1. A communications network, comprising: a plurality of routing switches interconnected by communication links, wherein each of the routing switches comprises: one or more transceivers for being connected to associated links to one or more other routing switches in neighboring nodes; a switch fabric for routing information to and from said one or more transceivers; and one or more processors, said one or more processors for controlling said routing switch to: monitor a message from a neighboring node identifying attributes of said neighboring node; detect a change in said message from a previous message so as to identify a change in attributes of said neighboring node, corresponding to a topology change in said network; increment a session identifier, each said session identifier being associated with a different topology of said network; and communicate to other nodes in said network said change in topology by identifying an incremented session identifier along with information identifying said change in said topology of said network, wherein each of said routing switches associates said same incremented session identifier to said topology.