[asterisk-users] Question about how Asterisk works with RTP ports

[Joshua Colp]

Jonas Kellens wrote:
> Hello,
>
> short question : does Asterisk reserve RTP ports for every IP-phone that
> is being called ?

It uses 2 ports per channel under normal circumstances, 1 for RTP and 1 
for RTCP.

> If for instance an incoming call makes 10 IP-phones ring, does this mean
> that Asterisk preserves 10 x 2 RTP ports for audio ?

Yes.

> I guess Asterisk sends in the SIP INVITE an SDP body with an RTP port
> number for audio ? If this is the case for the 10 IP-phones to which an
> INVITE is send to, this means at least 10 RTP ports are reserved for
> incoming audio, correct ???

Yes.

-- 
Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at:  www.digium.com  & www.asterisk.org