Patent ID: 7916757

Claim:
A method of operating a slave router in a stack of network routers which are interconnected and organised to constitute a single routing entity, said routers comprising a single master router and at least one slave router, wherein each of the routers is capable of performing fully a routing protocol, the method comprising: causing the slave router to snoop net update messages from neighbors of a master router, only said master router fully performing said routing protocol, only said master router generating and transmitting net advertisements in accordance with said routing protocol and receiving all types of net database update messages from its neighbors; receiving from the master router verification data representing an incremental update of the master router's net database; making a comparison of verification data with corresponding data in the slave router's net database so as to determine whether said slave router's net database is synchronized with the master router's net database; and requesting a net advertisement from said master router if said comparison indicates that the net database of the slave router is not synchronized with said master router's net database.