Abstract: A fault detection method, a network device, and a system are provided. The method includes: After a first network device receives, through a first forwarding path in an SR policy, a BFD packet that is sent by a second network device and that includes indication information of a SID list, the first network device determines, based on the indication information of the SID list, a second forwarding path that is reversely co-routed with the first forwarding path, and sends a response packet of the BFD packet to the second network device through the second forwarding path, so that the second network device can perform fault detection on the first forwarding path based on the response packet.

Abstract: A network system includes a first network device, a second network device, and a third network device. The first network device is configured to: obtain a first route advertisement message, where the first route advertisement message includes a first route prefix; and obtain a second route prefix based on the first route prefix, where the second route prefix corresponds to a first network slice, and the second route prefix is a subnet prefix of the first route prefix. The first network device advertises a second route advertisement message to the second network device, where the second route advertisement message includes the second route prefix.

Abstract: A packet sending method and a related device are disclosed. The method includes: A network device obtains a first packet, where an internet protocol extension header of the first packet includes a first identifier, and the first identifier indicates a service requirement corresponding to the first packet. The network device determines, based on the first identifier and a second identifier, path indication information corresponding to the first packet, where a destination address of the first packet includes the second identifier, and the path indication information herein includes one or more of a network slice identifier and a segment identifier list. The network device updates the first packet based on the path indication information to obtain a second packet, and sends the second packet.

Abstract: A method for advertising a processing capability of a network device, a system, and a network device are disclosed, and relate to the field of communication technologies. The method is performed by a network device, and includes: generating a advertisement message including indication information, where the indication information is used to indicate a processing capability of the network device, the processing capability of the network device includes a processing capability of ignoring secondary path information included in a packet when the network device serves as a network device on a primary path for forwarding the packet and receives the packet including primary path information and the secondary path information, and the secondary path information is used to indicate one or more secondary paths for forwarding the packet when the primary path is unavailable.

Abstract: A packet forwarding method, a system, an apparatus, and a network device are provided. The method is performed by a network device, and includes: obtaining first identification information of a first network resource required for forwarding first traffic to which a first packet belongs; determining a target port set based on the first identification information and a destination address of the first packet, where the target port set is associated with the first network resource; and selecting a first port from the target port set to forward the first packet.

Abstract: A packet sending method and apparatus, a network device, a system, and a storage medium are disclosed in the field of communication technologies. An edge network device of a tier-1 carrier that has upgraded to an SRv6 network establishes a mapping relationship between a segment identifier and an MPLS label. After receiving a packet that carries an MPLS label and that is sent by a network device of a tier-2 carrier, the edge network device generates, based on the mapping relationship, a packet carrying a segment identifier. The packet carrying the segment identifier is forwarded in the SRv6 network of the tier-1 carrier.

Abstract: Embodiments of this application disclose a method for verifying an SRv6 packet. An egress node of an IPsec tunnel may receive an SRv6 packet, where the SRv6 packet is a packet encapsulated in an IPsec transport mode. The SRv6 packet includes an AH and at least one SRH. The SRv6 packet carries first indication information, where the first indication information indicates the egress node to perform AH verification on the SRv6 packet. A verification range of the AH verification includes the at least one SRH.

Abstract: Embodiments of this application disclose a packet sending method, a device, and a system, so that a specified network device does not use a backup forwarding path to forward a packet, thereby reducing, to some extent, a technical problem such as network resource waste or network congestion caused by a loop problem. The method includes: A first network device obtains a first packet destined for a destination device; the first network device adds a first indication identifier to the first packet to generate a second packet, where the first indication identifier is used to indicate a second network device to avoid using a backup forwarding path from the second network device to the destination device to send the second packet to the destination device; and the first network device sends the second packet to the second network device by using a first forwarding path.

Abstract: A packet forwarding method is disclosed. The method includes: After an edge node in a trusted domain receives an SRv6 packet whose destination address is a BSID, the edge node may verify the packet based on a BSID in the packet and a destination field in an SRH of the packet. If the packet passes the verification, the edge node forwards the packet. If the packet fails the verification, the edge node discards the packet. Not only a node outside the trusted domain is required to access the trusted domain by using the BSID, but also the packet entering the trusted domain needs to be verified with reference to the target field in the segment routing header.

Abstract: The application discloses a packet transmission method, an apparatus, and a network device. In an embodiment, a first network device obtains identification information corresponding to a service flow, and reserves a forwarding resource based on the identification information. The forwarding resource is used by the first network device to forward the service flow to a second network device. The first network device further sends a packet including the identification information to the second network device, and the second network device reserves a corresponding forwarding resource based on the identification information in the packet. Network devices perform resource reservation hop by hop by sending the packet including the identification information, and do not need to perform resource reservation based on a transmission path that is pre-calculated and planned, so that load of the network device or a controller is reduced, and resource reservation flexibility is improved.

Abstract: A method includes: When receiving at least one policy, a first network device sends one or more policies in the at least one policy to a second network device based on filtering information. The filtering information includes a policy address family identifier and a device identifier of the second network device.

Abstract: An identifier can indicate whether local protection is allowed is added to a packet. In a process in which a packet that carries a protection flag is transmitted along a primary path, if a node along the path determines that the primary path is faulty, but the protection flag indicates that local switching to a protection path is not allowed, the node along the path does not perform local protection, so that the packet is not switched by the node along the path to the protection path. This prevents the packet from passing through a protection path with the node along the path as an ingress when the primary path is faulty, helps traffic on the primary path to be switched to an end-to-end protection path in time, and helps a packet sending side to switch the traffic on the primary path to the end-to-end protection path in time.

Abstract: A packet processing method includes a first network device receiving a first packet, where the first packet includes a plurality of segment identifier (SID) lists, the plurality of SID lists include a primary SID list and at least one secondary SID list. The at least one secondary SID list includes a first secondary SID list, and the first secondary SID list is a backup of the primary SID list. The first network device processes the first packet based on the primary SID list. When a forwarding path indicated by a segment identifier list is faulty, data packet forwarding processing can still be implemented in the segment routing network.

Abstract: A method for processing a packet on an SR network is provided, including: receiving a packet, where a packet header of the packet includes a destination address field, a first pointer, a second pointer, and a list used to process the packet, the list includes a plurality of sequentially arranged identifiers, and a value of the first pointer and a value of the second pointer jointly indicate a location of a first identifier in the plurality of identifiers in the list; determining the first identifier based on the value of the first pointer and the value of the second pointer; and copying the first identifier to the destination address field. In this method, a CL pointer is set in the packet header to jointly form a two-dimensional pointer with an SL pointer, to indicate a location of a C-SID in a SID list.