1 Router, 2 Frame Relay Circuits - Redundancy?

[dfusion]

I am replacing some old Bay ARN routers with Cisco and will be adding an additional WAN circuit to provide redundancy. Here is the scenario:

I want to provide redundancy from one WAN site to another. Location 1 will have a 2620 router with two WIC1-DSU cards and Location 2 will have a 2620 router with two WIC1-DSU cards. The first WIC on each will be an AT&T frame relay circuit and the second WIC on each will be a Qwest frame relay circuit. I want the AT&T to be primary and the Qwest to be secondary. How would I configure this within the router? I have never configured this before with a single router - only using two routers and HSRP for a virtual Ethernet address for the hosts.

Thank you!

Regards,
Mark


Sr. Network Engineer
ArcLight Systems, LLC

http://www.markholloway.com

 

[ewiley]

EIGRP is designed for this situation. If the circuits are of equal bandwidth, and they're permanent connections (i.e. no pay-per-bandwidth), then eigrp will loadbalance the connections automatically, assuming it's setup on both routers. If they are unequal sizes, but permanent connections, eigrp can do unequal load-balance using the &quot;variance <multiplier>&quot; command. Finally if you only want a hot-standby failover, you can either use floating static routes (not so good) or eigrp will do it for you if you set &quot;maximum-paths 1&quot; and change the bandwidth of the backup interface to be lower than the primary (so it's more desirable, and eigrp selects it for a route in the routing table).

Hope this helps.

 

[chrisjohnson4]

I agree with you ewiley, adding EIRGP will work well for this configuration, you can also research and maybe consider item A and B, below. I make these suggestions only because I have experienced problems with letting EIGRP determine the best routes for multiple paths or redundant paths of equal bandwidth.

What I have opted to do is this (I have always used item A):

A. Decrease the bandwith by one are two (secondary path), so that when required eigrp will distinctively avoid that low path and only select the primary path (the one that you leave with higher bandwidth)

OR

B. You can consider changing the administrative values

Good luck!

 

[kubley]

Assuming EIGRP is your routing protocol I completely agree with chrisjohnson4: Decrease the bandwidth on your secondary (backup)path.

EIGRP is not as &quot;smart&quot; as people think it is.