Network data routing protection cycles for automatic protection switching
View Patent ↗A computer network processes data packets in the event of a network link failure. The network includes a plurality of routers that deliver data packets to the network via a plurality of links. At least one router includes a protection cycle manager. The protection cycle manager has a protection cycle packet identifier and a protection cycle packet processor. The protection cycle packet identifier identifies, as protection cycle packets, data packets having a specific protection cycle format. The protection cycle packet processor processes protection cycle packets to determine whether the packet destination corresponds to the routing node, and if the packet destination corresponds to the routing node, the protection cycle packet is treated by the routing node as a data packet received from the packet source via the failed link. Otherwise, if the packet destination does not correspond to the routing node, the protection cycle packet is sent to a protection cycle node for the routing node.
1. Apparatus comprising:
a first MPLS router being capable of receiving packets from a secondary LSP, the packets being sent to the first MPLS router from a second MPLS router that forwards packets over the secondary LSP in response to an event indicating that the secondary LSP should be used instead of a primary LSP;
the first MPLS router being capable of forwarding the packets on the secondary LSP if the first MPLS router is not located at the termination point of the secondary LSP, and being capable of forwarding the packets on the primary path if the first MPLS router is located at the termination point of the secondary LSP.
2. The apparatus of claim 1 wherein the second MPLS router adds a label to packets being forwarded over the secondary LSP, and wherein the first MPLS router is capable of examining the label to identify received packets as being forwarded over the secondary LSP.
3. The apparatus of claim 2 wherein the second MPLS router adds a second label to packets being forwarded over the secondary LSP, and wherein the first MPLS router is capable of examining the second label to determine whether the first MPLS router is located at the termination point of the secondary LSP.
4. The apparatus of claim 2 wherein the second MPLS router adds another label to packets being forwarded over the secondary LSP, and wherein the first MPLS router examines the label to ascertain how to forward the packets over the primary LSP.
5. The apparatus of claim 1 wherein the second MPLS router adds a plurality of labels to packets being forwarded over the secondary LSP, the plurality of labels forming a label stack, and wherein the first MPLS router examines the label stack to identify received packets as being forwarded over the secondary LSP and to ascertain how to forward the packets over the primary LSP.
6. The apparatus of claim 1 wherein the second MPLS router adds a plurality of labels to packets being forwarded over the secondary LSP, the plurality of labels forming a label stack, and wherein the first MPLS router is capable of examining the label stack to identify received packets as being forwarded over the secondary LSP and to ascertain whether the second MPLS router is located at the termination point of the secondary LSP.
7. A method comprising the steps of:
receiving by a first MPLS router packets from a secondary LSP, the packets being sent to the first MPLS router from a second MPLS router that forwards packets over the secondary LSP in response to an event indicating that the secondary LSP should be used instead of a primary LSP;
forwarding by the first MPLS router the packets on the secondary LSP if the first MPLS router is not located at the termination point of the secondary LSP, and forwarding by the first MPLS router the packets on the primary path if the first MPLS router is located at the termination point of the secondary LSP.
8. The method of claim 7 wherein the second MPLS router adds a first label to packets being forwarded over the secondary LSP, and wherein the step of receiving by a first MPLS router comprises the step of examining the first label to identify received packets as being forwarded over the secondary LSP.
9. The method of claim 8 wherein the second MPLS router adds a second label to packets being forwarded over the secondary LSP, and wherein the step of forwarding by the first MPLS router comprises the step of examining the second label to determine whether the first MPLS router is located at the termination point of the secondary LSP.
10. The method of claim 7 wherein the second MPLS router adds a second label to packets being forwarded over the secondary LSP, and wherein the step of forwarding by the first MPLS router comprises the step of examining the second label to ascertain how to forward the packets over the primary LSP.
11. The method of claim 7 wherein the second MPLS router adds a plurality of labels to packets being forwarded over the secondary LSP, the plurality of labels forming a label stack, and wherein the step of receiving by the first MPLS router includes the step of examining the label stack to identify received packets as being forwarded over the secondary LSP, and wherein the step of forwarding by the first MPLS router includes the step of examining the label stack to ascertain how to forward the packets over the primary LSP.
12. The method of claim 7 wherein the second MPLS router adds a plurality of labels to packets being forwarded over the secondary LSP, the plurality of labels forming a label stack, and wherein the step of receiving by the first MPLS router includes the step of examining the label stack to identify received packets as being forwarded over the secondary LSP, and wherein the step of forwarding by the first MPLS router includes the step of examining the label stack to ascertain whether the second MPLS router is located at the termination point of the secondary LSP.
13. Apparatus comprising:
a first MPLS router capable of forwarding packets over a primary LSP;
the first MPLS router capable of forwarding packets over a secondary LSP in response to an event indicating that the secondary LSP should be used instead of the primary LSP;
a second MPLS router capable of receiving packets and identifying the packets as being received from the secondary LSP;
the second MPLS router capable of forwarding the packets received from the secondary LSP on the primary LSP if the second MPLS router is located at the termination point of the secondary LSP, or of forwarding the packets received from the secondary LSP on the secondary LSP if the second MPLS router is not located at the termination point of the secondary LSP.
14. The apparatus of claim 13 wherein the first MPLS router adds a first label to packets being forwarded over the secondary LSP, and wherein the second MPLS router is capable of identifying the packets as being received over the secondary LSP by examining the first label to identify received packets as being forwarded over the secondary LSP.
15. The apparatus of claim 14 wherein the first MPLS router adds a second label to packets being forwarded over the secondary LSP, and wherein the second MPLS router examines the label to ascertain whether the second MPLS router is located at the termination point of the secondary LSP.
16. The apparatus of claim 14 wherein the first MPLS router adds a second label to packets being forwarded over the secondary LSP, and wherein the second MPLS router examines the label to ascertain how to forward packets over the primary LSP.
17. The apparatus of claim 13 wherein the first MPLS router adds a plurality of labels to packets being forwarded over the secondary LSP, the plurality of labels forming a label stack, and wherein the second MPLS router examines the label stack to identify received packets as being received from the secondary LSP and to ascertain whether the second MPLS router is located at the termination point of the secondary LSP.
18. The apparatus of claim 13 wherein the first MPLS router adds a plurality of labels to packets being forwarded over the secondary LSP, the plurality of labels forming a label stack, and wherein the second MPLS router examines the label stack to identify received packets as being received from the secondary LSP and to ascertain how to forward packets over the primary LSP.
19. The apparatus of claim 13 wherein the event is a link failure on the primary LSP, and wherein the secondary LSP traverses the link failure.
20. A method comprising the steps of:
forwarding packets by a first MPLS router over a primary LSP;
forwarding packets by the first MPLS router over a secondary LSP in response to an event indicating that the secondary LSP should be used instead of the primary LSP;
receiving packets by a second MPLS router and identifying the packets as being received from the secondary LSP;
forwarding by the second MPLS router the packets received from the secondary LSP on the primary LSP if the second MPLS router is located at the termination point of the secondary LSP, or forwarding by the second MPLS router the packets received from the secondary LSP on the secondary LSP if the second MPLS router is not located at the termination point of the secondary LSP.
21. The method of claim 20 further comprising the step of adding by the first MPLS router a first label to packets being forwarded over the secondary LSP, and wherein the second MPLS router identifies the packets as being received over the secondary LSP by examining the first label to identify received packets as being forwarded over the secondary LSP.
22. The method of claim 21 further comprising the step of adding by the first MPLS router a second label to packets being forwarded over the secondary LSP, and wherein the second MPLS router ascertains whether the second MPLS router is located at the termination point of the secondary LSP by examining the second label.
23. The method of claim 21 further comprising the step of adding by the first MPLS router a second label to packets being forwarded over the secondary LSP, and wherein the second MPLS router ascertains how to forward packets over the primary LSP by examining the second label.
24. The method of claim 20 further comprising the step of adding by the first MPLS router a plurality of labels to packets being forwarded over the secondary LSP, the plurality of labels forming a label stack, and wherein the second MPLS router examines the label stack to identify received packets as being received from the secondary LSP and to ascertain whether the second MPLS router is located at the termination point of the secondary LSP.
25. The apparatus of claim 20 further comprising the step of adding by the first MPLS router a plurality of labels to packets being forwarded over the secondary LSP, the plurality of labels forming a label stack, and wherein the second MPLS router examines the label stack to identify received packets as being received from the secondary LSP and to ascertain how to forward packets over the primary LSP.