27 May
2005
27 May
'05
6:28 p.m.
which goes back to the point ur looking at a 50-70K as a rule of
thumb...I just tell me users they need 128K to make it go nicely, on
that they should be able to surf and talk at the same time
iqbal
Jorge Crichigno 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:
the 5.3, 6.3K are really theoretical, i dont think
they include IP
overheads, I used media_sessions.phtml, and looked at the actual calls
per codec, and I dont think u can really get a good call without 50-70K,
also most bandwidth providers (at least here in the UK) are
asymmetrical, so even on a 128K, u could have problems.
Having said that I have done a nice call on xlite using ilbc on dial up.
Iqbal
Kofi Obiri-Yeboah wrote:
.
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
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