Bit index explicit replication (BIER) penultimate hop popping

1. A network device, comprising:

one or more memories; and

one or more processors to:

receive, from a first neighbor network device, information indicating that the network device is to remove a bit indexed explicit replication (BIER) header from a multicast packet prior to transmitting the multicast packet to the first neighbor network device;

receive, after receiving the information from the first neighbor network device, the multicast packet from a second neighbor network device,

wherein the multicast packet includes the BIER header and is to be transmitted to the first neighbor network device, and

wherein the network device, the first neighbor network device, and the second neighbor network device are included in a same BIER domain;

remove the BIER header from the multicast packet based on the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device; and

transmit the multicast packet to the first neighbor network device, after removing the BIER header from the multicast packet, by using at least one of a multiprotocol label switching (MPLS) label associated with the first neighbor network device or an address associated with the first neighbor network device,

wherein the multicast packet includes the at least one of the MPLS label or the address.

2. The network device of claim 1 , wherein the first neighbor network device is at least one of:

a BIER egress device, or

an egress device that does not support BIER.

3. The network device of claim 1 , wherein the network device is a BIER forwarding device, and

wherein the second neighbor network device is at least one of:

another BIER forwarding device, or

a BIER ingress device.

4. The network device of claim 1 , wherein the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device comprises:

a label indicating removal of the BIER header from the multicast packet.

5. The network device of claim 1 , wherein the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device is included in type field of a sub-type-length-value (sub-TLV) field included in a signaling packet,

wherein the type field of the sub-TLV field is associated with removal of the BIER header.

6. The network device of claim 1 , wherein the BIER header before being removed from the multicast packet, MPLS encapsulated.

7. The network device of claim 1 , wherein the multicast packet includes:

a BIER label for a MPLS-based BIER implementation, or

a bit index forwarding table (BIFT) identifier for a non-MPLS-based BIER implementation; and

wherein the one or more processors, when removing the BIER header from the multicast packet, are to:

remove the BIER label or the BIFT identifier from the multicast packet.

8. A non-transitory computer-readable medium storing instructions, the instructions comprising:

one or more instructions that, when executed by one or more processors of a network device, cause the one or more processors to:

receive, from a first neighbor network device, information indicating that the network device is to remove a bit indexed explicit replication (BIER) header from a multicast packet prior to transmitting the multicast packet to the first neighbor network device,

wherein the first neighbor network device does not support BIER;

receive, after receiving the information from the first neighbor network device, the multicast packet from a second neighbor network device,

wherein the multicast packet includes the BIER header and is to be transmitted to the first neighbor network device, and

wherein the network device, the first neighbor network device, and the second neighbor network device are included in a same BIER domain;

remove the BIER header from the multicast packet based on the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device; and

transmit the multicast packet to the first neighbor network device, after removing the BIER header from the multicast packet, by using at least one of a multiprotocol label switching (MPLS) label associated with the first neighbor network device or an address associated with the first neighbor network device,

wherein the multicast packet includes the at least one of the MPLS label or the address.

9. The non-transitory computer-readable medium of claim 8 , wherein the BIER header, before being removed from the multicast packet, is non-MPLS encapsulated.

10. The non-transitory computer-readable medium of claim 8 , wherein the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device is included in a type field of a sub-type-length-value (sub-TLV) field included in a signaling packet,

wherein the type field of the sub-TLV field is associated with removal of the BIER header.

11. The non-transitory computer-readable medium of claim 8 , wherein the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device comprises:

a label indicating removal of the BIER header included in the multicast packet.

12. The non-transitory computer-readable medium of claim 8 , wherein the second neighbor network device is at least one of:

a BIER ingress device, or

another BIER forwarding device.

13. The non-transitory computer-readable medium of claim 8 , wherein the network device is a BIER forwarding device.

14. The non-transitory computer-readable medium of claim 8 , wherein the multicast packet includes:

a BIER label for a MPLS-based BIER implementation, or

a bit index forwarding table (BIFT) identifier for a non-MPLS-based BIER implementation; and

wherein the one or more instructions, that cause the one or more processors to remove the BIER header from the multicast packet, cause the one or more processors to:

remove the BIER label or the BIFT identifier from the multicast packet.

15. A method, comprising:

receiving, at a network device and from a first neighbor network device, information indicating that the network device is to remove a bit indexed explicit replication (BIER) header from a multicast packet prior to transmitting the multicast packet to the first neighbor network device,

wherein the network device is a BIER forwarding device, and

wherein the first neighbor network device does not support BIER;

receiving, at the network device and after receiving the information from the first neighbor network device, the multicast packet from a second neighbor network device,

wherein the multicast packet includes the BIER header and is to be transmitted to the first neighbor network device,

wherein the network device, the first neighbor network device, and the second neighbor network device are included in a same BIER domain, and

wherein the second neighbor network device is at least one of:

another BIER forwarding device, or

a BIER ingress device;

removing, by the network device, the BIER header from the multicast packet based on the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device; and

transmitting, by the network device, the multicast packet to the first neighbor network device, after removing the BIER header from the multicast packet, by using at least one of a multiprotocol label switching (MPLS) label associated with the first neighbor network device or an address associated with the first neighbor network device,

wherein the multicast packet includes the at least one of the MPLS label or the address.

16. The method of claim 15 , wherein the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device is included in a value field of a sub-type-length-value (sub-TLV) field included in a signaling packet.

17. The method of claim 16 , wherein the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device comprises:

a type field, associated with removing the BIER header from the multicast packet, of another sub-TLV field included in the value field of the sub-TLV field.

18. The method of claim 15 , wherein the information indicating that the network device is to remove the BIER header from the multicast packet prior to transmitting the multicast packet to the first neighbor network device comprises:

a label indicating removal of the BIER header included in the multicast packet.

19. The method of claim 15 , wherein the network device, the first neighbor network device, and the second neighbor network device are included in at least one of:

a multicast virtual private network (MVPN), or

an Ethernet virtual private network (EVPN).

20. The method of claim 15 , wherein the multicast packet includes:

a BIER label for a MPLS-based BIER implementation, or

a bit index forwarding table (BIFT) identifier for a non-MPLS-based BIER implementation; and

wherein removing the BIER header from the multicast packet comprises:

removing the BIER label or the BIFT identifier from the multicast packet.