[Asterisk-Users] Adit 600 as VoIP router (MGCP) and Asterisk

[Peter Svensson]

On Fri, 21 Jan 2005, Daniel Nyström wrote:

> Do you think it's hearable? All communication will be on a dedicated
> Fast Ethernet link (just a cross-over cable). And it will still use aLaw
> codec (same as Euro ISDN afaik).

> Since E1 = 2048Kbps and FastEth = 100Mbps, I concidered it fast enough
> to not make any latency. It seems like MGCP also can use UDP. In that
> case, there won't be any retransmission or anything.

What you will notcie is the packetization delay of 20ms (or 30 depening on
the codecs) which yeilds 40-60ms round trip time possibly combined with
jitter buffers. The transmission time, once packetized is usually not very
significant, it is the packetization and possible user level queues that 
mess up the latency.

The delay on almost any voip technology can transform a nice sidetone to a 
nasty echo. This is one of many reasons telecom people strive to minimize 
latency.

> Do you have any experiences using MGCP of any kind?

Unfortunatly not. 

Peter