Practical limit of number links in a multilink bundle

Unanswered Question
Mar 26th, 2008

Is there any suggested practical limit on the number of links that should be used as part of multilink?

Any such information documented somewhere.

One of our client already has 9 T1 in a multilink bundle and wants to add more. I see a lot of reordered segments and fragment loss under the multilink which sometimes result in slow response etc..

Platform used is 38xx

Is it best to migrate to a DS3 (or a single fat pipe) when the bandwidth requirement reaches a certain limit?

Narayan

I have this problem too.
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guruprasadr Wed, 03/26/2008 - 03:06

HI Narayan, [Pls Rate if HELPS]

In our Network, the MAX Limit for MultiLink was able to handle is 8" E1 circuits bundled.

When i add the 9th E1 Circuit, we have experienced Packet Drops & Latency Delays.

In most cases, the CISCO address as IOS compatibility Issue for such problem.

I am not sure about T1" Limit for MultiLink bundle. Let me keep you updated if i get any.

Hope I am Informative.

Pls Rate if HELPS

Best Regards,

Guru Prasad R

Danilo Dy Wed, 03/26/2008 - 04:41

Hi,

Just remembered working on Frame Relay a long time ago and come across on this while trying to find a solution (when MPLS and MetroE is not available yet - T3 is very expensive for and old infra yet).

It depends on the platform. I can't find a document for 38xx but as what Guru said, 8 is the safe number.

Here are reference for higher end routers (they range from 8, 16, 32, and 40 interfaces) the IOS is 12.4 now http://www.cisco.com/en/US/docs/ios/12_4/wan/configuration/guide/hdmfr_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1037872

Try MPLS or MetroE. The cost depends in your location. I will not try old technology as their infra is old also :)

Regards,

Dandy

Joseph W. Doherty Wed, 03/26/2008 - 04:43

In theory, there shouldn't be much of a limit. In practice, I haven't worked with any MLP bundles (or IMA) with that many links. Usually, deciding factor is cost of DS3 (if available), possibly fractional or subrated, vs. individual DS1s.

If by seeing reordered segments, you mean a flow's packets no longer egress in sequence, I would be very concerned since MLP ought to preclude that.

royalblues Wed, 03/26/2008 - 05:00

Thanks guys for your inputs.

Even i think it is best to migrate to a fat link (or subrate DS3) once you cross about 8M anyway

The customer needs some evidence and i could not find any for the above platform

Cost is a very important factor as it would basically be a trans pacific link (India - US).

Narayan

shivlu jain Fri, 04/04/2008 - 07:38

I think that we can add upto 16 because cisco is having 16 hash algorithm

regards

shivlu

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