Users Guide

274 Stacking
JOIN messages upstream. The control plane updates the driver with
checkpointed unicast routes. The forwarding plane reconciles layer-3
hardware tables.
The OSPF graceful restart finishes, and the control plane deletes any stale
unicast routes not relearned at this point. The forwarding plane reconciles
layer-3 multicast hardware tables. Throughout the process, the hosts continue
to receive their multicast streams, possibly with a short interruption as the
top aggregation router learns that one of its LAG members is down. The hosts
see no more than a 50 ms interruption in unicast connectivity.