[Nanog] VoIP over Asymmetric routing

endzer endzer at verizon.net
Mon Apr 21 11:54:31 UTC 2008


In _Theory_ asymmetric routing _should_ be ok, but that's in theory.

I would be concerned as to why they are designing it this way. Have they
gave you a good technical reason it has to be this way? I would ask them to
justify it.

Also, if there are routing problems on one path but not the other, this
could cause a scenario where voice is heard but not received, or vice-versa.
This situation is much more frustrating to customers as they will try and
continue the conversation. Opposed to if it just doesn't work at all because
of a routing problem, customer will just use their cell phones.

Also, are they implementing any local PSTN access for local calls or

That's my experiences.

-----Original Message-----
From: Kim Onnel [mailto:karim.adel at gmail.com] 
Sent: Monday, April 21, 2008 2:35 AM
To: NANOG list
Subject: [Nanog] VoIP over Asymmetric routing


We are going to roll out a network to carry VoIP only, between the P
routers, there will be 3xOC3 links.

Each site has 2xPEs, PE1 is connected to the P router in the local premises
with 10GE and PE2 is connected with 2xOC3s to remote P sites for backup
incase local P fails.

VoIP is going to be generated by Ericsson Media Gateways and the network
designers are suggesting to take traffic in the outgoing direction through
the PE1 path and come back through the PE2 path (if that makes sense), so
traffic will take a different link for outgoing over incoming.

>From your experiences, I am wondering what are future unforeseen pitfalls
can get into?

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