Bier packet forwarding method, device, and system

1 . A bit index explicit replication (BIER) packet forwarding method, wherein the method comprises:

receiving, by a first network device, a BIER packet sent by a second network device, wherein the BIER packet comprises an internet protocol version 6 (IPv6) header, a bit index explicit replication (BIER) header, and a multicast packet, wherein a destination address of the IPv6 header carries a service identifier, and the service identifier identifies a virtual private network (VPN) instance, wherein the service identifier is carried in a part of bits of the destination address of the IPv6 header, and the destination address indicates to perform BIER forwarding on the BIER packet, and wherein the part of bits of the destination address is an argument part of the destination address;

determining, by the first network device, a virtual route forwarding (VRF) table based on the service identifier and a first correspondence, wherein the first correspondence is between the service identifier and the VRF table; and

sending, by the first network device, the multicast packet to a first customer edge (CE) device in the VRF table based on the VRF table.

2 . The method according to claim 1 , further comprising:

receiving, by the first network device, a control packet, wherein the control packet comprises the first correspondence between the service identifier and the VRF table; and

storing, by the first network device, the first correspondence between the service identifier and the VRF table.

3 . The method according to claim 1 , wherein the first correspondence further comprises a source address; and

wherein determining, by the first network device, the virtual route forwarding (VRF) table based on the service identifier and the first correspondence comprises:

determining, by the first network device, the VRF table based on the source address of the IPv6 header, the service identifier, and the first correspondence.

4 . The method according to claim 1 , wherein the first network device is a bit forwarding egress router (BFER).

5 . The method according to claim 1 , wherein a locator field and a function field of the destination address indicate a BIER forwarding operation.

6 . A bit index explicit replication (BIER) packet forwarding method, the method comprising:

obtaining, by a second network device, a multicast packet;

encapsulating, by the second network device, the multicast packet based on a virtual private network (VPN) instance to which the multicast packet belongs, to obtain a BIER packet, wherein the BIER packet comprises an internet protocol version 6 (IPv6) header, a bit index explicit replication (BIER) header, and the multicast packet, and wherein a destination address of the IPv6 header carries a service identifier, and the service identifier identifies the VPN instance, and wherein the service identifier is carried in a part of bits of the destination address of the IPv6 header, and the destination address indicates to perform BIER forwarding on the BIER packet, and wherein the part of bits of the destination address is an argument part of the destination address; and

sending, by the second network device, the BIER packet to a first network device.

7 . The method according to claim 6 , further comprising:

allocating, by the second network device, the service identifier to the VPN instance; and

establishing, by the second network device, a first correspondence, wherein the first correspondence is between the service identifier and a virtual route forwarding (VRF) table corresponding to the VPN instance.

8 . The method according to claim 7 , further comprising:

sending, by the second network device, a control packet to the first network device, wherein the control packet comprises the first correspondence between the service identifier and the VRF table.

9 . The method according to claim 8 , wherein the control packet is a border gateway protocol (BGP) packet.

10 . The method according to claim 6 , wherein the first network device is a bit forwarding egress router (BFER).

11 . The method according to claim 6 , wherein a locator field and a function field of the destination address indicate a BIER forwarding operation.

12 . A first network device, comprising:

a non-transitory memory storing instructions; and

at least one processor coupled to the non-transitory memory;

wherein the instructions, when executed by the at least one processor, cause the first network device to be configured to:

receive a bit index explicit replication (BIER) packet sent by a second network device, wherein the BIER packet comprises an internet protocol version 6 (IPv6) header, a bit index explicit replication (BIER) header, and a multicast packet, wherein a destination address of the IPv6 header carries a service identifier, and the service identifier identifies a virtual private network (VPN) instance, and wherein the service identifier is carried in a part of bits of the destination address of the IPv6 header, and the destination address indicates to perform BIER forwarding on the BIER packet, and wherein the part of bits of the destination address is an argument part of the destination address;

determine a virtual route forwarding (VRF) table based on the service identifier and a first correspondence, wherein the first correspondence is between the service identifier and the VRF table; and

send the multicast packet to a first customer edge (CE) device in the VRF table based on the VRF table.

13 . The first network device according to claim 12 , wherein the instructions, when executed by the processor, further cause the first network device to be configured to:

receive a control packet, wherein the control packet comprises the first correspondence between the service identifier and the VRF table; and

store the first correspondence between the service identifier and the VRF table.

14 . The first network device according to claim 12 , wherein the first correspondence further comprises a source address; and the instructions, when executed by the processor, further cause the first network device to be configured to:

determine the VRF table based on the source address of the IPv6 header, the service identifier, and the first correspondence.

15 . The first network device according to claim 12 , wherein the first network device is a bit forwarding egress router (BFER).

16 . A second network device, comprising:

a non-transitory memory storing instructions; and

at least one processor coupled to the non-transitory memory; wherein the instructions, when executed by the at least one processor, cause the second network device to be configured to:

obtain a multicast packet;

encapsulate the multicast packet based on a virtual private network (VPN) instance to which the multicast packet belongs, to obtain a bit index explicit replication (BIER) packet, wherein the BIER packet comprises an internet protocol version 6 (IPv6) header, a bit index explicit replication (BIER) header, and the multicast packet, wherein a destination address of the IPv6 header carries a service identifier, and the service identifier identifies the VPN instance, and wherein the service identifier is carried in a part of bits of the destination address of the IPv6 header, and the destination address indicates to perform BIER forwarding on the BIER packet, and wherein the part of bits of the destination address is an argument part of the destination address; and

send the BIER packet to a first network device.

17 . The second network device according to claim 16 , wherein the instructions, when executed by the at least one processor, further cause the first network device to be configured to:

allocate the service identifier to the VPN instance; and

establish a first correspondence between the service identifier and a virtual route forwarding (VRF) table corresponding to the VPN instance.

18 . The second network device according to claim 17 , wherein the instructions, when executed by the at least one processor, further cause the first network device to be configured to:

send a control packet to the first network device, wherein the control packet comprises the correspondence between the service identifier and the VRF table.

19 . The second network device according to claim 18 , wherein the control packet is a border gateway protocol (BGP) packet.

20 . The second network device according to claim 16 , wherein the first network device is a bit forwarding egress router (BFER).