Abstract: A bit index explicit replication (BIER) packet sending method includes receiving, by a first node in a first BIER domain, a packet from a second node in a second BIER domain, where the packet carries an identifier of the second BIER domain, determining a BIER packet sending policy corresponding to the identifier of the second BIER domain based on the identifier of the second BIER domain and according to a preconfigured BIER packet sending policy, and encapsulating and sending a BIER packet according to the BIER packet sending policy.

Abstract: A bit index explicit replication (BIER) forwarding entry construction method is provided. The method includes receiving, by a second network device, a first message sent by a first network device, where the first message includes a host routing prefix of the first network device, first BIER information, and second BIER information. The first BIER information includes a bit index forwarding table identifier (BIFT ID) of the first network device, the second BIER information includes a bit forwarding router identifier (BFR ID) of at least one bit forwarding router (BFR) in a first area. The second network device constructs a BIER forwarding entry based on the first BIER information, the second BIER information, and the host routing prefix.

Abstract: A method, a device, and a system for transmitting a multicast packet are provided. The method includes: when a device that is in a source subnet and that is connected to a core network receives a multicast packet of a target multicast group, determining addresses of devices that are in a plurality of destination subnets corresponding to the target multicast group and that are connected to the core network, replicating the multicast packet, to obtain a plurality of multicast packets whose quantity is equal to a quantity of the plurality of destination subnets, separately adding outer encapsulation to each multicast packet, and forwarding the multicast packet to which the outer encapsulation is added, where a destination address in the outer encapsulation is an address of a device that is in each destination subnet and that is connected to the core network.

Abstract: A method for detecting a multicast service flow includes receiving, by a first node, a multicast service flow from a multicast source; encapsulating, by the first node, an In-situ Flow Information Telemetry (IFIT) extension header into a data packet in the multicast service flow, where the IFIT extension header includes a first detection identifier, and the first detection identifier is used to identify the detected multicast service flow; copying, by the first node according to a quantity of next-hop second nodes of the first node, the data packet encapsulated with the IFIT extension header; and sending, by the first node to each next-hop second node, the data packet encapsulated with the IFIT extension header. The first node is a head node in a multicast detection domain.

Abstract: A multicast data transmission method includes: determining, by a first BFIR in a first BIER domain, a BIFT-id and a bitstring that correspond to multicast data in a second BIER domain, where the BIFT-id is determined based on at least an SI to which a BFR-id of a first BFER belongs and a BSL supported by the first BFER, and the first BFER is a BFER in the second BFER domain that is used to receive the multicast data; encapsulating the multicast data into a BIER data packet, where a BIER header of the BIER data packet includes the BIFT-id and the bitstring that correspond to the multicast data in the second BIER domain; and finally sending the labeled BIER data packet to a second BFIR, where the label is a label corresponding to a prefix of the second BFIR.

Abstract: This application provides a service chain fault protection method, an apparatus, a device, a service chain fault protection system, and a storage medium, and relates to the field of communications technologies. In this application, in an SRV6 static service chain scenario, when a link between an SF network element and an SFF accessed by the SF network element is faulty, a secondary SID is introduced to update a destination address field of a packet header of a packet to the secondary SID, so that the packet is bypassed, based on the secondary SID, to another SFF accessed by the SF network element, thereby implementing fault protection in the link between the SFF and the SF network element.

Abstract: A bit index explicit replication (BIER) forwarding entry construction method is provided. The method includes receiving, by a second network device, a first message sent by a first network device, where the first message includes a host routing prefix of the first network device, first BIER information, and second BIER information. The first BIER information includes a bit index forwarding table identifier (BIFT ID) of the first network device, the second BIER information includes a bit forwarding router identifier (BFR ID) of at least one bit forwarding router (BFR) in a first area. The second network device constructs a BIER forwarding entry based on the first BIER information, the second BIER information, and the host routing prefix.

Abstract: A method and apparatus for implementing multicast. When a multicast source performs route advertisement, route update is performed on a cross-DC integrated device, and a received device identifier and a received AS number are replaced with a device identifier and an AS number that are of the integrated device. In this way, when a multicast user joins the multicast source, each network device in the network can trace the multicast source based on a received route, and determine a multicast path that is from the multicast source to the multicast user. Therefore, it is possible to accurately perform, in a NG MVPN, cross- DC multicast on traffic of the multicast source.

Abstract: A bit index explicit replication (BIER) packet sending method includes receiving, by a first node in a first BIER domain, a packet from a second node in a second BIER domain, where the packet carries an identifier of the second BIER domain, determining a BIER packet sending policy corresponding to the identifier of the second BIER domain based on the identifier of the second BIER domain and according to a preconfigured BIER packet sending policy, and encapsulating and sending a BIER packet according to the BIER packet sending policy.

Abstract: A multicast data transmission method includes: determining, by a first BFIR in a first BIER domain, a BIFT-id and a bitstring that correspond to multicast data in a second BIER domain, where the BIFT-id is determined based on at least an SI to which a BFR-id of a first BFER belongs and a BSL supported by the first BFER, and the first BFER is a BFER in the second BFER domain that is used to receive the multicast data; encapsulating the multicast data into a BIER data packet, where a BIER header of the BIER data packet includes the BIFT-id and the bitstring that correspond to the multicast data in the second BIER domain; and finally sending the labeled BIER data packet to a second BFIR, where the label is a label corresponding to a prefix of the second BFIR.

Abstract: A method, a device, and a system for transmitting a multicast packet are provided. The method includes: when a device that is in a source subnet and that is connected to a core network receives a multicast packet of a target multicast group, determining addresses of devices that are in a plurality of destination subnets corresponding to the target multicast group and that are connected to the core network, replicating the multicast packet, to obtain a plurality of multicast packets whose quantity is equal to a quantity of the plurality of destination subnets, separately adding outer encapsulation to each multicast packet, and forwarding the multicast packet to which the outer encapsulation is added, where a destination address in the outer encapsulation is an address of a device that is in each destination subnet and that is connected to the core network.