[*] [on-asterisk] 3CX and non Asterisk PBX users.

[John Lange]

Sorry to revive a stale thread but I've been doing some work recently
with the Cisco 9971 phone and interestingly this phone is TCP only for
both SIP and RTP.

Since Microsoft and Cisco are both doing VOIP TCP I'm curious if there
is actually a good reason for this or if it's just a case of the blind
leading the blind?

As I said previously in this thread, SIP TCP _might_ make some sense
as long as you stripped the state tracking out of the SIP protocol
(which means it wouldn't actually be SIP anymore) but RTP over TCP?
Madness!

I can think of only two reasons for this:

a) Microsoft doesn't know jack about SIP/RTP so they wrote it using
TCP because they didn't know any better & Cisco wanted to be
compatible with Microsoft.

b) Cisco firewalls aren't good at reliably tracking UDP state so they
decided to get around the problem by using TCP.

If there is actually a good technical reason for voip over TCP I'd
love to hear it.

-- 
John Lange
www.johnlange.ca