Method for connecting between networks, virtual router, and system for connecting between networks by using this virtual router

摘要

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. Substitute ports are provided in both routers, and these substitute ports are connected to each other. When a trouble has occurred on the route, a router in the backup state is changed to a master state, and a packet from a PC or the Internet is forwarded on the route via the substitute ports.