Summary
In this chapter, the focus shifted from the previously discussed TI-LFA mechanism, which provides a backup path to protect traffic on the primary path, to exploring the microloop avoidance mechanism. This mechanism is crucial in scenarios where changes in network topology could cause traffic to briefly loop due to the delayed convergence of the IGP routing protocol, as routers update at different times.
The microloop avoidance mechanism works by creating an explicit MPLS tunnel for the primary path to the repair node, calculated using the same method as TI-LFA. This explicit tunnel, using MPLS labels and label stack, continues to forward traffic while IP routing converges.
On the Cisco IOS XR platform, a 60-second maximum time could be provisioned for network convergence. After this period, the explicit tunnel is replaced by the post-convergence path.
In the lab scenario, when the P8-P4 link was activated, traffic from P2 was expected to switch from the P2-P3 link...
