Embodiments of this application provide a packet transmission method, a communication apparatus, and a communication system. A target transport layer proxy network element establishes a fourth transport layer connection based on a first context of a source transport layer proxy network element, where the first context is a context about packet transmission of the source transport layer proxy network element on a first path. If the target transport layer proxy network element receives first indication information, and the first indication information indicates that application context migration between a first application server and a second application server is completed, the target transport layer proxy network element performs transport layer processing on a packet on a second path based on a second context of the target transport layer proxy network element, and transmits, on the second path, a packet obtained through the transport layer processing. Hence, a packet loss can be avoided.

Methods for wireless communication, a terminal device, and a network device are provided. The method includes: receiving, by the terminal device, a first message transmitted by a network device, where the first message includes a cause parameter; and ignoring or skip using, by the terminal device, a route selection descriptor (RSD) unsatisfying a cause-parameter condition according to the cause parameter.

In accordance with an embodiment, a packet transmission method includes receiving, by a second provider edge (PE) through a multicast tunnel, a bit indexed explicit replication (BIER) packet sent by a first PE, wherein the BIER packet comprises a bit string, and the bit string indicates a customer edge (CE) designated to receive the BIER packet; and processing, by the second PE based on the bit string, the BIER packet.

In accordance with an embodiment, a packet transmission method includes receiving, by a second provider edge (PE) through a multicast tunnel, a bit indexed explicit replication (BIER) packet sent by a first PE, wherein the BIER packet comprises a bit string, and the bit string indicates a customer edge (CE) designated to receive the BIER packet; and processing, by the second PE based on the bit string, the BIER packet.

A routing system for implementing a service and topology exchange protocol (STEP) includes a primary STEP server configured to maintain a STEP repository and a plurality of routers, with each router including a STEP client in communication with the primary STEP server. The STEP client of each router is configured to transmit, using STEP, STEP documents containing service and topology state information for at least one route or service available through the router to the primary STEP server for storage in the STEP repository. The primary STEP server is configured to transmit to the STEP client of each router, using STEP, service and topology state information from the STEP repository for at least one other router based on configured relationships between routers. Each router is configured to make routing decisions based at least in part on the service and topology state information from the at least one other router.

A method for distributing an optimal path to a router using a route reflector, that includes obtaining, by the route reflector, a path location bitmask associated with the optimal path, obtaining a router location bitmask associated with the router, performing a bitwise AND operation on the path location bitmask and the router location bitmask to obtain a result bitmask, identifying a nonzero bit in the result bitmask, and in response to identifying the nonzero bit, sending the optimal path to the router.

The disclosure describes techniques for concurrently operating multiple network stacks, one operating natively and one operating remotely, to control the routing table within a router of a network. An example network device includes a control unit comprising one or more processors. A native routing stack executes on the control unit to exchange routing protocol advertisements with a peer network device in accordance with a routing protocol. The native routing stack is configured to insert first routing entries into a routing table. The first routing entries are based on the routing protocol advertisements. A controller interface executed by the control unit receives second routing entries from a network controller and inserts the second routing entries into the routing table. A routing process generates a forwarding table based on the first and second routing entries.

The disclosure describes techniques for concurrently operating multiple network stacks, one operating natively and one operating remotely, to control the routing table within a router of a network. An example network device includes a control unit comprising one or more processors. A native routing stack executes on the control unit to exchange routing protocol advertisements with a peer network device in accordance with a routing protocol. The native routing stack is configured to insert first routing entries into a routing table. The first routing entries are based on the routing protocol advertisements. A controller interface executed by the control unit receives second routing entries from a network controller and inserts the second routing entries into the routing table. A routing process generates a forwarding table based on the first and second routing entries.

A health check is generated for at least two member paths between the local SDWAN controller and a remote SDWAN controller, with a set health check probe packets for transmission by the network interface to remote SDWAN controllers. A link cost is determined for each member path from a set of health check response packets received by the network interface. SDWAN network traffic is prioritized for each member path between the local SDWAN controller and the remote SDWAN controller based at least in part on the link cost.

A packet processing method includes a first network device receiving a first Bit Index Explicit Replication (BIER) packet including a first BIER header. When the first BIER packet is a packet sent to a second network device, and in response to determining that the second network device is an edge node device in a BIER communication network and does not support BIER packet forwarding, the first network device determines a target label used for a reverse path forwarding (RPF) check, updates the first BIER packet to obtain a second BIER packet, where the second BIER packet includes the target label but does not include the first BIER header, and sends the second BIER packet to the second network device.