RFC 3313 (rfc3313) - Page 2 of 16

Private Session Initiation Protocol (SIP) Extensions for Media Authorization

RFC 3313         SIP Extensions for Media Authorization     January 2003


Table of Contents

   1. Scope of Applicability.........................................  2
   2. Conventions Used in this Document..............................  3
   3. Background and Motivation......................................  3
   4. Overview.......................................................  4
   5. Changes to SIP to Support Media Authorization..................  4
      5.1 SIP Header Extension.......................................  5
      5.2 SIP Procedures.............................................  5
        5.2.1 User Agent Client (UAC)................................  6
        5.2.2 User Agent Server (UAS)................................  6
        5.2.3 Originating Proxy (OP).................................  7
        5.2.4 Destination Proxy (DP).................................  7
   6. Examples.......................................................  8
      6.1 Requesting Bandwidth via RSVP Messaging....................  8
        6.1.1 User Agent Client Side.................................  8
        6.1.2 User Agent Server Side................................. 10
   7. Advantages of the Proposed Approach............................ 12
   8. Security Considerations........................................ 13
   9. IANA Considerations............................................ 13
   10. Notice Regarding Intellectual Property Rights................. 13
   11. Normative References.......................................... 14
   12. Informative References........................................ 14
   13. Contributors.................................................. 15
   14. Acknowledgments............................................... 15
   15. Editor's Address.............................................. 15
   16. Full Copyright Statement...................................... 16

1. Scope of Applicability

   This document defines a SIP extension that can be used to integrate
   QoS admission control with call signaling and help guard against
   denial of service attacks.  The use of this extension is only
   applicable in administrative domains, or among federations of
   administrative domains with previously agreed-upon policies, where
   both the SIP proxy authorizing the QoS, and the policy control of the
   underlying network providing the QoS, belong to that administrative
   domain or federation of domains.  Furthermore, the mechanism is
   generally incompatible with end-to-end encryption of message bodies
   that describe media sessions.

   This is in contrast with general Internet principles, which separate
   data transport from applications.  Thus, the solution described in
   this document is not applicable to the Internet at large.  Despite
   these limitations, there are sufficiently useful specialized
   deployments that meet the assumptions described above, and can accept
   the limitations that result, to warrant informational publication of
   this mechanism.  An example deployment would be a closed network,



Marshall, Ed.                Informational