherein the basic header carried by the first multicast traffic message includes a fourth field and a fifth field, the value of the fourth field indicates whether the first multicast traffic message carries an extension header, and the value of the fifth field indicates the number of extension headers carried by the first multicast traffic message. As described in the method of claim 1, wherein the multicast traffic cross-AS forwarding information is calculated by the controller based on the routing base layer information and bit index explicit replication BIER layer information reported by each AS, and the routing base layer information includes the network topology information within the AS and the network topology information between ASs. The method according to claim 1, wherein the multicast traffic cross-autonomous domain AS forwarding information announced by the receiving controller includes: Use one of the following to forward multicast traffic across ASs announced by the receiving controller: NETCONF, Border Gateway Protocol (BGP), RESTCONF, or PCEP. A multicast traffic message forwarding method, which is applied to an export autonomous domain border router (ASBR), comprises: receiving a multicast traffic message sent by an ingress ASBR in the autonomous domain AS to which the egress ASBR belongs, wherein the multicast traffic message carries a basic header and an extended header, and when the ingress ASBR is a bit forwarding ingress router BFIR of a forwarding path, the multicast traffic message is a first multicast traffic message generated by the BFIR; In a case where the egress ASBR is determined as the egress ASBR for forwarding the multicast traffic message according to the basic header carried by the multicast traffic message, generating a second multicast traffic message according to the multicast traffic message and the extended header carried by the multicast traffic message; and The ingress ASBR of the downstream directly connected AS is determined according to the extended header of the multicast traffic message, and the second multicast traffic message is sent to the ingress ASBR of the downstream directly connected AS, so that the ingress ASBR of the downstream directly connected AS forwards the second multicast traffic message within its AS. The method according to claim 6, wherein the extension header carried by the second multicast traffic message includes a first field, a second field, and a third field, and the third field represents a bit forwarding router BFR identifier of an export ASBR in the AS to which the BFIR belongs or a BFR identifier of an export ASBR in the downstream AS of the AS to which the BFIR belongs; the generating a second multicast traffic message according to the multicast traffic message and the extension header carried by the message includes: Using the value of the first field of the target extension header as the destination address of the IPv6 header of the second multicast traffic packet, the first field representing the address of the ingress ASBR of the downstream AS directly connected to the egress ASBR corresponding to the third field of the target extension header where the first field is located; The value of the second field of the target extension header is used as the value of the BitString field in the basic header of the second multicast traffic message, where the second field represents at least one of a BFR identifier of an egress ASBR in a downstream AS directly connected to the egress ASBR corresponding to the third field of the target extension header where the second field is located and a BFR identifier of a bit forwarding egress router BFER; The target extended header is an extended header in which the BFR identifier indicated by the third field of the extended header in the multicast traffic message is equal to the BFR identifier of the egress ASBR. The method according to claim 7, wherein generating a second multicast traffic message according to the multicast traffic message and the extended header carried by the multicast traffic message comprises: When the value of the length field of the target extension header is greater than 0, the second multicast traffic message carries m extension headers after the target extension header, where m is determined according to the value of the length field of the target extension header. The method of claim 8, wherein, in the case where the value of the length field in the target extension header indicates the number of extension headers, the m is equal to the value of the length field in the target extension header; In the case where the value of the length field in the target extension header represents the number of bytes occupied by the extension header, m is equal to the value of the length field in the target extension header divided by the length of a single extension header. The method according to claim 7, wherein generating a second multicast traffic message according to the multicast traffic message and the extended header carried by the multicast traffic message comprises: When the value of the length field of the target extension header is equal to 0, the second multicast traffic packet does not carry the extension header. The method as claimed in claim 7, wherein the basic header carried by the multicast traffic message includes a fourth field and a fifth field, the value of the fourth field indicates whether the second multicast traffic message carries an extension header, the value of the fifth field indicates the number of extension headers, and the value of the fifth field is determined according to the value of the length field in the target extension header. The method according to any one of claims 6 to 11, wherein the determining the ingress ASBR of the downstream directly connected AS according to the extension header of the multicast traffic message comprises: The ingress ASBR of the downstream directly connected AS is determined according to the value of the first field in the extended header of the multicast traffic message. A bit forwarding ingress router (BFIR) having at least one computer program stored thereon, wherein when the at least one computer program is executed by the at least one processor, the at least one processor implements the multicast traffic message forwarding method as described in any one of claims 1 to 5. An export autonomous domain border router ASBR has at least one computer program stored thereon, and when the at least one computer program is executed by the at least one processor, the at least one processor implements the multicast traffic message forwarding method as described in any one of claims 6 to 12. A multicast traffic message forwarding system comprises: a bit forwarding inlet router BFIR, an export autonomous domain boundary router ASBR and a controller; wherein, The BFIR is the BFIR according to claim 13; The outlet ASBR is the outlet ASBR according to claim 14; The controller is configured to notify the BFIR of multicast traffic cross-autonomous domain forwarding information. A computer device comprising: at least one processor; and a storage device having at least one computer program stored thereon; When the at least one computer program is executed by the at least one processor, the at least one processor implements the multicast traffic message forwarding method according to any one of claims 1 to 12. A computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, the multicast traffic message forwarding method according to any one of claims 1 to 12 is implemented.