IANA Registration of New Session Initiation Protocol (SIP) Resource-Priority Namespace for Mission Critical Push To Talk Service
Two new SIP priority namespaces, mcpttp and mcpttq, registered so Mission Critical Push To Talk calls can be prioritized.
Holmberg, C. and J. Axell, "IANA Registration of New Session Initiation Protocol (SIP) Resource-Priority Namespace for Mission Critical Push To Talk Service", RFC 8101, DOI 10.17487/RFC8101, March 2017, <https://www.rfc-editor.org/info/rfc8101>.
@misc{rfc8101,
series = {Request for Comments},
number = 8101,
howpublished = {RFC 8101},
publisher = {RFC Editor},
doi = {10.17487/RFC8101},
url = {https://www.rfc-editor.org/info/rfc8101},
author = {C. Holmberg and J. Axell},
title = {{IANA Registration of New Session Initiation Protocol (SIP) Resource-Priority Namespace for Mission Critical Push To Talk Service}},
pagetotal = 6,
year = 2017,
month = mar,
} RFC text
Contents
Internet Engineering Task Force (IETF) C. Holmberg
Request for Comments: 8101 J. Axell
Category: Informational Ericsson
ISSN: 2070-1721 March 2017
IANA Registration of New Session Initiation Protocol (SIP)
Resource-Priority Namespace for Mission Critical Push To Talk Service
Abstract
This document creates additional Session Initiation Protocol (SIP)
Resource-Priority namespaces to meet the requirements of the
3GPP-defined Mission Critical Push To Talk (MCPTT) and places these
namespaces in the corresponding IANA registry.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc8101.
Copyright Notice
Copyright (c) 2017 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
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 3
3. New SIP Resource-Priority Namespaces Created . . . . . . . . 3
3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 3
3.2. The MCPTT Namespaces . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Normative References . . . . . . . . . . . . . . . . . . . . 5
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
The Third Generation Partnership Project (3GPP) has defined a Mission
Critical Push To Talk (MCPTT) over LTE service [TS.3GPP.22.179]. The
MCPTT service supports an enhanced Push To Talk (PTT) service that is
suitable for mission critical scenarios and is based upon 3GPP
Evolved Packet System (EPS) services. The requirements for the MCPTT
service defined within 3GPP can also form the basis for other PTT
services.
The MCPTT service is intended to support communication between
several users (a group call), where each user can gain permission to
talk in an arbitrated manner. However, the MCPTT service also
supports private calls between pairs of users.
MCPTT is primarily targeted to provide a professional PTT service to,
e.g., public safety, transport companies, utilities, and industrial
and nuclear plants. In addition to this, a commercial PTT service
for non-professional use (e.g., groups of people on holiday) may be
delivered through an MCPTT system. Based on their operational model,
the performance and MCPTT features in use vary per user organization,
where functionality that is more mission-critical-specific (e.g.,
Imminent Peril Call) might not be available to commercial customers.
The MCPTT service provides its users with different priorities for
the access to network resources in order to provide means to
prioritize between calls when resources are scarce. Among other
things, these priorities take into account the priority and role of
the caller, the priority and type of the group, and the situation in
which the call is made.
The SIP-level call control procedures using these namespaces are
specified in [TS.3GPP.24.379]. The namespaces defined here will
support a wide range of queuing options. The namespaces correspond
to what can be supported over the 3GPP Rx interface, defined in
[TS.3GPP.29.214]. The usage of the namespaces can be tailored to the
needs of the operator. The mechanism to do this is to configure
which values a specific user is allowed to use. This configuration
is specified in [TS.3GPP.24.384].
High-priority calls (when the life of either a public safety worker
or anyone else is in danger) need to be set up immediately; thus,
they require preemption. Other calls may be less sensitive in call
setup time but have a high priority once established. For these
calls, a queueing mechanism is more appropriate. The MCPTT data
transfer service currently under development can benefit from a
queueing mechanism. Another example is video-only calls that are not
critical in call setup time but where keeping the call is important.
This document creates additional SIP Resource-Priority namespaces to
meet the requirements of the 3GPP-defined MCPTT and places these
namespaces in the IANA registry.
2. Applicability
This document defines namespaces applicable for MCPTT services
defined by 3GPP that use the network services of a 3GPP-defined LTE
network. The use of this namespace outside such networks is
undefined.
3. New SIP Resource-Priority Namespaces Created
3.1. Introduction
This document introduces the following MCPTT namespaces: mcpttp and
mcpttq. The names of which come from the 3GPP-defined MCPTT service.
3.2. The MCPTT Namespaces
The mcpttp namespace uses the priority levels listed below from
lowest to highest priority.
mcpttp.0 (lowest priority)
mcpttp.1
mcpttp.2
mcpttp.3
mcpttp.4
mcpttp.5
mcpttp.6
mcpttp.7
mcpttp.8
mcpttp.9
mcpttp.10
mcpttp.11
mcpttp.12
mcpttp.13
mcpttp.14
mcpttp.15 (highest priority)
The Namespace Numerical Value is 46.
Intended algorithm for mcpttp is preemption.
New Warning code: No.
New SIP response code: No.
The mcpttq namespace uses the priority levels listed below from
lowest to highest priority.
mcpttq.0 (lowest priority)
mcpttq.1
mcpttq.2
mcpttq.3
mcpttq.4
mcpttq.5
mcpttq.6
mcpttq.7
mcpttq.8
mcpttq.9
mcpttq.10
mcpttq.11
mcpttq.12
mcpttq.13
mcpttq.14
mcpttq.15 (highest priority)
The Namespace Numerical Value is 47.
Intended algorithm for mcpttq is queuing.
New Warning code: No.
New SIP response code: No.
4. Security Considerations
This document does not have any impact on the security of the SIP
MCPTT protocol. Its purpose is purely administrative in nature.
5. IANA Considerations
Abiding by the rules established within [RFC4412] and [RFC7134], this
is an Informational RFC creating two new namespaces, their associated
priority-values, and intended algorithms.
6. Normative References
[RFC4412] Schulzrinne, H. and J. Polk, "Communications Resource
Priority for the Session Initiation Protocol (SIP)",
RFC 4412, DOI 10.17487/RFC4412, February 2006,
<http://www.rfc-editor.org/info/rfc4412>.
[RFC7134] Rosen, B., "The Management Policy of the Resource Priority
Header (RPH) Registry Changed to "IETF Review"", RFC 7134,
DOI 10.17487/RFC7134, March 2014,
<http://www.rfc-editor.org/info/rfc7134>.
[TS.3GPP.22.179]
3GPP, "3rd Generation Partnership Project; Technical
Specification Group Services and System Aspects; Mission
Critical Push To Talk (MCPTT) over LTE; Stage 1", 3GPP
TS 22.179 13.3.0, December 2015.
[TS.3GPP.29.214]
3GPP, "3rd Generation Partnership Project; Technical
Specification Group Core Network and Terminals; Policy and
Charging Control over Rx reference point;", 3GPP TS 29.214
13.7.0, September 2016.
[TS.3GPP.24.379]
3GPP, "3rd Generation Partnership Project; Technical
Specification Group Core Network and Terminals; Mission
Critical Push To Talk (MCPTT) call control; Protocol
specification;", 3GPP TS 24.379 13.2.0, September 2016.
[TS.3GPP.24.384]
3GPP, "3rd Generation Partnership Project; Technical
Specification Group Core Network and Terminals; Mission
Critical Push To Talk (MCPTT) configuration management;
Protocol specification", 3GPP TS 24.384 13.2.0, September
2016.
Acknowledgments
The authors would like to thank Bob Fredericks, Baruh Hason, Mary
Barnes, and Keith Drage for comments and discussions.
Authors' Addresses
Christer Holmberg
Ericsson
Hirsalantie 11
Jorvas 02420
Finland
Email: christer.holmberg@ericsson.com
Joergen Axell
Ericsson
Groenlandsgatan 31
Stockholm 16480
Sweden
Email: jorgen.axell@ericsson.com
AI ELI5
On this page
§1Introduction
The Third Generation Partnership Project (3GPP) has defined a Mission Critical Push To Talk (MCPTT) over LTE service. It supports group calls, where each user gains permission to talk in an arbitrated manner, and private calls between pairs of users. It targets professional users such as public safety, transport companies, utilities, and industrial and nuclear plants, and a commercial service may also be delivered through an MCPTT system.
MCPTT gives users different priorities for access to network resources so calls can be prioritized when resources are scarce. The priorities take into account the caller's priority and role, the group's priority and type, and the situation in which the call is made.
MCPTT is a walkie-talkie service over the phone network for people like emergency workers. When the network is crowded, important calls need to win.
§2Preemption and Queuing
High-priority calls, such as when the life of a public safety worker or anyone else is in danger, must be set up immediately, so they require preemption. Other calls may be less sensitive to setup time but have a high priority once established, so a queueing mechanism fits better. The RFC gives the MCPTT data transfer service and video-only calls as examples that can benefit from queueing.
This is why two namespaces are needed. The SIP-level call control procedures that use them are specified in 3GPP TS 24.379, and operators can tailor usage by configuring which values a given user may use.
An emergency call is like an ambulance that pushes ahead of traffic. A less urgent call is like waiting in a line, but once you are in, nobody should kick you out.
§3Applicability
The namespaces apply to MCPTT services defined by 3GPP that use the network services of a 3GPP-defined LTE network. The RFC states that use outside such networks is undefined.
The namespaces are also described as corresponding to what can be supported over the 3GPP Rx interface, and as supporting a wide range of queuing options.
These labels are made for one kind of phone network. Using them anywhere else is not covered.
§4The Two Namespaces
The mcpttp namespace has priority levels mcpttp.0 (lowest) through mcpttp.15 (highest). Its Namespace Numerical Value is 46 and its intended algorithm is preemption.
The mcpttq namespace has levels mcpttq.0 (lowest) through mcpttq.15 (highest). Its Namespace Numerical Value is 47 and its intended algorithm is queuing.
For both, the RFC says there is no new Warning code and no new SIP response code.
There are two ladders, each with steps from 0 to 15. Higher steps win. One ladder is for pushing ahead and the other is for waiting your turn.
| Namespace | Numerical value | Levels | Intended algorithm |
|---|---|---|---|
| mcpttp | 46 | mcpttp.0 (lowest) to mcpttp.15 (highest) | Preemption |
| mcpttq | 47 | mcpttq.0 (lowest) to mcpttq.15 (highest) | Queuing |
§5IANA and Security
Following the rules of RFC 4412 and RFC 7134, the RFC is an Informational RFC that creates two new namespaces, their priority values and their intended algorithms in the IANA registry.
On security, the RFC says it has no impact on the security of the SIP MCPTT protocol and that its purpose is purely administrative.
The RFC just writes the new labels into the official list. It does not change how safe anything is.