Re: [Serusers] SIP call hold/unhold - sr-users

15 Dec 2005

Sending to the list as more people might be interested...

I read offer/answer RFC quite a long ago but as far as I remember
there is no limit in the parameters you can change in a new
offer/answer exchange.
According to this, UA1 can change the port and the media direccion in
the same offer/answer exchange.

Samuel.

2005/12/15, tcchan &lt;tikchoong.chan(a)redtone.com&gt;om>:
...
  Dear Samuel,

 Thanks you very much for your answer.

 I would like to consult you the following:

 normal call,

 UA1 ----- invite --port 30000-------> UA2

 UA2 <---------OK port 20000 ---------UA2

 UA1 hold the call,

 UA1 -----invite --port 30000(hold) ----> UA2

 UA1 <--------OK port 20000 -------------UA2

 UA1 unhold the call,

 UA1 ------invite -----port 30001 -------> UA2
 UA1 <----------OK port 20000 -----------UA2

 Noticed that when UA1 unhold the call, it uses a different port.
 Is UA1 SIP compliant.

 Thanks again and Regards,

 TC Chan

 On Wed, 2005-12-14 at 09:18 +0100, samuel wrote:
  UA is not SIP compliant. It must include the SDP
in the OK.

 Samuel.

 2005/12/14, tcchan &lt;tikchoong.chan(a)redtone.com&gt;om>:
  Dear All,

 I encountered a UA that behave as follow:

 UA1 call UA2

 UA1 ---- invite with SDP -----> UA2

 UA1 <------OK with SDP --------UA2

 UA1 hold the call,

 UA1 ------invite (hold)  ------>UA2
 UA1 <--------OK but not SDP ---UA2

 UA1 unhold the call

 UA1 ------invite ----------->UA2
 UA1 <-------OK but also no SDP---UA2

 I found that most ATA(UA) would attached a SDP when reply an OK whether
 the call is hold or unhold.  But there is one ATA that does not (UA2).

 I noticed that some ATA--Linksys (UA1) would send a BYE to UA2 if it
 receive a OK with no SDP in the hold case.

 My Question is :

 Is UA2 behave according to RFC?

 Would deeply appreciate if someone could let me know the answer as I
 always have trouble reading RFCs...

 Thanks fot any help available.

 Regards,

 TC Chan

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