[asterisk-dev] why 4 UDP ports per SIP call?

Russell Bryant russell at digium.com
Mon Nov 19 16:29:59 CST 2007

Olle E Johansson wrote:
>> Analyzing Asterisk I see 4 new UPD sockets opened by Asterisk per
>> incoming SIP call. I would assume RTP+RTCP=2, but why are there 4  
>> ports
>> opened?
> Have you enabled video at all?

Also, I apologize if you have already considered this, but for each call, is
there an outbound SIP channel as well?  In that case, it would be RTP/RTCP for
both the inbound and outbound channel.

Russell Bryant
Senior Software Engineer
Open Source Team Lead
Digium, Inc.

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