I have three Cisco IOS routers at three branch offices which are linked to each other through VPN tunnels. Each branch office has its own internet connection and uses this internet connection for general internet access.

The router in the first branch has an additional VPN tunnel to the corporate network. There are about a dozen static routes set up in the first router, routing various IP subnets through the VPN tunnel to the corporate network.

The second and third router use their VPN connection to the first router to access the corporate network from there. For this, the second and third router basically have the same static routes as the first router, forwarding all corporate network traffic to the first router which forwards it to the corporate network.

All this works fine but is a little cumbersome to maintain. Each time the static routes to the corporate network change it has to be done all all through routers.

I was thinking that it may be better to utilize a dynamic routing protocol instead which automatically propagates the static routes on the first router to the second and third. I have never done this before and the choice of protocols in the IOS documentation is big. From what I understand so far RIP or OSPF may be an option to achieve it. But lacking the experience with these protocols I wonder whether someone could make recommendation which protocol (if any) would be appropriate and maybe give an idea how to set it up.