SALUD L. Liess, Ed.
Internet-Draft R. Jesske
Updates: 3261 (if approved) Deutsche Telekom AG
Intended status: Standards Track A. Johnston
Expires: April 20, 2015 Avaya
October 17, 2014
URNs for the Alert-Info Header Field of the Session Initiation Protocol
The Session Initiation Protocol (SIP) supports the capability to
provide a reference to a specific rendering to be used by the UA as
an alerting signal (e.g., a ring tone or ringback tone) when the user
is alerted. This is done using the Alert-Info header field.
However, the reference (typically a URL) addresses only a specific
network resource with specific rendering properties. There is
currently no support for standard identifiers for describing the
semantics of the alerting situation or the characteristics of the
alerting signal, without being tied to a particular rendering. To
overcome these limitations and support new applications, a new family
of URNs for use in Alert-Info header fields (and situations with
similar requirements) is defined in this specification.
This document normatively updates RFC3261, which defines the Session
Initiation Protocol (SIP): It changes the usage of the Alert-Info
header field defined in RFC3261 by additionally allowing its use in
any non-100 provisional response to INVITE.This document also permits
proxies to add or remove an Alert-Info header field, and to add or
remove Alert-Info header field values.
Status of This Memo
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Liess, et al. Expires April 20, 2015 [Page 1]Internet-Draft Alert URNs October 2014
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 6
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Updates to RFC 3261 . . . . . . . . . . . . . . . . . . . . . 6
4.1. Allow Alert-Info in Provisional Responses . . . . . . . . 6
4.2. Proxies May Alter Alert-Info Header Fields . . . . . . . 7