This document specifies the Content-ID header field for
usage in the Session Initiation Protocol (SIP) to identify
a complete message-body of a SIP message. The document also
updates RFC 5621, to enable a Content-ID URL to reference
a complete message-body and metadata provided by some
additional SIP header fields.
Working Group Summary
Discussions about the Content-ID header field started in the
ECRIT working group when the group identified cases where a
request with a single message body also needs to include a
Content-ID header field in the SIP message header to refer to
the MIME entity, but the Content-ID header field was not actually
a SIP header field, surprising some working group members. The
authors brought the issue to the SIPCORE working group. There
was consensus that this was an oversight in SIP. There was a
discussion about perhaps adding all the Content-* MIME header
fields as SIP header fields for completeness (SIP already has
extended the some of the MIME header fields), but the working
group decided to focus only on Content-ID since there wasn't a
clear need for some of the others like Content-Transfer-Encoding.
This short document received detailed review from a handful
of working group participants. The authors incorporated received
Although the Document Shepherd is not aware of implementations,
the Content-ID header field will be useful when transporting
data for location conveyance and emergency calls. There may be
implementations of Content-ID as a SIP header field since
RFC 5368 shows Content-ID as a SIP header field in its examples.
Jean Mahoney is the document shepherd. Ben Campbell is
the responsible area director.