Summary
The chapter explored SRLG (Shared Risk Link Group) scenarios, commonly found in large-scale production service provider networks, spanning across regions and countries. These networks often encounter SRLG links that extend beyond direct connections to routers, reaching into remote areas.
The TI-LFA Local SRLG-disjoint backup path is designed to exclude local SRLG links when recalculating paths post-convergence, aiming to fast-reroute traffic during failures. However, if a remote link along this backup path shares the same SRLG, the backup path may fail concurrently with the primary path, despite being installed in the RIB, FIB, and LFIB.
This issue arises due to the lack of SRLG information exchange among remote routers in a network, as highlighted in the problem statement involving the P7–P3
, P2–P3
, and P2–P7
links from the previous chapter.
The solution involved two main steps – first, advertising SRLG information from the P7 router P7...