Micro loop avoidance when IS-IS link fails

Junos OS allows to defer IS-IS route download when an IS-IS link fails-to avoid micro loops. When local links go down, the IS-IS protocol floods an entire area with the database. If the node connected to the local interface that has failed converges faster than the neighboring node, then the connected node redirects traffic to the converged path. This redirection can result in micro looping of traffic until the neighboring node converges. When the primary path of a protected node fails, the connected node does not need to converge quickly if the configured back up path is not impacted. In this case, traffic flow towards a converged path is deferred until all other nodes are converged.