Subject: [Sip] Refer 3515 has a minor inconsistency

From: "Arunachalam Venkatraman \(arunvenk\)" <[email-masked]>
Date: Fri, 5 May 2006 08:51:00 -0700

2.4.6 Multiple REFER Requests in a Dialog

   A REFER creates an implicit subscription sharing the dialog
   identifiers in the REFER request.  If more than one REFER is issued
   in the same dialog (a second attempt at transferring a call for
   example), the dialog identifiers do not provide enough information to
   associate the resulting NOTIFYs with the proper REFER.

   Thus, for the second and subsequent REFER requests a UA receives in a
   given dialog, it MUST include an id parameter[2] in the Event header
   field of each NOTIFY containing the sequence number (the number from
   the CSeq header field value) of the REFER this NOTIFY is associated
   with.  This id parameter MAY be included in NOTIFYs to the first
   REFER a UA receives in a given dialog.  A SUBSCRIBE sent to refresh
   or terminate this subscription MUST contain this id parameter.

The last two paragraphs lead to the following conclusion -
The first REFER subscription in a dialog cannot be refreshed if the
transferee does not send an id in the INITIAL notify.

This does not seem reasonable and so I think the qualification "second
and subsequent" above must be replaced with "all".

It is a minor point and an unlikely use case. It could be logged as
such.

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