Entropy prefix segment identifier for use with entropy label in segment routing networks

1. A method comprising:

receiving at an ingress node in a segment routing network, an entropy prefix segment identifier;

generating at the ingress node, a label stack comprising the entropy prefix segment identifier and an entropy label beneath the entropy prefix segment identifier; and

transmitting at the ingress node, a packet comprising the label stack using the entropy prefix segment identifier as a transport label and an entropy label identifier;

wherein the entropy label is a load balancing label.

2. The method of claim 1 wherein the entropy prefix segment identifier is advertised with a different algorithm than a prefix segment identifier.

3. The method of claim 2 wherein said algorithm instructs the ingress node to push the entropy label beneath the entropy prefix segment identifier.

4. The method of claim 1 wherein the entropy prefix segment identifier is associated with a same loopback as a related prefix segment identifier.

5. The method of claim 1 wherein the entropy prefix segment identifier is associated with a different loopback than a related prefix segment identifier.

6. The method of claim 1 wherein the entropy prefix segment identifier is advertised by an egress node in an IGP (Interior Gateway Protocol) advertisement.

7. The method of claim 1 wherein PHP (Penultimate Hop Popping) is disabled and an egress node is configured to pop the entropy prefix segment identifier and the entropy label upon receiving the packet.

8. The method of claim 1 wherein a segment of the segment routing network is configured for double pop on PHP (Penultimate Hop Popping) and wherein a PHP node is operable to pop the entropy prefix segment identifier and the entropy label.

9. An apparatus comprising:

an interface for receiving at an ingress node in a segment routing network, an entropy prefix segment identifier;

a processor for generating a label stack comprising the entropy prefix segment identifier and an entropy label beneath the entropy prefix segment identifier and transmitting a packet comprising the label stack using the entropy prefix segment identifier as a transport label and an entropy label identifier; and

memory for spring the entropy prefix segment identifier;

wherein the entropy label is a load balancing label.

10. The apparatus of claim 9 wherein the entropy prefix segment identifier is received in an advertisement with a different algorithm than a prefix segment identifier.

11. The apparatus of claim 10 wherein said algorithm is configured to instruct the ingress node to push the entropy label beneath the entropy prefix segment identifier.

12. The apparatus of claim 9 wherein the entropy prefix segment identifier is associated with a same loopback as a related prefix segment identifier.

13. The apparatus of claim 9 wherein the entropy prefix segment identifier is associated with a different loopback than a related prefix segment identifier.

14. The apparatus of claim 9 wherein the entropy prefix segment identifier is advertised by an egress node in an IGP (Interior Gateway Protocol) advertisement.

15. The apparatus of claim 9 wherein PHP (Penultimate Hop Popping) is disabled and an egress node is configured to pop the entropy prefix segment identifier and the entropy label upon receiving the packet.

16. The apparatus of claim 9 wherein a segment of the segment routing network is configured for double pop on PHP (Penultimate Hop Popping) and wherein a PHP node is configured to pop the entropy prefix segment identifier and the entropy label.

17. Logic encoded on one or more non-transitory computer readable media for execution and when executed operable to:

process at an ingress node in a segment routing network, an entropy prefix segment identifier;

generate a label stack comprising the entropy prefix segment identifier and an entropy label beneath the entropy prefix segment identifier; and

transmit a packet comprising the label stack using the entropy prefix segment identifier as a transport label and an entropy label identifier;

wherein the entropy label is a load balancing label.

18. The logic of claim 17 wherein the processor is operable to process the entropy prefix segment identifier advertised with a different algorithm than a prefix segment identifier and wherein said algorithm instructs the ingress node to push the entropy label beneath the entropy prefix segment identifier.

19. The logic of claim 17 wherein the ingress node is operable to transmit traffic in an EVPN/L2VPN (Ethernet Virtual Private Network/Layer 2 Virtual Private Network).

20. The logic of claim 17 wherein the ingress node is operable to transmit traffic for (SR-TE) Segment Routing-Traffic Engineering.