VIRTUAL ROOT BRIDGE

A network includes a plurality of network clusters. Each network cluster includes a plurality of nodes. At least one of the plurality of nodes includes a portal node. A portal node is a node with at least one link that crosses a boundary of the network cluster. Each portal node is configured to communicate detection packets for detecting the existence of other portal nodes within the network cluster. Each portal node is configured to communicate with nodes within the network cluster associated with the respective portal node to indicate that the respective portal node is a predetermined number of hops away from a virtual root bridge associated with the network cluster.