Steve Underwood wrote: > > Paul Lambert wrote: > > >"Not yet." implies that it is coming. > > > Look at the latency it causes, and you will see its not that useful. > > >I know it would help on Internet > >connections such as fixed wireless and cable modem where packet rate is > >an issue. 20ms translates to 50 packets/sec. > > > 30ms per block codec aren't bad. Going beyond that gets nasty. 2 x 20ms > blocks per packet about the most people will tolerate. >
2 x 20ms cuts the packet rate in half. That means a fixed wireless ISP could fit twice the calls on a single access point. > >I believe cable modem > >upstream packet rates cap at 150-200 packets/sec. G729 gets the bit rate > >down to 8kbits. > > > G.729 gets the rate down to 8kbps. Then RTP puts it back up to several > times that. > > >So based on a bit rate of 256K the theory is that the > >link could handle 32 calls. But, that would produce packets coming out > >at a rate of 1600 packets/sec beyond the limitation of most Internet > >connections including a T1. > > > > > A T1 has no particular packet limit. It is just limited to 1544kbps. > Some routers choke on large numbers of small packets, but that is not a > T1 problem. There has to be a limit. You can't send 1 bit packets. As I think about it more, I'm sure it's higher than 1600 packets/sec probably closer to 3000 packets/sec. So with 20ms blocks/packet your limit on a T1 with IP would be 60 calls. Go 2 x 20ms and then you get 120 calls all with the same IP overhead. I think an extra 20ms latency could be worth it. > > Regards, > Steve > > _______________________________________________ > Asterisk-Users mailing list > [EMAIL PROTECTED] > http://lists.digium.com/mailman/listinfo/asterisk-users _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users
