[c-nsp] VOIP Quality with Multilink PPP

[Jon Lewis]

On Wed, 6 Sep 2006, Greene, Patrick wrote:

> I am about to deploy a large MPLS network and have a number of CE
> locations receiving nxT1 with MLPP.  I am running the standard priority
> queuing for voice and CBWFQ underneath that.  I have heard there can be
> voice quality issues caused by physical disparities in the T1 circuits
> themselves creating excessive out-of-order packets.  I spoke to TAC

MLPPP handles reordering, so as far as the VOIP gear is concerned, there 
should be no out of order packets.  If there are noticable disparities in 
T1 latencies within a ML group, then I suspect you would only see that as 
increased jitter.

Another possible issue to worry about is MLPPP does not CEF switch tagged 
packets until at least 12.3 on the 7200 platform.  I'm not sure about 
others.  So, if you're doing MPLS over MLPPP, and running say 12.2S (or 
earlier code), you may have problems.

----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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