[SIPForum-discussion] INVITE request without SDP

[Garron, James]

Some devices require that DSP resource be reserved up (compression,
2833, etc) if SDP is sent in the initial INVITE, and some are not able
to de-allocate these resource after the fact.  So it is a way conserving
or more efficiently utilizing DSP resources, (I believe that Cisco may
do this).

 

 

________________________________

From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of Hasini Gunasinghe
Sent: Friday, March 13, 2009 5:46 AM
To: discussion at sipforum.org
Subject: [SIPForum-discussion] INVITE request without SDP

 

Hi All,

Could anyone please tell me what are the practical situations that a UA
(such as a SIP phone) wants to send an INVITE request with out SDP offer
in the body of the message?

Only scenario i can think of is: when clients want to know the far end
full list of media capabilities before they send their own offer. Is
there any other situations too?

Is it a must for a SIP phone application to have the ability of
initiating a call without SDP in the INVITE?

I tried to use the sip stack provided with RTC Client API, to send an
INVITE without SDP, but could not find a way to achieve that. If anyone
of you have been able to do that before please do let me know too.

Thank you.
regards,
Hasini. 

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