A fast reroute (FRR) technique is implemented at the edge of a network. In accordance with the technique, if an edge device detects a node or link failure that prevents it from communicating with a neighboring routing domain, the edge device reroutes at least some data packets addressed to that domain...http://www.google.fr/patents/US7633859?utm_source=gb-gplus-shareBrevet US7633859 - Loop prevention technique for MPLS using two labels
Loop prevention technique for MPLS using two labels