PROTECTION IN A RING NETWORK OF LABEL SWITCHING ROUTERS

摘要

A first label switch router (LSR) in a ring network protects multiple service label switched paths (LSPs) using a single bidirectional circular protection LSP tunnel. The first LSR monitors for a failure report responsive to detecting disconnection with a neighbor LSR. The report indirectly indicates either failure of a link to the neighbor LSR or failure of the neighbor LSR itself. Responsive to receiving the report, the first LSR locally re-routes any labeled packets of service LSPs headed toward the failure by placing those packets onto the tunnel in a direction away from the failure, and locally merges any labeled packets received over the tunnel into respective service LSPs headed away from the failure. Local re-routing entails the first LSR dynamically selecting between next-hop service labels and next-next-hop service labels for packets placed onto the tunnel, based on whether the failure is of the link or of the neighbor LSR.

主权项

1. A method in a ring network of label switching routers (LSRs) for protecting multiple service label switched paths (LSPs) with a single bidirectional circular protection LSP tunnel established around the ring network in advance of any failure, wherein the method is implemented by a first LSR and is characterized by:
responsive to detecting disconnection with a neighbor LSR, monitoring for a report that either indirectly indicates failure of a link to the neighbor LSR by reporting complementary disconnection with the first LSR or indirectly indicates failure of the neighbor LSR itself by confirming disconnection with the neighbor LSR; and responsive to receiving the report:
locally re-routing any labeled packets of service LSPs headed toward the failure by placing those packets onto the tunnel, in a direction away from the failure, with either next-hop service labels or next-next-hop service labels depending on whether the failure is of said link or of said neighbor LSR; andlocally merging any labeled packets received over the tunnel into respective service LSPs headed away from the failure.