Fast Reroute (FRR) rules state that if an LSP is traversing the nodes between the MP and the egress of a protected LSP, then the FRR LSP does not chose a bypass LSP for its backup path.
MPLS liberal bypass FRR protection is a special case where a rule of selecting a bypass LSP is liberalized and is allowed to select a bypass LSP even if it is traversing the FRR LSP downstream nodes between the MP and the egress.
The liberal bypass option reduces the number of bypasses, either dynamic or static, to create with the network.
