A plurality of routers are connected within the same network and are set in a relationship of a master and a backup according to the mounted VRRP, thereby to build up a virtual router. The virtual router transmits a packet that is input from the network or an external network, to a destination network....http://www.google.ca/patents/US20020184387?utm_source=gb-gplus-sharePatent US20020184387 - Method for connecting between networks, virtual router, and system for connecting between networks by using this virtual router
