A packet forwarding method and apparatus are provided, and pertain to the field of communications technologies. The method includes: determining, by a first node, information about a loop-free path from the first node to a second node, where the first node and the second node are a pair of nodes having an anycast route; and when the first node receives a packet to be sent to a third node, if a link from the first node to the third node is faulty, forwarding, by the first node, the packet to the second node based on the information about the loop-free path, so as to forward the packet to the third node through the second node. According to this application, a success rate of packet sending can be improved.

A packet sending method and device. The first node sets a next-hop of the routing information to a next-hop through which the first node reaches the first route source. The destination address of the routing information is the address prefix. When the second route source is superior to the first route source, the first node switches the next-hop of the routing information to a next-hop through which the first node reaches the second route source. Then, the first node adds, to a target packet, path information of a forwarding path from the first node to the second route source according to the switching operation, where a destination address of the target packet matches the address prefix. Finally, the first node forwards the target packet to the second route source through the forwarding path.

A system and method for identifying packets in a that may be stuck in a loop includes logically organizing the network as a tree and modifying packets with an artifice to identify the packets intended directionality within the tree. If the actual directionality conflicts with the intended directionality, a potential loop is indicated. The artifice is a flag in the link header, link address, or IP address associated with the packet.

The techniques disclosed herein enable systems to perform ordered reconvergence operations following a change to a topology of a communications network. To perform ordered reconvergence, a system detects a change to network topology such as a link failure or node addition. In response, the system determines a global delay based on a maximum distance between two nodes within the network, a local delay for each node within the network, and an ordered delay for each node based on the global delay and the local delay. Upon detecting that the ordered delay for a node has elapsed, the system can then update a routing table for the node. After updating routing tables for every node, the system can route data in the changed network topology using the updated routing tables.

A packet sending method and device. The first node sets a next-hop of the routing information to a next-hop through which the first node reaches the first route source. The destination address of the routing information is the address prefix. When the second route source is superior to the first route source, the first node switches the next-hop of the routing information to a next-hop through which the first node reaches the second route source. Then, the first node adds, to a target packet, path information of a forwarding path from the first node to the second route source according to the switching operation, where a destination address of the target packet matches the address prefix. Finally, the first node forwards the target packet to the second route source through the forwarding path.

An object is to provide a route switching method, a transfer device, and communication system that can continue communication even during route switching work. In a route switching method according to the present invention, in bypass transfer that transfers a packet while bypassing a non-transferable route, the transfer device having detected the non-transferable route attaches a bypass packet flag to the packet that passes through a non-transferable route and specifies the packet as a bypass packet, the transfer device having detected the non-transferable route returns the bypass packet and transfers the bypass packet in a direction opposite to that of the packet in the ring network, and the transfer device for which the blocked port is set in the ring network transfers the bypass packet through the blocked port before the route switching work.

The present invention provides a loop detection method applicable to a mesh network including a plurality of links among a plurality of devices, including: creating a neighbor graph based on a topology maintenance message, wherein the neighbor graph represents a network structure of the mesh network; traversing the neighbor graph; and detecting whether there is a loop existing in the mesh network according to a result from traversing the neighbor graph.

A loop prevention system includes a plurality of networking devices that are coupled together to form a Layer Two (L2) domain and at least a portion of the plurality of networking devices are coupled together in a physical loop configuration. A networking device included in the plurality of networking devices may include at least one L2 domain connection that couples the networking device to at least one of the plurality of networking devices in the L2 domain, and an edge connection that connects the networking device to a computing device that is outside of the L2 domain. The networking device may receive a data frame via the edge connection. The networking device then generates a loop breaker data frame by tagging the data frame with a loop breaker tag and forwards the loop breaker data frame via the at least one L2 domain connection.

A loop prevention system includes a plurality of networking devices that are coupled together to form a Layer Two (L2) domain and at least a portion of the plurality of networking devices are coupled together in a physical loop configuration. A networking device included in the plurality of networking devices may include at least one L2 domain connection that couples the networking device to at least one of the plurality of networking devices in the L2 domain, and an edge connection that connects the networking device to a computing device that is outside of the L2 domain. The networking device may receive a data frame via the edge connection. The networking device then generates a loop breaker data frame by tagging the data frame with a loop breaker tag and forwards the loop breaker data frame via the at least one L2 domain connection.

Various systems and methods for performing bit indexed explicit replication (BIER). For example, one method involves receiving a packet at a node. The packet includes a multicast forwarding entry. The multicast forwarding entry has a plurality of elements, and each element corresponds to a particular node. The method also involves comparing the multicast forwarding entry with forwarding information stored by the node. The method involves selecting a neighbor node based on the comparing, updating the multicast forwarding entry in the packet, and forwarding the packet to the neighbor node.