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.
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
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
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
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