SR based Loop-free implementation

Microloops are transient packet loops that occur in the network following a topology change (link down, link up, node fault, or metric change events). Microloops are caused by the non-simultaneous convergence of different nodes in the network. If nodes converge and send traffic to a neighbor node that has not converged yet, traffic may be looped between these two nodes, resulting in packet loss, jitter, and out-of-order packets. This document presents some optional implementation methods aimed at providing loop avoidance in the case of IGP network convergence event in different scenarios.