Redundant Routers - Suggestions Needed
Posted on 2005-04-23
I'm shopping around for bandwidth and have decided to go with two - two bonded T1's. I'm thinking with the cutover though, it might be a good time to look at our router setup - since I've just inherited this funky network. Right now we have one Cisco 3660 running BGP to two different ISP's through two T1's. I was thinking of maxing out a couple of 2851's and using them in a redundant setup. What I'm struggling to understand is how the two router's would provide redundancy. I've been researching HSRP, but don't think it does what I'm looking for.
| ----ISP A T1
PIX ---- Outside Switch 3500XL ---- 3660-
|----ISP B T1
|- 2851 ===== 2 T1's Bonded - ISP A
PIX ---- Outside Switch 3500XL -
|- 2851 ===== 2 T1's Bonded - ISP B
I guess my first question is, is it possible to have two pairs of cables plugged into both routers? I mean, if ISP A provides two T1's and I use MLPPP to configure it, and I do the same for ISP B into the same router, how to I get four more WAN links to the other router - without paying for four more T1's? I know this isn't the clearest way to put it and I apologize!
If that can't be done, then this question comes up:
If run one ISP into one router and the other ISP into the other router, is there a method that will let me utilize both router's bandwidth, but still allow me to occasionally bring one down for maintenance? I'm not concerned with losing half my bandwidth during this maintenance period...I just want to make sure that the devices understand one router is down and should pass all traffic through the active router.