2.3 Spanning Tree Alg. Contd.
nWhen failures occur (bridges
continuously send outconfiguration messages to determine their well being), new shortest
paths have to be calculated.
nWhen new LAN segments or bridges are added to the topology, new shortest paths have to be calculated.
nWhen a topology spans across a WAN, remote bridges are used at each end of the long distance WAN
link. The spanning tree should make sure that the WAN link is the
least loaded (another reason for using bridge priorities
to manipulate the algorithm’s operation and outcome).