Virtual router discovery system

Abstract

A router discovery system for virtual routers automatically builds a multicast virtual network over an existing network topology. The virtual routers send out 'heartbeats' across the Internet Protocol (IP) multicast network marked with a Time to Live (TTL) value containing the number of hops that the packet can take through the network before it gets discarded. The originating router gets an estimate of how far away the receiving router is when it receives the response packet from the receiving router (i.e. the receiving router is less than TTL hops away from the originating router). The invention uses the TTL values to find the closest routers. It balances the efficiency of the IP network connections with the distance of the routers to create a balanced network topology and establishes connections with the routers that meet these criteria. When a router comes alive, it sends out multicast packets across the network. Any routers that pick up the packets wait for a random amount of time and after the waiting period, if a router does not hear from any of the other routers that a connection was made, it establishes a connection with the new router. Ping messages are periodically sent between the routers that have established connections between themselves, testing the connection between the routers. The invention automatically and dynamically adapts to changes in the network topology. If a virtual router finds a more efficient connection to another router, it drops the less efficient connection. When a router goes down, the router's neighbors opens up connections to their next-nearest neighbors until the connectivity of the virtual network is restored.