Internet Engineering Task Force (IETF)
Request for Comments: 6878
Updates: 3261
Category: Standards Track
ISSN: 2070-1721
A.B. Roach
March 2013

IANA Registry for the Session Initiation Protocol (SIP)

"Priority" Header Field


This document defines a new IANA registry to keep track of the values defined for the Session Initiation Protocol (SIP) "Priority" header field. It updates RFC 3261.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at

Copyright Notice

Copyright © 2013 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents ( in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

1. Introduction

This document defines a new IANA registry to keep track of the values defined for the Session Initiation Protocol (SIP) "Priority" header field. This header field was defined in [RFC3261], Section 20.26. It was clearly specified in a way that allows for the creation of new values beyond those originally specified; however, no registry has been established for it.

2. IANA Considerations

This document adds a new sub-registry, "Priority Header Field Values", to the "Session Initiation Protocol (SIP) Parameters" registry page. Its format and initial values are as shown in the following table:

                        | Priority   | Reference |
                        | non-urgent | RFC 3261  |
                        | normal     | RFC 3261  |
                        | urgent     | RFC 3261  |
                        | emergency  | RFC 3261  |

The policy for registration of values in this registry is "IETF Review" as that term is defined by [RFC5226]. This policy was chosen over lighter-weight policies due the potential architectural impact of the semantics associated with new values. Efforts contemplating adding a Priority value should consider whether the SIP Resource- Priority [RFC4412] or even a different protocol would be more appropriate for achieving their requirements.

3. Security Considerations

This document does not have any impact on the security of the SIP protocol. Its purpose is purely administrative in nature.

4. References

4.1. Normative References

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              June 2002.
   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

4.2. Informative References

   [RFC4412]  Schulzrinne, H. and J. Polk, "Communications Resource
              Priority for the Session Initiation Protocol (SIP)",
              RFC 4412, February 2006.

Author's Address

Adam Roach
Dallas, TX