Control for BFD return path

1. A method to establish a bidirectional forwarding detection, BFD, session with an explicit return path to enable detection of data plane failures between an active node and a passive node in a network in the explicit return path, the method for the passive node comprising:

receiving, by the passive node, a label switched path, LSP, ping including a BFD discriminator type length value, TLV, of the active node and a BFD return path TLV including information of a return path to the active node;

verifying, by the passive node, availability of the return path prior to establishing the BFD session; and

sending, by the passive node, BFD control packets to the active node using the return path to detect a failure on the return path, in response to verified availability of the return path.

2. The method of claim 1 , further comprising:

associating the return path with the BFD discriminator TLV of the active node.

3. The method of claim 1 , further comprising:

notifying the active node of an error indicating the return path is unavailable using an LSP ping reply in response to the verifying indicating that the return path is not available or valid.

4. The method of claim 1 , wherein the verifying includes verifying a Target Forwarding Equivalency Class, FEC, Stack TLV in the LSP ping.

5. The method of claim 1 , wherein the return path is indicated by a multi-protocol label, MPLS, stack.

6. A network device functioning as a passive node, the network device configured to establish a bidirectional forwarding detection, BFD, session with an explicit return path to enable detection of data plane failures between an active node and the passive node in the explicit return path, the network device comprising:

a non-transitory machine-readable storage medium configured to store a BFD module and a return path module; and

a network processor communicatively coupled to the non-transitory machine-readable storage medium, the network processor configured to execute the BFD module and the return path module, the BFD module configured to receive a label switched path, LSP, ping including a BFD discriminator type length value, TLV, of the active node and a BFD return path TLV including information of a return path to the active node, the return path module configured to verify availability of the return path prior to establishment of the BFD session, and to send BFD control packets to the active node using the return path to detect a failure on the return path, in response to verified availability of the return path.

7. The network device of claim 6 , wherein the return path module is further to associate the return path with the BFD discriminator TLV of the active node.

8. The network device of claim 6 , wherein the return path module is further to notify the active node of an error indicating the return path is unavailable using an LSP ping reply, in response to the verifying indicating that the return path is not available or valid.

9. The network device of claim 6 , wherein the return path module verifies a Target Forwarding Equivalency Class, FEC, Stack TLV in the LSP ping.

10. The network device of claim 6 , wherein the return path is indicated by a multi-protocol label, MPLS, stack.

11. A computing device executing a plurality of virtual machines for implementing network function virtualization, NFV, wherein a virtual machine from the plurality of virtual machines is configured to establish a bidirectional forwarding detection, BFD, session with an explicit return path to enable detection of data plane failures between an active node and a passive node in the explicit return path, the virtual machine instantiated by a hypervisor or virtual machine monitor, the virtual machine functioning as the passive node, the computing device comprising:

a non-transitory machine-readable storage medium configured to store a BFD module and a return path module; and

a processor communicatively coupled to the non-transitory machine-readable storage medium, the processor configured to execute the virtual machine that executes the BFD module and the return path module, the BFD module configured to receive a label switched path, LSP, ping including a BFD discriminator type length value, TLV, of the active node and a BFD return path TLV including information of a return path to the active node, the return path module configured to verify availability of the return path prior to establishment of the BFD session, and send BFD control packets to the active node using the return path to detect a failure on the return path, in response to verified availability of the return path.

12. The computing device of claim 11 , wherein the return path module is further to associate the return path with the BFD discriminator TLV of the active node.

13. The computing device of claim 11 , wherein the return path module is further to notify the active node of an error indicating the return path is unavailable using an LSP ping reply in response to the verifying indicating that the return path is not available or valid.

14. The computing device of claim 11 , wherein the return path module verifies a Target Forwarding Equivalency Class, FEC, Stack TLV in the LSP ping.

15. The computing device of claim 11 , wherein the return path is indicated by a multi-protocol label, MPLS, stack.

16. A control plane device configured to implement at least one centralized control plane for a software defined network, SDN, the centralized control plane configured to establish a bidirectional forwarding detection, BFD, session with an explicit return path to enable detection of data plane failures between an active node and a passive node in the explicit return path, the control plane device servicing the passive node, the control plane device comprising:

a non-transitory machine-readable storage medium configured to store a BFD module and a return path module; and

a processor communicatively coupled to the non-transitory machine-readable storage medium, the processor configured to execute the BFD module and the return path module, the BFD module configured to receive a label switched path, LSP, ping including a BFD discriminator type length value, TLV, of the active node and a BFD return path TLV including information of a return path to the active node, the return path module configured to verify availability of the return path prior to establishment of the BFD session, and send BFD control packets to the active node using the return path to detect a failure on the return path, in response to verified availability of the return path.

17. The control plane device of claim 16 , wherein the return path module is further to associate the return path with the BFD discriminator TLV of the active node.

18. The control plane device of claim 16 , wherein the return path module is further to notify the active node of an error indicating the return path is unavailable using an LSP ping reply in response to the verifying indicating that the return path is not available or valid.

19. The control plane device of claim 16 , wherein the return path module verifies a Target Forwarding Equivalency Class, FEC, Stack TLV in the LSP ping.

20. The control plane device of claim 16 , wherein the return path is indicated by a multi-protocol label, MPLS, stack.