Notifying of a LSP failure

1. A method for notifying of a Label Switched Path (LSP) failure, applied to a Label Switching Router (LSR) in a ring network that uses Multi-Protocol Label Switching Transport Profile (MPLS TP), the ring network comprising at least one work LSP forwarding packets along a first direction and a protection LSP loop forwarding packets along a second direction, the first direction being opposite to the second direction, and the method comprising:

forwarding packets via the work LSP and detecting whether a link between the LSR and a neighbor LSR has failed; and

in response to detecting that a link between the LSR and a downstream neighbor LSR on the work LSP has failed and receiving a Signal Failure (SF) message sent by another LSR on the work LSP, inserting into a packet an incoming working label of the another LSR as an inner layer label of the packet, inserting into the packet an outgoing working label of the LSR on the protection LSP loop as an outer layer label of the packet, and sending the packet along the second direction via the protection LSP loop.

2. The method of claim 1 , further comprising:

in response to detecting that a link between the LSR and an upstream neighbor LSR on the work LSP has failed, sending a SF message along the first direction, popping an outer layer of a packet received via the protection LSP loop, and forwarding the packet via the work LSP.

3. The method of claim 1 , further comprising:

sending a Restore Test (RT) message along the first direction after receiving the SF message sent by the another LSR, wherein the RT message is to determine whether the link between the LSR and the downstream neighbor LSR has been restored.

4. The method of claim 3 , after sending the SF message along the first direction, the method further comprising:

when receiving the RT message along the first direction, stopping sending of the SF message along the first direction and sending a Wait to Restore (WTR) message along the first direction, wherein the WTR message is to notify that the link between the LSR and the upstream neighbor LSR of the work LSP has been restored.

5. The method of claim 4 , the method further comprising:

sending a Restore Over (RO) message along the first direction when receiving the WTR message, wherein the RO message is to notify that the link restoration has finished.

6. The method of claim 5 , the method further comprising:

sending a No Request (NR) message along the first direction when receiving the RO message.

7. The method of claim 6 , wherein the ring network comprises a protection LSP loop on the first direction, and wherein the SF message, the RT message, the WTR message, the RO message, and the NR message are received or sent via the protection LSP loop on the first direction.

8. An apparatus for notifying of a Label Switched Path (LSP) failure, applied to a Label Switching Router (LSR) in a ring network that uses Multi-Protocol Label Switching Transport Profile (MPLS TP), the ring network comprising at least one work LSP forwarding packet along a first direction and a protection LSP loop forwarding packet along a second direction, the first direction being opposite to the second direction, wherein the apparatus comprises:

a failure detecting module, a notification receiving/sending module and a failure processing module;

the failure detecting module is to detect whether a link between the LSR and a neighbor LSR has failed;

the notification receiving/sending module is to determine whether a signal failure (SF) message is received from another LSR; and

the failure processing module is to, after the failure detecting module has detected that a link between the LSR and a downstream neighbor LSR on the work LSP has failed and the notification receiving/sending module has received the SF message sent by the another LSR, insert into a packet an incoming working label of the another LSR on the work LSP as an inner layer label of the packet, insert into the packet an outgoing working label of the LSR on the protection LSP loop as an outer layer label of the packet, and send the packet along the second direction via the protection LSP loop.

9. The apparatus of claim 8 , wherein

the notification receiving/sending module is further to send a Signal Failure (SF) message along the first direction after the failure detecting module has detected that a link between the LSR and an upstream neighbor LSR has failed; and

the failure processing module is further to, after the failure detecting module has detected that a link between the LSR and the upstream neighbor LSR on the work LSP has failed and the notification receiving/sending module has received a packet via the protection LSP loop, pop an outer layer of the packet received via the protection LSP loop, and forward the packet via the work LSP.

10. The apparatus of claim 8 , wherein the notification receiving/sending module is further to, after the SF message sent by the another LSR has been received and a failure in the link between the LSR and the downstream neighbor LSR on the work LSP has been detected by the failure detecting module, send a Restore Test (RT) message along the first direction, wherein the RT message is to determine whether the link between the LSR and the downstream neighbor LSR has been restored.

11. The apparatus of claim 10 , wherein the notification receiving/sending module is further to, after the SF message has been sent along the first direction, send a Wait to Restore (WTR) message along the first direction when the RT message is received along the first direction, wherein the WTR message is to notify that the link between the LSR and the upstream neighbor LSR of the work LSP has been restored.

12. The apparatus of claim 11 , wherein the notification receiving/sending module is further to, after the RT message has been sent along the first direction, send a Restore Over (RO) message along the first direction when the WTR message is received, wherein the RO message is to notify that the link restoration has finished.

13. The apparatus of claim 12 , wherein the notification receiving/sending module is further to send a No Request (NR) message when the RO message is received.

14. The apparatus of claim 13 , wherein the notification receiving/sending module is to receive and send the SF message, the RT message, the WTR message, the RO message, and the NR message on a MPLS TP Section layer.

15. The apparatus of claim 14 , wherein the ring network comprises a protection LSP loop on the first direction, and wherein the notification receiving/sending module is to receive or send the SF message, the RT message, the WTR message, the RO message, and the NR message via the protection LSP loop on the first direction.

16. A non-transitory computer readable storage medium storing instructions applied to a Label Switching Router (LSR) in a ring network that uses Multi-Protocol Label Switching Transport Profile (MPLS TP), the ring network comprising at least one work Label Switched Path (LSP) forwarding packet along a first direction and a protection LSP loop forwarding packet along a second direction, the first direction being opposite to the second direction, wherein the instructions are executable by a processor cause the processor to:

forward packets via the work LSP and detect whether a link between the LSR and a neighbor LSR has failed; and

in response to detecting that a link between the LSR and a downstream neighbor LSR on the work LSP has failed and receiving a Signal Failure (SF) message sent by another LSR on the work LSP, insert into a packet an incoming working label of the another LSR as an inner layer label of the packet, insert into the packet an outgoing working label of the LSR on the protection LSP loop as an outer layer label of the packet, and send the packet along the second direction via the protection LSP loop.

17. The non-transitory computer readable storage medium of claim 16 , the instructions are further to cause the processor to:

send a Restore Test (RT) message along the first direction after receiving the SF message sent by the another LSR, wherein the RT message is to determine whether the link between the LSR and the downstream neighbor LSR has been restored.

18. The non-transitory computer readable storage medium of claim 17 , the instructions are further to cause the processor to:

when receiving the RT message along the first direction, stop sending of the SF message along the first direction and send a Wait to Restore (WTR) message along the first direction, wherein the WTR message is to notify that the link between the LSR and the upstream neighbor LSR of the work LSP has been restored.

19. The non-transitory computer readable storage medium of claim 18 , the instructions are further to cause the processor to:

send a Restore Over (RO) message along the first direction when receiving the WTR message, wherein the RO message is to notify that the link restoration has finished.