RFC 8101

RFC 8101 🎀 IANA Registration of New SIP Resource-Priority Namespaces for Mission Critical Push To Talk Service

Title block tea ☕

• Series: Internet Engineering Task Force (IETF)
• RFC number: 8101
• Title: IANA Registration of New Session Initiation Protocol (SIP) Resource-Priority Namespace for Mission Critical Push To Talk Service
• Authors: C. Holmberg and J. Axell, both from Ericsson 💜
• Category: Informational
• ISSN: 2070-1721
• Date: March 2017
• Obsoletes / Updates: the title block doesn't list anything this one obsoletes or updates ✨

Abstract

okay bestie, so this doc adds new SIP Resource-Priority namespaces 🦋 for the 3GPP-defined Mission Critical Push To Talk (MCPTT) service, and then slots them into the matching IANA registry. that's the whole mission 💅

Status of This Memo

ngl this part is the paperwork 📄 It says this document is not an Internet Standards Track specification. It's published for informational purposes only 🌸

It is still a product of the IETF, so it reflects the consensus of the IETF community. It got public review and was approved for publication by the Internet Engineering Steering Group (IESG). Not every IESG-approved doc is up for any level of Internet Standard, so check Section 2 of RFC 7841 if you're curious 🧐

If you want the current status, any errata, or a way to send feedback, head to 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) as they stood on the publication date. Please actually read those, because they spell out your rights and restrictions for this doc 🙈

Any Code Components pulled out of this document have to include the Simplified BSD License text, as described in Section 4.e of the Trust Legal Provisions. They come 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

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1. Introduction ✨

okay so the Third Generation Partnership Project (3GPP) defined a Mission Critical Push To Talk (MCPTT) over LTE service [TS.3GPP.22.179] 📡 It's an enhanced Push To Talk (PTT) service built for mission critical scenarios, and it runs on top of the 3GPP Evolved Packet System (EPS) services. The MCPTT requirements defined within 3GPP can also be the basis for other PTT services, which is lowkey iconic 👑

MCPTT is meant to support group calls, where each user can get permission to talk in an arbitrated way. It also supports private calls between pairs of users 🫶

It's mainly built as a professional PTT service for things like public safety, transport companies, utilities, and industrial and nuclear plants 🏭 BUT it can also be a commercial PTT service for non-professional use, like groups of people on holiday 🌴 Depending on how each user organization runs things, the performance and the MCPTT features in use can vary. Mission-critical-specific stuff, like the Imminent Peril Call, might not be available to commercial customers 🙈

MCPTT gives users different priorities for accessing network resources, so calls can be prioritized against each other when resources are scarce. These priorities take into account the priority and role of the caller, the priority and type of the group, and the situation the call is made in 💖

The SIP-level call control procedures that use these namespaces are specified in [TS.3GPP.24.379] 📞 The namespaces defined here support a wide range of queuing options, and they correspond to what can be supported over the 3GPP Rx interface, defined in [TS.3GPP.29.214] 🦋 Operators can tailor how the namespaces get used. The way to do that is to configure which values a specific user is allowed to use, and that configuration is specified in [TS.3GPP.24.384] 🔧

Now the vibe check: high-priority calls, where the life of either a public safety worker or anyone else is in danger, need to get set up immediately, so they need preemption 🚨 Other calls are less sensitive to setup time but still get high priority once they're established, so a queueing mechanism fits them better. The MCPTT data transfer service that's currently under development can benefit from queueing too. Video-only calls are another example. They aren't critical in setup time, but keeping the call alive matters a lot 🎥

This document creates additional SIP Resource-Priority namespaces to meet the requirements of the 3GPP-defined MCPTT, and it places those namespaces in the IANA registry 🌈

2. Applicability 🗺️

This doc defines namespaces that apply to 3GPP-defined MCPTT services running over the network services of a 3GPP-defined LTE network. Using these namespaces outside of such networks is undefined, so don't go there 🙅‍♀️

3. New SIP Resource-Priority Namespaces Created 🌸

3.1. Introduction

Two MCPTT namespaces get introduced here: mcpttp and mcpttq 🎀 Their names come from the 3GPP-defined MCPTT service, so that's where the name energy is from ✨

3.2. The MCPTT Namespaces

The mcpttp namespace uses the priority levels below, listed 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)

For mcpttp, the Namespace Numerical Value is 46 🔢 The intended algorithm for mcpttp is preemption ⚡ There is no new Warning code for it, and no new SIP response code either 🙅‍♀️

The mcpttq namespace uses the priority levels below, also 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)

For mcpttq, the Namespace Numerical Value is 47 💜 The intended algorithm for mcpttq is queuing 🫧 Same deal as before: no new Warning code and no new SIP response code 🙈

4. Security Considerations 🔐

Okay, this part is a little plot twist, but in a chill way. 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 🧾

Following the rules set in [RFC4412] and [RFC7134], this is an Informational RFC that creates two new namespaces, their associated priority values, and their 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 🫶

Big thank-you to Bob Fredericks, Baruh Hason, Mary Barnes, and Keith Drage for their 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