I am looking for an economical solution to compress 1248 voice DS-0s to 240 DS0s. My application is to extend the voice and data for a call center that needs roughly 63 T-1 equivalents of bandwidth down 21 physical T-1 ciscuits.
On Thu, 13 Nov 2003, Robert White wrote:
I am looking for an economical solution to compress 1248 voice DS-0s to 240 DS0s. My application is to extend the voice and data for a call center that needs roughly 63 T-1 equivalents of bandwidth down 21 physical T-1 ciscuits.
ECI Telecom Ltd. www.ecitele.com
<> Nathan Stratton nathan at robotics.net http://www.robotics.net
> I am looking for an economical solution to compress > 1248 voice DS-0s to 240 DS0s. My application is to > extend the voice and data for a call center that needs > roughly 63 T-1 equivalents of bandwidth down 21 > physical T-1 ciscuits. Um, do you mean that you need to move 1248 _simultaneous calls_ across 21 T1 circuits? There's no problem there, just pick any reasonable codec. All you need is one that uses less than 26kbps of bandwidth, and nearly all of them meet that criterion. Take a look at G.729a. It's widely used, gives reasonably good quality, and only takes half that much bandwidth. -Bill
Bill Woodcock said:
> I am looking for an economical solution to compress > 1248 voice DS-0s to 240 DS0s. My application is to > extend the voice and data for a call center that needs > roughly 63 T-1 equivalents of bandwidth down 21 > physical T-1 ciscuits.
[snip]
Take a look at G.729a. It's widely used, gives reasonably good quality, and only takes half that much bandwidth.
I would like to also suggest seeking devices that use "iLBC" as a codec. I've been using this codec for interconnecting voip systems and have been very pleased with the results. Check it out: http://www.ilbcfreeware.org
From the overview:
"Bitrate 13.33 kbps (399 bits, packetized in 50 bytes) for the frame size of 30 ms and 15.2 kbps (303 bits, packetized in 38 bytes) for the frame size of 20 ms Basic quality higher then G.729A, high robustness to packet loss Computational complexity in a range of G.729A Royalty Free Codec" --Tk
On Thu, 13 Nov 2003, Anton L. Kapela wrote: > I would like to also suggest seeking devices that use "iLBC" as a > codec. I've been using this codec for interconnecting voip systems and > have been very pleased with the results. > Check it out: http://www.ilbcfreeware.org Yep, although I haven't used it yet myself, I've been hearing it very widely praised, particularly for traffic flowing across high-congestion Internet links. Apparently it can sustain 20% packet loss without significant reduction in voice quality. However, this was supposed to be over "T1s" which I assumed to mean point-to-point serial. -Bill
There is also something out there called IAX trunking. It can use a low bandwidth codec and put a bunch of simultaneous conversations into fewer packets, which helps to cut down on the high packet tax you'd normally get with packetizing individual voice channels. And works over any IP link. Ray Burkholder ray@oneunified.net http://www.oneunified.net 704 576 5101
-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Bill Woodcock Sent: November 13, 2003 21:10 To: Anton L. Kapela Cc: Robert White; nanog@merit.edu Subject: Re: Voice Compression
On Thu, 13 Nov 2003, Anton L. Kapela wrote: > I would like to also suggest seeking devices that use "iLBC" as a > codec. I've been using this codec for interconnecting voip systems and > have been very pleased with the results. > Check it out: http://www.ilbcfreeware.org
Yep, although I haven't used it yet myself, I've been hearing it very widely praised, particularly for traffic flowing across high-congestion Internet links. Apparently it can sustain 20% packet loss without significant reduction in voice quality. However, this was supposed to be over "T1s" which I assumed to mean point-to-point serial.
-Bill
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g729 Has pretty "Decent" voice Quality. Each Call is 8k Compressed. G728 is 16k Compressed. Now, these values do not take into account IP Header overhead. VoIP Equipment for 51 DS1's is not going to be cheap. The best bet on the Cisco Side is the 6500 or even a router like the 7200 the with the Voice Card's. Again, not cheap, but it does work pretty well.. Spencer ************************************************************ Spencer Wood, Network Manager Ohio Department Of Transportation 1320 Arthur E. Adams Drive Columbus, Ohio 43221 E-Mail: Spencer.Wood@dot.state.oh.us Phone: 614.644.5422/Fax: 614.887.4021/Pager: 866.591.9954 ************************************************************* Robert White <texan37@swbell.net> Sent by: owner-nanog@merit.edu 11/13/2003 03:18 PM To nanog@merit.edu cc Subject Voice Compression I am looking for an economical solution to compress 1248 voice DS-0s to 240 DS0s. My application is to extend the voice and data for a call center that needs roughly 63 T-1 equivalents of bandwidth down 21 physical T-1 ciscuits.
participants (6)
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Anton L. Kapela -
Bill Woodcock -
Nathan Allen Stratton -
Ray Burkholder -
Robert White -
Spencer Wood