routers

This is a little off topic but I find that this mailing list has people with
a broad knowledge base.. Not just linux.. :-) My boss wants to setup a
router with a second T1 for redundancy. We have one T1 backbone with two
class C's. The second T1 is just a backbone (no ip's assigned to us.)
First of all if the backbone (with the ip's) went down is there any way
traffic could still get to us on the other T1? As far as I know I would
have to call both T1 service providers to see if they could adjust
fall-through routing or something.. I guess for outward packet I could set
the router up for OSPF.. Any links or advice would be appreciated. You can
send responses to me directly so this topic doesn't have to stay on the list
if no one wants to read about it..

don@nis4u.com

Don