[SIPForum-discussion] confussion about use of tcp/udp

[Neill Wilkinsonj]

RTP (voice) is always carried over UDP. There is one notable exception and I
believe Skype can sometimes use TCP to carry voice. TCP generally has some
undesirable properties (Head-of-Line blocking and long timers related to
connection state), which make it unsuitable for carry realtime traffic such
as voice.

 

SIP signalling can travel over UDP or TCP, generally the UA(C) will choose
one or the other at the start of the interaction and the UA(S) will respond
using the same for the complete dialogue. That is my observation in
Practice.

 

Someone else on the list more conversant with RFC which to confirm or
clarify?

 

 Neill....;o)

From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of khalikh uddin
Sent: 09 June 2008 07:18
To: discussion at sipforum.com
Cc: kranti kumar
Subject: [SIPForum-discussion] confussion about use of tcp/udp

 


hai all
can anybody tell me 
 *when a sip enabled end device opens a TCP connection and when it uses UDP
to send *REQ/RESPONSES to proxy or other UA.
*can it use both in a  aparticular diloge i.e to send INVITE use TCP and to
send ACK use       
  UDP.
*Can we force it to use TCP/UDP.
*For media transmission SIP uses only tcp.Is this true.




 

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