RE: VoIP on ATM

From: Duane Dewitt (Duane.Dewitt@za.verizonbusiness.com)
Date: Tue Aug 15 2006 - 04:17:32 ART


Thanks for the feedback. Things start to look a lot worse when you add
V3PN into the picture. Then you require 3 cells and 64Kbps per call.

Regards
Duane

________________________________

From: Elias Chari [mailto:elias.chari@gmail.com]
Sent: 15 August 2006 09:14 AM
To: Duane Dewitt
Cc: ccielab@groupstudy.com
Subject: Re: VoIP on ATM

Hi,

You are right, two sells will be required per voip packet with a total
bandwidth per call of 44.5kb/s. Needeles to say that a fair bit of b/w
will be wasted due to the fact that you need 2 cells per voip packet and
of course the atm overhead.

I haven't done the calculations but with RTP header compression you may
go down to 1 cell per voip packet which will reduce your overheads
considerably.

Rgds
Elias

On 8/15/06, Duane Dewitt <Duane.Dewitt@za.verizonbusiness.com> wrote:

        Hi All

        I am trying to do a capacity forecast for G729 VoIP running on
ATM.

        My thinking is that the 60byte packet will have to be broken
into two
        cells. So instead of having 50 packets a second at 60bytes
(24Kbps) I
        need 50 packets a second at 106bytes (42Kbps). This works out to
almost
        double that bandwidth.

        Is this logic correct or am I missing something?

        Regards
        Duane de Witt
        Technical Sales Consultant
        CCIE #15715
        --------------------------------------------
        Verizon Business SA
        Tel. 27 11 235 6543
        Cell. 27 83 445 2768



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