Known issues of cisco ospf euqal cost load balancing

Unanswered Question
Sep 25th, 2008

Can I know what are the disadvantages of using cisco equal cost load balancing?

I have this problem too.
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Overall Rating: 3.3 (5 ratings)
Marwan ALshawi Fri, 09/26/2008 - 01:35

sometimes make problems with VOIP as it make delay variation known as jitter

if helpful Rate


Marwan is right and in addition, when you load balance, especialy per packet load balancing, packets are sent across the number of paths you have. if for any reason one link is faster than the other, then the packets arrive at the destination at different times and not necesarily in the same order they were sent. leading to the destination to receive out of sync packets and needing to re-order them.

use with caution in environments with jitter (varying delay) sensitive application like VOIP.


Giuseppe Larosa Fri, 09/26/2008 - 02:57

Hello Chris,

the disadvantages of per packet load-sharing for VoIP have been well described by Akin and Marwin.

When using per destination load-balancing or CEF based load-balancing ( SA IP exor dest IP) balancing is effective only when many flows exist.

If only one flow of few flows with high traffic volume are present you can have one link full and the other(s) empty.

Hope to help


Joseph W. Doherty Sun, 09/28/2008 - 12:04

Besides what's already been noted in the other posts, with any multi-path routing, including equal cost, you can sometimes bump into "stateful" issues caused by asymetrical routing.


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