Abstract: A packet processing method and system, and a network device are disclosed, and belong to the field of network technologies. A first network device sends a first packet to a second network device through a first tunnel, and sends a second packet to a third network device through a second tunnel. The second network device forwards the first packet to the third network device through a third tunnel. The third network device processes the first packet and the second packet. The first network device is located at a first site. The second network device and the third network device are located at a second site. The first site and the second site are connected through a wide area network. Wide area network multipath transmission may be implemented in a multi-gateway scenario.

Abstract: A method, a device, and a system for transmitting a multicast packet are provided. The method includes: when a device that is in a source subnet and that is connected to a core network receives a multicast packet of a target multicast group, determining addresses of devices that are in a plurality of destination subnets corresponding to the target multicast group and that are connected to the core network, replicating the multicast packet, to obtain a plurality of multicast packets whose quantity is equal to a quantity of the plurality of destination subnets, separately adding outer encapsulation to each multicast packet, and forwarding the multicast packet to which the outer encapsulation is added, where a destination address in the outer encapsulation is an address of a device that is in each destination subnet and that is connected to the core network.

Abstract: A multicast data transmission method includes: determining, by a first BFIR in a first BIER domain, a BIFT-id and a bitstring that correspond to multicast data in a second BIER domain, where the BIFT-id is determined based on at least an SI to which a BFR-id of a first BFER belongs and a BSL supported by the first BFER, and the first BFER is a BFER in the second BFER domain that is used to receive the multicast data; encapsulating the multicast data into a BIER data packet, where a BIER header of the BIER data packet includes the BIFT-id and the bitstring that correspond to the multicast data in the second BIER domain; and finally sending the labeled BIER data packet to a second BFIR, where the label is a label corresponding to a prefix of the second BFIR.

Abstract: This application discloses a network congestion control method and a network device, and relates to the field of communication technologies, to improve continuity and completion of a packet in a transmission process of a Transmission Control Protocol (TCP) flow. In this application, when pre-congestion (that is, congestion may occur) occurs in a forwarding direction of the TCP flow, a forwarding device reduces a value of a receive window (RWND) field in an acknowledge (ACK) packet, to reduce a sending rate of a transmit end for a packet in the TCP flow or delay sending of a packet by a transmit end. This relieves buffer pressure of the forwarding device, reduces a packet loss, and improves the continuity and the completion of the packet in the transmission process of the TCP flow.

Abstract: A data multicast implementation method, apparatus, and system are provided. In some embodiments, a transmission device receives a standby forwarding path establishment request, where the standby forwarding path establishment request includes a device identifier, has a destination address being an address of a multicast source device, and is used to request to establish a standby forwarding path between a multicast destination device identified by the device identifier and the multicast source device. In those embodiments, when determining, based on the device identifier in the standby forwarding path establishment request, that the transmission device is located on an active forwarding path between the multicast destination device and the multicast source device, the transmission device skips using the transmission device as a device on the standby forwarding path between the multicast destination device and the multicast source device, and skips forwarding the standby forwarding path establishment request.

Abstract: A method for measuring available bandwidth includes a transmit end that sends a first probe sequence to a receive end, and receives a first available bandwidth measurement result from the receive end, the transmit end determines a second probe sequence based on the first available bandwidth measurement result, where the second probe sequence includes a group of probe packets with increasing sending rates, a range of the sending rates of the second probe sequence is the same as a range of the sending rates of the first probe sequence, the transmit end sends the second probe sequence to the receive end, and receives the second available bandwidth measurement result from the receive end, and the transmit end obtains the available bandwidth based on the second available bandwidth measurement result.

Abstract: A flow control method and system, and a device are provided to implement flow control in a process of transmitting a media stream between devices. The method includes: receiving, by a first device, a media stream that is sent by a second device at a first rate; instructing based on a rate of a media stream in a first time period in which a buffer usage rises from a first threshold to a second threshold, the second device to send a media stream to the first device at a second rate which is less than the first rate; instructing based on a rate of a media stream in a second time period in which the buffer usage rises from the second threshold to a third threshold, the second device to send a media stream to the first device at a third rate which is not greater than the second rate.

Abstract: A method for measuring available bandwidth includes a transmit end that sends a first probe sequence to a receive end, and receives a first available bandwidth measurement result from the receive end, the transmit end determines a second probe sequence based on the first available bandwidth measurement result, where the second probe sequence includes a group of probe packets with increasing sending rates, a range of the sending rates of the second probe sequence is the same as a range of the sending rates of the first probe sequence, the transmit end sends the second probe sequence to the receive end, and receives the second available bandwidth measurement result from the receive end, and the transmit end obtains the available bandwidth based on the second available bandwidth measurement result.

Abstract: A data multicast implementation method, apparatus, and system are provided. In some embodiments, a transmission device receives a standby forwarding path establishment request, where the standby forwarding path establishment request includes a device identifier, has a destination address being an address of a multicast source device, and is used to request to establish a standby forwarding path between a multicast destination device identified by the device identifier and the multicast source device. In those embodiments, when determining, based on the device identifier in the standby forwarding path establishment request, that the transmission device is located on an active forwarding path between the multicast destination device and the multicast source device, the transmission device skips using the transmission device as a device on the standby forwarding path between the multicast destination device and the multicast source device, and skips forwarding the standby forwarding path establishment request.

Abstract: A multicast data transmission method includes: determining, by a first BFIR in a first BIER domain, a BIFT-id and a bitstring that correspond to multicast data in a second BIER domain, where the BIFT-id is determined based on at least an SI to which a BFR-id of a first BFER belongs and a BSL supported by the first BFER, and the first BFER is a BFER in the second BFER domain that is used to receive the multicast data; encapsulating the multicast data into a BIER data packet, where a BIER header of the BIER data packet includes the BIFT-id and the bitstring that correspond to the multicast data in the second BIER domain; and finally sending the labeled BIER data packet to a second BFIR, where the label is a label corresponding to a prefix of the second BFIR.

Abstract: A method, a device, and a system for transmitting a multicast packet are provided. The method includes: when a device that is in a source subnet and that is connected to a core network receives a multicast packet of a target multicast group, determining addresses of devices that are in a plurality of destination subnets corresponding to the target multicast group and that are connected to the core network, replicating the multicast packet, to obtain a plurality of multicast packets whose quantity is equal to a quantity of the plurality of destination subnets, separately adding outer encapsulation to each multicast packet, and forwarding the multicast packet to which the outer encapsulation is added, where a destination address in the outer encapsulation is an address of a device that is in each destination subnet and that is connected to the core network.

Abstract: A flow control method and system, and a device are provided to implement flow control in a process of transmitting a media stream between devices. The method includes: receiving, by a first device, a media stream that is sent by a second device at a first rate; instructing based on a rate of a media stream in a first time period in which a buffer usage rises from a first threshold to a second threshold, the second device to send a media stream to the first device at a second rate which is less than the first rate; instructing based on a rate of a media stream in a second time period in which the buffer usage rises from the second threshold to a third threshold, the second device to send a media stream to the first device at a third rate which is not greater than the second rate.