PPP Multilink - Uneven Links? (full T1 / frac T1)

[rainman]

Hello,

I have used MLPPP many times in the past to aggregate bandwidth over the WAN, however on each occasion I was using bundles of multiple (1 through 8) full T1's.

I have a situation where I might need to do MLPPP over uneven T1's (1152k/s on T1 #1 and 128k on T1 #2) in an attempt to provide load-balancing and a form of redundancy. My other alternative is to create two P2P WAN connections then do floating static routes, but I'd rather do MLPPP if possible.

Has anybody ever done MLPPP w/ uneven links? If so how did it work out?

Tx - Rainman

 

[baddos]

I don't think it's possible to do MLPP without decreasing your bandwidth. You might be able to do some weighted loadbalancing w/ EIGRP, but I don't think it's work the effort for an extra 128k.

You might be able to do some policy routing too, buy saying outbound HTTP requests go down the 128k link, but everything else goes down the other.

What I would probably do is add another lower cost default route for the second 128k T1, so the 1152k T1 has priority. The 128k would only be used in cast the 1152k T1 goes down.

 

[rainman]

I realize that I won't get much load balancing with the 2nd 128k T1, however this is what a customer wants to do because their 1st T1 failed once before. They want a 2nd T1 for failover purposes. I also believe a 2nd P2P connection with 2 default routes would work fine, and on the ISP side I can configure floating static routes for any subnets we're routing across the T1. Just thought it'd be easier to do MLPPP and conserve some WAN IP addresses.

Since MLPPP pulls each interface into the bundle, does it really matter if the T1's are similar in speed? I would think I can have a full T1, 128k, 768, 512 and bundle all 4 of them together and I "should" get an aggregate of 2944Mb/s. Just wondering if anybody has done this before and was it successful / not.


Tx again, Rainman

 

[baddos]

If the customer is just looking for a backup T1, then I wouldn't worry about trying to loadbalance it. It's hard enough getting a good load balance on equal links.