A working label switched path (LSP) between neighbor label switched
routers (LSRs) in a ring network that utilizes label switching is
protected by an LSP that connects the neighbor LSRs of the working LSP in
an opposite direction to the working LSP. If the working LSP fails, then
packets are switched to the protection LSP. Switched packets traverse the
protection LSP until they reach the neighbor LSR that they would have
reached had the packets traversed the working LSP. Time-to-live (TTL)
values of packets that traverse the protection LSP are adjusted to
account for the number of hops on the protection LSP so that the TTL
values of the packets are the same after traversing the protection LSP as
they would have been had they traversed the working LSP. After traversing
the protection LSP packets can be switched back to the working LSP or
switched to a next hop LSP.