Network Working Group
Request for Comments: 5478
Category: Standards Track
J. Polk
Cisco Systems
March 2009

IANA Registration of New Session Initiation Protocol (SIP)

Resource-Priority Namespaces

Status of This Memo

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

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This document creates additional Session Initiation Protocol (SIP) Resource-Priority namespaces to meet the requirements of the US Defense Information Systems Agency, and places these namespaces in the IANA registry.

Table of Contents

   1. Introduction ....................................................2
      1.1. Conventions Used in This Document ..........................3
   2. New SIP Resource-Priority Namespaces Created ....................3
   3. IANA Considerations .............................................4
      3.1. IANA Resource-Priority Namespace Registration ..............4
      3.2. IANA Priority-Value Registrations ..........................6
   4. Security Considerations .........................................6
   5. Acknowledgments .................................................6
   6. Normative References ............................................6

1. Introduction

The US Defense Information Systems Agency (DISA) is rolling out their Session Initiation Protocol (SIP) based architecture at this time. This network will require more Resource-Priority namespaces than were defined, and IANA registered, in RFC 4412 [RFC4412]. The purpose of this document is to define these additional namespaces. Each will be preemptive in nature, as defined in RFC 4412, and will have the same 10 priority-values.

DISA has a requirement to be able to assign different Resource- Priority namespaces to differing groups of differing sizes throughout their networks. Examples of this may be

  • namespaces as large as each branch of service (Army, Navy, Air Force, Marines, Coast Guard)
  • namespaces for some departments within the government (for example, Homeland Security)
  • namespaces that are temporary assignments to individual units of varying sizes (from battle groups to patrol groups or platoons)

These temporary assignments might be combinations of smaller units involving several branches of service operating as one unit (say, one task force, which is separate than the branch of service), or a single commando unit requiring special treatment for a short period of time, making it appear separate from the branch of service they are from.

Providing DISA with a pool of namespaces for fine-grained assignment(s) allows them the flexibility they need for their mission requirements. One can imagine due to their sheer size and separation of purpose, they can easily utilize a significant number of namespaces within their networks. This is the reason for the assignment of so many new namespaces, which seems to deviate from guidance in RFC 4412 to have as few namespaces as possible.

This document makes no changes to SIP, it just adds IANA-registered namespaces for SIP's use within the Resource-Priority header framework.

1.1. Conventions Used in This Document

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

2. New SIP Resource-Priority Namespaces Created

The following 40 SIP namespaces are created by this document:

   dsn-000000      drsn-000000      rts-000000      crts-000000
   dsn-000001      drsn-000001      rts-000001      crts-000001
   dsn-000002      drsn-000002      rts-000002      crts-000002
   dsn-000003      drsn-000003      rts-000003      crts-000003
   dsn-000004      drsn-000004      rts-000004      crts-000004
   dsn-000005      drsn-000005      rts-000005      crts-000005
   dsn-000006      drsn-000006      rts-000006      crts-000006
   dsn-000007      drsn-000007      rts-000007      crts-000007
   dsn-000008      drsn-000008      rts-000008      crts-000008
   dsn-000009      drsn-000009      rts-000009      crts-000009

Each namespace listed above is wholly different. However, according to the rules within Section 8 of RFC 4412, one or more sets can be treated as if they are the same when they are configured as an aggregated grouping of namespaces.

These aggregates of two or more namespaces, that are to be considered equivalent during treatment, can be a set of any IANA registered namespaces, not just adjacent (i.e., consecutive) namespaces.

Each namespace listed above will have the same 10 priority levels:

      .0 (lowest priority)
      .9 (highest priority)

According to the rules established in RFC 4412 [RFC4412], priority- values have a relative order for preferential treatment, unless one or more consecutive groups of priority-values are to be considered equivalent (i.e., first-received, first treated).

The dash character ('-') is just like any other ASCII character within a namespace, and is not to be considered a delimiter in any official way within any namespace here. Other namespace definitions in the future could change this.

As stated in Section 9 of RFC 4412 [RFC4412] an IANA-registered namespace SHOULD NOT change the number, and MUST NOT change the relative priority order, of its assigned priority-values.

3. IANA Considerations

Abiding by the rules established within RFC 4412 [RFC4412], this is a Standards-Track document registering new namespaces, their associated priority-values, and intended algorithms.

3.1. IANA Resource-Priority Namespace Registration

Within the "Resource-Priority Namespaces" registry in the sip- parameters section of IANA, the following table lists the new namespaces registered by this document.

                        Intended     New warn-   New resp.
   Namespace   Levels   Algorithm      code        code     Reference
   ----------  ------  ------------  ---------   ---------  ---------
   dsn-000000    10     preemption      no          no      [RFC5478]
   dsn-000001    10     preemption      no          no      [RFC5478]
   dsn-000002    10     preemption      no          no      [RFC5478]
   dsn-000003    10     preemption      no          no      [RFC5478]
   dsn-000004    10     preemption      no          no      [RFC5478]
   dsn-000005    10     preemption      no          no      [RFC5478]
   dsn-000006    10     preemption      no          no      [RFC5478]
   dsn-000007    10     preemption      no          no      [RFC5478]
   dsn-000008    10     preemption      no          no      [RFC5478]
   dsn-000009    10     preemption      no          no      [RFC5478]
   drsn-000000   10     preemption      no          no      [RFC5478]
   drsn-000001   10     preemption      no          no      [RFC5478]
   drsn-000002   10     preemption      no          no      [RFC5478]
   drsn-000003   10     preemption      no          no      [RFC5478]
   drsn-000004   10     preemption      no          no      [RFC5478]
   drsn-000005   10     preemption      no          no      [RFC5478]
   drsn-000006   10     preemption      no          no      [RFC5478]
   drsn-000007   10     preemption      no          no      [RFC5478]
   drsn-000008   10     preemption      no          no      [RFC5478]
   drsn-000009   10     preemption      no          no      [RFC5478]
   rts-000000    10     preemption      no          no      [RFC5478]
   rts-000001    10     preemption      no          no      [RFC5478]
   rts-000002    10     preemption      no          no      [RFC5478]
   rts-000003    10     preemption      no          no      [RFC5478]
   rts-000004    10     preemption      no          no      [RFC5478]
   rts-000005    10     preemption      no          no      [RFC5478]
   rts-000006    10     preemption      no          no      [RFC5478]
   rts-000007    10     preemption      no          no      [RFC5478]
   rts-000008    10     preemption      no          no      [RFC5478]
   rts-000009    10     preemption      no          no      [RFC5478]
   crts-000000   10     preemption      no          no      [RFC5478]
   crts-000001   10     preemption      no          no      [RFC5478]
   crts-000002   10     preemption      no          no      [RFC5478]
   crts-000003   10     preemption      no          no      [RFC5478]
   crts-000004   10     preemption      no          no      [RFC5478]
   crts-000005   10     preemption      no          no      [RFC5478]
   crts-000006   10     preemption      no          no      [RFC5478]
   crts-000007   10     preemption      no          no      [RFC5478]
   crts-000008   10     preemption      no          no      [RFC5478]
   crts-000009   10     preemption      no          no      [RFC5478]

3.2. IANA Priority-Value Registrations

Within the "Resource-Priority Priority-values" registry in the sip-parameters section of IANA, the list of priority-values for each of the 40 newly created namespaces from Section 3.1 of this document, prioritized least to greatest, is registered by the following (replicated similar to the following format):

   Namespace: dsn-000000
   Reference: RFC5478 (this document)
   Priority-Values (least to greatest): "0", "1", "2", "3", "4", "5",
   "6", "7", "8", "9"

4. Security Considerations

This document has the same Security Considerations as RFC 4412.

5. Acknowledgments

To Jeff Hewett for his helpful guidance in this effort. Thanks to Janet Gunn, John Rosenberg, Joel Halpern, Michael Giniger, Henning Schulzrinne, Keith Drage, and Suresh Krishnan for their comments.

6. Normative References

   [RFC4412]  Schulzrinne, H. and J. Polk, "Communications Resource
              Priority for the Session Initiation Protocol (SIP)", RFC
              4412, February 2006.
   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

Author's Address

   James Polk
   3913 Treemont Circle
   Colleyville, Texas  76034
   Phone: +1-817-271-3552