:[cisco-voip] Cisco phone protocol satellite

Fretz, EA Eric at IS Eric.A.Fretz at L-3com.com
Fri Feb 24 14:37:36 EST 2006


The codec itself is not as important as the sample period of the codec.  All
things being equal, if G.711 sounds better than G.729 over a LAN, the same
will be true over satellite, just more delay.  
 
The best thing you can do is try to increase the sample size so more of your
data is payload and not Layer2/Layer3 headers.  Simply increasing your
sample rate from 30ms to 60ms cuts your packetization rate in half, which
will in turn, reduce the amount of bandwidth required to maintain the RTP
stream.  It also depends on the type of satellite technology you are using.
If you are going up over Inmarsat, and you are getting a dedicated ISDN 64k
B-channel.  Therefore, your chances of packet loss are far less than some
other packet-switched based systems.   It's all relative.  
 
 

-----Original Message-----
From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Bob A. Bowie
Sent: Thursday, February 23, 2006 8:57 PM
To: cisco-voip at puck.nether.net
Subject: s::[cisco-voip] Cisco phone protocol satellite


Which protocol, G.711 or G.729 would be best for usage on a satellite
connection with close to
1 second round trip delay.  Would the G.711 be more resilent to lost
packets, when a packet is 
lost I lose more info on the G.729?

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