T1 Load Balancing

I have a Cisco 2610 with one Full T and one half T.  Both with different IP spaces from the ISP.  (Could they have the same IP space?)  How could the load balancing be done with a full and a fractional T?
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JFrederick29Connect With a Mentor Commented:
It will simply send the packets round robin with no regard to network status.  If you are experiencing congestion on the fractional T1, yes, latency will be higher for those packets.  Ideally, you want to have equal size links.

If you want to simply use the fractional T1 for backup purposes only, use the same two default routes but add a higher administrative distance to the fractional T1 route:

ip route 68.x.x.1       <--- Full T1 (preferred route)
ip route 68.x.x.2 10  <--- Fractional T1 (backup route)
As long as it's the same ISP, you can use two equal cost default routes to your provider.

ip route 68.x.x.1
ip route 68.x.x.2

This will essentially load balance between the two T1's.
GentooOSAuthor Commented:
But one is only a fractional T.  Doesn't that matter?
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No, it doesn't matter with static routes.  One link will be faster than the other, thats all.  If you were running a routing protocol with your ISP, it would matter as the full T1 would be used first, the second would be used as a backup link, unless you manipulated the route cost.
GentooOSAuthor Commented:
If one packet is sent to each T, the frac T will "run out" of bandwidth first but packet will still be sent to that T, correct?
lrmooreConnect With a Mentor Commented:
If you want some load-sharing, enable CEF. The default load-sharing behavior is for per-connection instead of per-packet.

See more discussion here:
cmsJustinConnect With a Mentor Commented:
CEF is defiantly the way to go. You will need to configure it on your router as well as call your ISP and have them set it up on their end. Their will be a momentary loss of service while they cofigure it. You get both lines out and one line in, and the one line in depends on the IP address used.
I think that points should be split between:


Both methods would work, and are equally valid answers.

Very gracious Justin but I think it should be split 3 ways between:


We all contributed to the answer and had good information.
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