Just to add a few more details, Greger is right to point out the quality inferiority of G.723 compared to those of G711 and G729. In fact, in most VOIP deployments, in order to quarantee interoperability, a minimum bandwidth of 128K is specified. However to reach the wider "lower bandwidth areas" most service providers are opting for G.723 which uses either 5.3 or 6.3K. At this low bandwidth transmission needs, one could literally reach "dial up modem" equipped areas. in fact most VOIP phone hardware and software are begining to specify G.723 as their default codec. Note that until the direct media connection phase of a VOIP vall setup, wide bandwidth is not required. Also note that analogue phones have a maximim bandwidth need of 3K, hence even the low quality of G.723/5.3K, compared to the average analogue phone call, is superior -- Worrying Is Like Paying Interest On A Loan You Are Yet To Take Be Happy! Don't Worry, Quoting "Greger V. Teigre" <greger(a)teigre.com>om>:

the success or failure of VOIP is dependent on inter operability. While I agree that "free" is better than "pay", unfortunately, for now, one should deploy whatever codec is more popular. remember that the sdp protocol allows for codec negotiation. -- Worrying Is Like Paying Interest On A Loan You Are Yet To Take Be Happy! Don't Worry, Quoting Juha Heinanen <jh(a)tutpro.com>om>:

Ouch !! Juha Heinanen wrote:

Disagree two big providers Skype, and Vonage....I'll throw in a 3rd Net2phone, also, since when did they ever interoperate with anyone, at a primary level, let alone a codec level. VoIP will work if the VoIP providers interconnect with each other, the end points can take care of the codec negotiation, I guess it adds overhead, but the more the merrier I think, and if its "free" the better it will be, rather than the likes of cisco locking all development down to one or the other, and hiking up prices. From a commercial point of view, all consumers want awesome quality and cheap prices, the internet has given them this notion that everything should be a $/£10 per month. If you have that, and they want the hardware subsidised, then when u have paid for codecs inserted, the business model just does not work, unless you have volumes. Vonage spends approx $110 in acquiring a customer, and it is a loss leader for them, but how many companies including those on this list have a cash corpus of $200+ million...if they do my services are for hire :-). They may not care of the cost of a codec....but I need to If a really good codec for low bandwidth hits the market it can only work if it is free...why? simply low bandwidth is currently deployed in places where internet penertration is low...due to policy or cost , and hence adding a further additonal cost onto the hardware, will not help it spread. So keep it free, and I know some of the guys on this list....and others like it, will make it all work together :-) Just my $0.02 Iqbal Kofi Obiri-Yeboah wrote:

I think the data rates with overhead are as follow: ---------------------------------------------------------------- iLBC - 30 ms (a packet each 30 ms) RTP payload: 50 bytes --> Rate: 13.3 Kbps RTP: 62 bytes UDP: 70 bytes IP: 90 bytes --> total rate: 24 Kbps ------------------------------------------------------------------- iLBC - 20 ms (a packet each 20 ms) RTP payload: 38 bytes --> Rate: 15.2 Kbps RTP: 50 bytes UDP: 58 bytes IP: 78 bytes --> total rate: 31.2 Kbps ------------------------------------------------------------------- G.729 - 2 voice frame per packet RTP payload: 20 bytes --> Rate: 8 Kbps RTP: 32 bytes UDP: 40 bytes IP: 60 bytes --> Total rate: 24 Kbps ------------------------------------------------------------------- G.729 - 4 voice frame per packet RTP payload: 40 bytes --> Rate: 8 Kbps RTP: 52 bytes UDP: 60 bytes IP: 80 bytes --> Total rate: 16 Kbps ------------------------------------------------------------------- G.711 - 20 ms (a packet each 20 ms) RTP payload: 160 bytes --> Rate: 64 Kbps RTP: 172 bytes UDP: 180 bytes IP: 200 bytes --> Total rate: 80 Kbps El vie, 27-05-2005 a las 10:36, Iqbal escribió:

In the following link there is a comparison between some codecs http://www.speex.org/comparison.html 723: primary advantage is very low bandwidth requirements -- Worrying Is Like Paying Interest On A Loan You Are Yet To Take Be Happy! Don't Worry, Quoting "info(a)beeplove.com" <info(a)beeplove.com>om>:

Yes, iLBC has the following variants: ------------------------------------------------------------------- iLBC - 30 ms (one packet each 30 ms) RTP payload: 50 bytes --> Transmition rate: 13.3 Kbps RTP: 62 bytes UDP: 70 bytes IP: 90 bytes --> Transmition rate: 24 Kbps ------------------------------------------------------------------- iLBC - 20 ms (one packet each 20 ms) RTP payload: 38 bytes --> Transmition rate: 15.2 Kbps RTP: 50 bytes UDP: 58 bytes IP: 78 bytes --> Transmition rate: 31.2 Kbps ------------------------------------------------------------------- El vie, 27-05-2005 a las 09:45, Juha Heinanen escribió: