Why Vigor Router can not get routing information via RIP from other routers ?
RIP protocol has two versions: RIP v1 and RIP v2.
RIP v2 consists of RIP-2B and RIP-2M. Both RIP-2B and RIP-2M send the routing data in RIP-2 format; the difference being that RIP-2B uses subnet broadcasting while RIP-2M uses multicasting. Multicasting can reduce the load on non-router machines since they generally do not listen to the RIP multicast address and so will not receive the RIP packets.
Note: Vigor Router just support RIP-2M.
So if a router sends RIP information using RIPv1 or RIP-2B, Vigor Router will not accept it.
Below is a log captured on the LAN side of Vigor2910. The address 220.127.116.11 is a multicast address, 192.168.4.255 is a broadcast address. Vigor2910 will just accept the RIPv2 information with destination 18.104.22.168.