Forwarding multicast data packets using bit index explicit replication (BIER) for BIER-incapable network devices

1. A network device, comprising:

one or more memories; and

one or more processors to:

transmit, to a first neighbor network device that is communicatively connected to the network device, information indicating that the network device supports bit indexed explicit replication (BIER),

wherein the network device does not support BIER;

receive a multicast packet from the first neighbor network device based on transmitting the information indicating that the network device supports BIER,

wherein the multicast packet includes a first BIER label associated with the network device,

wherein the first BIER label indicates that the network device supports BIER;

replace the first BIER label included in the multicast packet with a second BIER label associated with a second neighbor network device that is communicatively connected to the network device,

wherein the second neighbor network device is a BIER-enabled network device that performs BIER functions for the network device; and

transmit, after replacing the first BIER label included in the multicast packet with the second BIER label, the multicast packet to the second neighbor network device to cause the second neighbor network device to tunnel the multicast packet to a third neighbor network device that supports BIER.

2. The network device of claim 1 , wherein the one or more processors, when transmitting the multicast packet to the second neighbor network device, are to:

transmit the multicast packet to the second neighbor network device to further cause the second neighbor network device to tunnel the multicast packet to one or more third neighbor network devices through the network device.

3. The network device of claim 1 , wherein the one or more processors are further to:

receive the second BIER label from the second neighbor network device,

wherein the one or more processors, when replacing the first BIER label included in the multicast packet with the second BIER label, are to:

replace the first BIER label included in the multicast packet with the second BIER label based on receiving the second BIER label from the second neighbor network device.

4. The network device of claim 1 , wherein a plurality of copies of the multicast packet is encapsulated in an additional encapsulation layer.

5. The network device of claim 1 , wherein the one or more processors, when transmitting the multicast packet to the second neighbor network device, are to:

transmit the multicast packet to the second neighbor network device to further cause the second neighbor network device to be provisioned with information indicating that the network device does not support BIER.

6. The network device of claim 1 , wherein the one or more processors are further to:

transmit, to the second neighbor network device, information indicating that the network device does not support BIER.

7. The network device of claim 1 , wherein the one or more processors, when transmitting the information indicating that the network device supports BIER, are to:

transmit the information via interior gateway protocol (IGP) control plane signaling.

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:

transmit, to a first neighbor network device that is communicatively connected to the network device, information indicating that the network device supports bit indexed explicit replication (BIER),

wherein the network device does not support BIER;

receive a multicast packet from the first neighbor network device based on transmitting the information indicating that the network device supports BIER,

wherein the multicast packet includes a first BIER label associated with the network device,

wherein the first BIER label indicates that the network device supports BIER;

replace the first BIER label included in the multicast packet with a second BIER label associated with a second neighbor network device that is communicatively connected to the network device,

wherein the second neighbor network device is a BIER-enabled network device that performs BIER functions for the network device; and

transmit, after replacing the first BIER label included in the multicast packet with the second BIER label, the multicast packet to the second neighbor network device to cause the second neighbor network device to:

tunnel the multicast packet to a third neighbor network device that supports BIER, and

encapsulate the multicast packet in an additional encapsulation layer.

9. The non-transitory computer-readable medium of claim 8 , wherein the additional encapsulation layer includes at least one of:

a multiprotocol label switching (MPLS) header,

a user datagram protocol (UDP) header, or

an Ethernet header.

10. The non-transitory computer-readable medium of claim 8 , wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to:

transmit, to the second neighbor network device, information indicating that the network device does not support BIER.

11. The non-transitory computer-readable medium of claim 8 , wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to:

receive the second BIER label from the second neighbor network device,

wherein the one or more instructions, that cause the one or more processors to replace the first BIER label included in the multicast packet with the second BIER label, cause the one or more processors to:

replace the first BIER label included in the multicast packet with the second BIER label based on receiving the second BIER label from the second neighbor network device.

12. The non-transitory computer-readable medium of claim 8 , wherein the one or more instructions, that cause the one or more processors to transmit the multicast packet to the second neighbor network device, cause the one or more processors to:

transmit the multicast packet to the second neighbor network device to further cause the second neighbor network device to tunnel a plurality of copies of the multicast packet to a plurality of fourth neighbor network devices through the network device.

13. The non-transitory computer-readable medium of claim 8 , wherein the one or more instructions, that cause the one or more processors to transmit the multicast packet to the second neighbor network device, cause the one or more processors to:

transmit the multicast packet to the second neighbor network device to further cause the second neighbor network device to be provisioned with information indicating that the network device does not support BIER.

14. The non-transitory computer-readable medium of claim 8 , wherein the one or more instructions, that cause the one or more processors to transmit the information indicating that the network device supports BIER, cause the one or more processors to:

transmit the information via interior gateway protocol (IGP) control plane signaling.

15. A method, comprising:

transmitting, by a network device and to a first neighbor network device, information indicating that the network device supports bit indexed explicit replication (BIER),

wherein the network device does not support BIER, and

wherein the first neighbor network device is communicatively connected to the network device;

receiving, at the network device, a multicast packet from the first neighbor network device based on transmitting the information indicating that the network device supports BIER,

wherein the multicast packet includes a first BIER label associated with the network device,

wherein the first BIER label indicates that the network device supports BIER;

replacing, by the network device, the first BIER label included in the multicast packet with a second BIER label associated with a second neighbor network device,

wherein the second neighbor network device is communicatively connected to the network device, and

wherein the second neighbor network device is a BIER-enabled network device that performs BIER functions for the network device; and

transmitting, by the network device after replacing the first BIER label included in the multicast packet with the second BIER label, the multicast packet to the second neighbor network device to cause the second neighbor network device to:

tunnel the multicast packet to a third neighbor network device that supports BIER through the network device, and

encapsulate the multicast packet in an additional encapsulation layer.

16. The method of claim 15 , wherein a first connection between the network device and the second neighbor network device has greater bandwidth relative to a second connection between the network device and the first neighbor network device.

17. The method of claim 15 , wherein transmitting the multicast packet to the second neighbor network device includes:

transmitting the multicast packet to the second neighbor network device to further cause the second neighbor network device to:

be provisioned with information indicating that the network device does not support BIER.

18. The method of claim 15 , wherein the tunnel is a unicast tunnel.

19. The method of claim 15 , wherein the tunnel is a multicast tunnel.

20. The method of claim 15 , wherein transmitting the information indicating that the network device supports BIER comprises:

transmitting the information via interior gateway protocol (IGP) control plane signaling.