Subject: [Sip] "t=" in 200

From: Baniel Uri-CUB001 <[email-masked]>
Date: Wed, 1 Aug 2001 06:17:02 -0500

Is it allowed for a UAS to change the original value of the SDP "t=" field in its 200 response?

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From: Gonzalo Camarillo <[email-masked]>
Date: Thu, 02 Aug 2001 19:56:54 +0300

Hello,

> Is it allowed for a UAS to change the original value of the SDP "t=" field in its 200 response?

The t value is typically intended to be used for pre-arranged events.
That is, the evening news will be multicast from 9 pm thru 10 pm.

The SDP of an INVITE for an "ad-hoc" session typically contains t=0 0,
since there is no pre-established duraction for the session. When the
session is over, a BYE will be sent.

So, if you receive an INVITE for a pre-arrange session (for example, the
evening news from 9 thru 10), it means that the multicast (in this
example) will begin at 9 and finish at 10. If you answer with a
different t= value it just means that you will leave the multicast
session before or after it has finished, but it does not make any
difference.

So, to answer you question, t= is nothing that you negotiate. You can
send a BYE whenever you want, regardless of the t= value.

Regards,

Gonzalo

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