Multicast Forwarding Method and Apparatus

#The present disclosure relates to communications technologies, and in particular, to a multicast forwarding method, a bit-forwarding egress router (BFER), a bit-forwarding ingress router (BFIR), and a registration router.

#A bit index explicit replication (BIER) technology is a novel packet transmission technology. In the BIER technology, a packet may be transmitted using multiple bit-forwarding routers (BFR) disposed in a BIER network.

#Both a BFIR and a BFER are BFRs in the BIER network. The BFIR may send a packet to the BFER in the BIER network. The BFIR may obtain a bit string according to a bit corresponding to the BFER, and the bit, in the bit string, corresponding to the BFER is set. The BFIR may add the bit string to the packet to obtain a BIER packet. In this way, a BFR that receives the BIER packet may forward the BIER packet to the BFER according to the bit that is set in the bit string.

#To describe the technical solutions in the embodiments of the present disclosure more clearly, the following briefly describes the accompanying drawings required for describing the embodiments. The accompanying drawings in the following description show merely some embodiments of the present disclosure, and persons of ordinary skill may still derive other drawings from these accompanying drawings.

#FIG. 1A is a flowchart of a multicast forwarding method according to an embodiment of the present disclosure;

#FIG. 1B is a flowchart of a multicast forwarding method according to an embodiment of the present disclosure;

#To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the following clearly describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. The described embodiments are some rather than all of the embodiments of the present disclosure. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present disclosure shall fall within the protection scope of the present disclosure.

#The embodiments of the present disclosure provide a multicast forwarding method. In the method, a BFER in a BIER network may determine, according to information that is about a multicast group in a multicast receiver list and that is obtained in advance, an IP address of a registration router that supports the multicast group, where the registration router has a capability of processing a multicast registration message. The BFER generates a BFER registration message according to the information about the multicast group and the IP address of the registration router that supports the multicast group, where the registration router has a capability of processing the multicast registration message, the multicast registration message includes the BFER registration message, the BFER registration message includes the information about the multicast group, a destination IP address of the BFER registration message is the IP address of the registration router, and a source IP address of the BFER registration message is an IP address of the BFER, and the BFER sends the BFER registration message to the registration router. After receiving the BFER registration message sent by the BFER, the registration router in the BIER network may obtain a BFER entry according to the BFER registration message, where the BFER entry includes the information about the multicast group and the IP address of the BFER, and the IP address of the BFER corresponds to the information about the multicast group.

#In the method and the apparatus that are provided in the embodiments of the present disclosure, if the registration router may be used as a BFIR, the registration router may generate a BIER multicast packet according to one or more obtained BFER entries and a received multicast packet, and the registration router used as a BFIR may send the BIER multicast packet in the BIER network. If a router used as a BFIR is not the registration router, the router used as a BFIR may request the IP address of the BFER from the registration router, the router used as a BFIR may generate a BIER multicast packet according to the IP address of the BFER and a received multicast packet, and the router used as a BFIR may send the BIER multicast packet in the BIER network.