Patent ID: 7567505
Filing Date: 2009-07-28
Classification: H04L

Abstract:
1. A redundancy packet transmission system, comprising: an active router and a standby router each of which has at least first and second virtual routers logically realized therein, and an internal wiring conductor to connect between said active router and said standby router, wherein said first virtual router of the active router is configured to transmit packets only with a first internet service provider and said second virtual router of the active router is configured to transmit packets only with a second internet service provider, each of said active router and said standby router includes: a network interface for transmitting packets; a processor for processing the packets transmitted from and to the internet service providers; a table memory for storing routing information of said first internet service provider necessary for routing packets from said first internet service provider only via said first virtual router logically realized in the active or standby router and for storing routing information of said second internet service provider necessary for routing packets from said second internet service provider only via said second virtual router logically realized in the active or standby router; and a program memory for storing in advance a program to be executed by said processor provided in the active or standby router, wherein when said active router operates normally, said at least first and second virtual routers logically realized on said active router are activated and said at least first and second virtual routers logically realized on said standby router are not activated, said respective routing information of said first or second internet service provider stored in the table memory of the active router is independently managed by only the first or second virtual router logically realized in said active router, and said respective routing information of said first or second internet service provider stored in the table memory of the standby router is independently managed by only a first or second virtual router logically realized in said standby router, wherein when said active router has a trouble that occurs therein, said processor provided in said active router independently synchronizes (1) said routing information of said first internet service provider managed by the first virtual router of the active router with routing information to be managed by the first virtual routers of said standby router, and (2) said routing information of said second internet service provider managed by the second virtual router of the active router with routing information to be managed by the second virtual routers of said standby router, by: transmitting through the internal wiring conductor from said active router to said standby router a packet including a virtual router configuration flag and identification information of said first or second virtual router logically realized in said active router, receiving a response signal relative to said identification information from said first or second virtual router logically realized in said standby router, and transmitting and storing said routing information of said first and second internet service providers from said active router to said standby router, wherein the transmitting and storing are done independently without mixing said routing information of said first and second internet service providers.