SR Seamless BFD for Static Tunnels

You can enable seamless BFD (S-BFD) over non-colored and colored static segment routing-traffic engineering (SR-TE) label switched paths (LSPs) with first-hop label resolution. The software uses S-BFD as a fast mechanism to detect path failures and to trigger global convergence. S-BFD requires fewer state changes than BFD requires, thus speeding up the reporting of path failures. Given a segment routing tunnel with one or multiple primary LSPs and optionally a secondary LSP, you can enable S-BFD individually on any of those LSPs. If an S-BFD session goes down, the software updates the segment routing tunnel's route by deleting the next hops of the failed LSPs. If the first-hop label of the LSP points to more than one immediate next hop, the kernel continues to send S-BFD packets if at least one next hop is available (underlying next-hop reachability failure detection must be faster than the duration of the S-BFD detection timer).