The disclosure describes techniques for enhancements to the Multicast Source Discovery Protocol (MSDP) to reduce Source Active (SA) message loops in one or more multicast domains having overlapping MSDP mesh groups. In some examples, a method includes receiving, by a first MSDP speaker, from a second MSDP speaker, a SA message. The method also includes, when the second MSDP speaker is in a mesh group with the first MSDP speaker, determining whether the first MSDP speaker includes an active SA state corresponding to the SA message. Additionally, the method includes, when the first MSDP speaker does not include the active SA state corresponding to the SA message, accepting the SA message and forwarding the SA message to a third MSDP speaker that is not in the mesh group with the first MSDP speaker and the second MSDP speaker.

The disclosure describes techniques for enhancements to the Multicast Source Discovery Protocol (MSDP) to reduce Source Active (SA) message loops in one or more multicast domains having overlapping MSDP mesh groups. In some examples, a method includes receiving, by a first MSDP speaker, from a second MSDP speaker, a SA message. The method also includes, when the second MSDP speaker is in a mesh group with the first MSDP speaker, determining whether the first MSDP speaker includes an active SA state corresponding to the SA message. Additionally, the method includes, when the first MSDP speaker does not include the active SA state corresponding to the SA message, accepting the SA message and forwarding the SA message to a third MSDP speaker that is not in the mesh group with the first MSDP speaker and the second MSDP speaker.

A communications method includes determining, by a first platoon member, at least one second platoon member, where the first platoon member and the at least one second platoon member belong to a same platoon, and signal quality of a communication link from the first platoon member to each second platoon member is less than a first preset quality threshold, determining, by the first platoon member, a target communications node, where signal quality of a communication link from the target communications node to each second platoon member is greater than or equal to the first preset quality threshold, and sending, by the first platoon member, to-be-sent data to each second platoon member through the target communications node.

The present disclosure describes methods, system, and devices for selecting a radio bearer mode for multicast broadcast services (MBS). The method includes informing a radio access network (RAN) that a user equipment (UE) is receiving/interested to receive or no longer receiving/interested to receive multicast broadcast service (MBS) services via a cast mode. The method includes sending, by the UE, MBS interest information to the RAN, the MBS interest information comprising a list of MBS services of interest.

The present disclosure describes methods, system, and devices for selecting a radio bearer mode for multicast broadcast services (MBS). The method includes informing a radio access network (RAN) that a user equipment (UE) is receiving/interested to receive or no longer receiving/interested to receive multicast broadcast service (MBS) services via a cast mode. The method includes sending, by the UE, MBS interest information to the RAN, the MBS interest information comprising a list of MBS services of interest.

A method and apparatus for selective connection establishment for a broadcast-multicast service in a wireless communication system is provided. A wireless device receives bandwidth information for a broadcast-multicast service. A wireless device determines whether a connection to receive the broadcast-multicast service is required or not, based on the bandwidth information. A wireless device receives the broadcast-multicast service based on the determination.

A method and apparatus for selective connection establishment for a broadcast-multicast service in a wireless communication system is provided. A wireless device receives bandwidth information for a broadcast-multicast service. A wireless device determines whether a connection to receive the broadcast-multicast service is required or not, based on the bandwidth information. A wireless device receives the broadcast-multicast service based on the determination.

Data retransmission method is disclosed. The method includes: obtaining a mapping relationship between GTP-U sequence numbers of N data packets sent by a source node and source PDCP sequence numbers assigned to the N data packets by the source node; and performing data retransmission based on the mapping relationship.

This application discloses a multicast transmission method. The multicast transmission method includes: a first network device receives a first data packet and first indication information, where the first indication information indicates a sequence of the first data packet in at least one data packet; the first network device sets a sequence number of a first protocol layer of the first data packet based on the first indication information; and the first network device sends the first data packet to a terminal device. In this way, all data packets received by the terminal device include corresponding sequence numbers of the first protocol layers.

This application discloses a multicast transmission method. The multicast transmission method includes: a first network device receives a first data packet and first indication information, where the first indication information indicates a sequence of the first data packet in at least one data packet; the first network device sets a sequence number of a first protocol layer of the first data packet based on the first indication information; and the first network device sends the first data packet to a terminal device. In this way, all data packets received by the terminal device include corresponding sequence numbers of the first protocol layers.