A packet processing method, a network node, and a system includes obtaining, by a first network node, a first packet that includes a segment list, where the segment list includes a segment identifier of a network node on a path used to forward the first packet, obtaining, by the first network node, a segment identifier of a second network node from the segment list, where the second network node is a next-hop segment node of the first network node on the path, replacing, by the first network node, a destination address of the first packet with the segment identifier of the second network node, and adding a network performance parameter of the first network node to the segment list to generate a second packet, and sending, by the first network node, the second packet to the second network node.

A packet processing method, a network node, and a system includes obtaining, by a first network node, a first packet that includes a segment list, where the segment list includes a segment identifier of a network node on a path used to forward the first packet, obtaining, by the first network node, a segment identifier of a second network node from the segment list, where the second network node is a next-hop segment node of the first network node on the path, replacing, by the first network node, a destination address of the first packet with the segment identifier of the second network node, and adding a network performance parameter of the first network node to the segment list to generate a second packet, and sending, by the first network node, the second packet to the second network node.

A data transmission method, a node, and a system, the method including receiving, by a forwarding node, a data packet, where a label stack of the data packet comprises a path identifier (path-ID), where the path-ID is an identifier of a constrained path, and where the constrained path is a path that consists of at least two nodes arranged in a specific order, determining, by the forwarding node, that the forwarding node is a node on the constrained path, selecting, by the forwarding node, a target label/target address from a local available label block/address block according to the path-ID and according to a preset rule, where the label block/address block comprises at least one label/address, searching for, by the forwarding node, a corresponding target interface according to the target label/target address, and forwarding, by the forwarding node, the data packet through the target interface.

A data transmission method, a node, and a system, the method including receiving, by a forwarding node, a data packet, where a label stack of the data packet comprises a path identifier (path-ID), where the path-ID is an identifier of a constrained path, and where the constrained path is a path that consists of at least two nodes arranged in a specific order, determining, by the forwarding node, that the forwarding node is a node on the constrained path, selecting, by the forwarding node, a target label/target address from a local available label block/address block according to the path-ID and according to a preset rule, where the label block/address block comprises at least one label/address, searching for, by the forwarding node, a corresponding target interface according to the target label/target address, and forwarding, by the forwarding node, the data packet through the target interface.

A system and method are disclosed for enabling interoperability between asymmetric and symmetric Integrated Routing and Bridging (IRB) modes. A system is configured to receive a route advertisement, examine the label fields of the route advertisement, and determine whether Layer 2 or Layer 3 information is conveyed. The system is further configured to build a route advertisement to advertise to a second device based on whether Layer 2 or Layer 3 information is conveyed in the first route advertisement.

A packet loss processing method and a network device are provided. The method includes: A first node obtains a first forwarding label of a first packet, where the first packet is a discarded packet. The first node determines, based on the first forwarding label, that the first node does not have a LSP corresponding to the first forwarding label. The first node sends a first message to a second node, where the first message includes the first forwarding label, and the first message is used to indicate that the first node does not have the LSP corresponding to the first forwarding label. The second node may be, for example, a peer node of the first node. The first node sends the message to the peer node, to indicate that the first node does not have the LSP corresponding to the forwarding label.

A packet loss processing method and a network device are provided. The method includes: A first node obtains a first forwarding label of a first packet, where the first packet is a discarded packet. The first node determines, based on the first forwarding label, that the first node does not have a LSP corresponding to the first forwarding label. The first node sends a first message to a second node, where the first message includes the first forwarding label, and the first message is used to indicate that the first node does not have the LSP corresponding to the first forwarding label. The second node may be, for example, a peer node of the first node. The first node sends the message to the peer node, to indicate that the first node does not have the LSP corresponding to the forwarding label.

In one embodiment, a segment routing and tunnel exchange provides packet forwarding efficiencies in a network, including providing an exchange between a segment routing domain and a packet tunnel domain. One application includes the segment routing and tunnel exchange interfacing segment routing packet forwarding (e.g., in a Evolved Packet Core (EPC) and/or 5-G user plane) and packet tunnel forwarding in access networks (e.g., replacing a portion of a tunnel between an access node and a user plane function for accessing a corresponding data network). In one embodiment, a network provides mobility services using a segment routing data plane that spans segment routing and tunnel exchange(s) and segment routing-enabled user plane functions. One embodiment uses the segment routing data plane without any modification to a (radio) access network (R)AN (e.g., Evolved NodeB, Next Generation NodeB) nor to user equipment (e.g., any end user device).

In one embodiment, a segment routing and tunnel exchange provides packet forwarding efficiencies in a network, including providing an exchange between a segment routing domain and a packet tunnel domain. One application includes the segment routing and tunnel exchange interfacing segment routing packet forwarding (e.g., in a Evolved Packet Core (EPC) and/or 5-G user plane) and packet tunnel forwarding in access networks (e.g., replacing a portion of a tunnel between an access node and a user plane function for accessing a corresponding data network). In one embodiment, a network provides mobility services using a segment routing data plane that spans segment routing and tunnel exchange(s) and segment routing-enabled user plane functions. One embodiment uses the segment routing data plane without any modification to a (radio) access network (R)AN (e.g., Evolved NodeB, Next Generation NodeB) nor to user equipment (e.g., any end user device).

The present disclosure provides a method and device for forwarding a priority tag across network segments. The method includes the following steps: performing networking by using a Virtual Local Area Network (VLAN) interface to form a network; enabling a VLAN Class Of Service (COS) and differentiated service code point in a priority tag of a message transmitted in the network to correspond to each other; in response to layer-3 forwarding of the message, using the differentiated service code point priority tag for the message, and copying a VLAN COS value of the message at an entry of a switch to a VLAN COS value of the message at an exit; and in response to subsequent layer-2 forwarding of the message, using the VLAN COS priority tag for the message to distinguish a priority of the message.