Please see sketch attached.
Imagine this is a midsize company that wants to provide full redundancy at Core, Distribution and Access Layer.
Between the two Cisco rotuers 2811A and 2811B, there is no need to have a physical connection there between the two, right? I hope not because there is no Ehternet interfaces available.
Someone suggested HSRP between the two routers... but if they are running OSPF (to handle internal routing) and BGP with service provider, I thought about setting up iBGP between the two.