School of Specs CT1 — the group that writes what your…Overview

Cheat sheet

CT1 — the group that writes what your phone says

3GPP CT WG1 in one morning

Depth
Overview
Chapters
7
Reading
40 min
Questions
35
Document
TS 24.501 v20.0.0
Sources cited
115

Back to the course

The shape of it

1 Where the group sits

  1. 1 The group that writes what your phone says
  2. 2 Architecture and protocol — what stage 2 and stage 3 mean

2 What it produces

  1. 3 What the group owns, and what it actually works on
  2. 4 Inside TS 24.501, the document at the centre

3 How the work gets done

  1. 5 How a change request becomes published text
  2. 6 How a CT1 meeting runs, in real numbers
  3. 7 Following the group yourself, and what the record cannot tell you

Keep these in your head

Easy to get wrong

One from each chapter that has one. The course carries 8 in all.

  • 1.3 The group that writes what your phone says

    "Non-access stratum" does not mean "no access". It means this part of the conversation is not the access network's business: the radio carries the message and does not read it.

  • 2.3 Architecture and protocol — what stage 2 and stage 3 mean

    A newcomer reads "stage 2" and "stage 3" as steps in time, as though stage 2 were finished and handed over. They are not. Both documents are alive at once, and a change on one side usually needs a change on the other.

  • 3.2 What the group owns, and what it actually works on

    Owning 229 documents is not the same as working on 229 documents. The change counts below are heavily lopsided, and anyone who reads the list as flat has the group's shape wrong.

  • 4.5 Inside TS 24.501, the document at the centre

    The timer tables in §10 are the most quoted part of the document and the least binding. When a table and a procedure clause disagree, the procedure clause wins, and §10.1 says so itself.

  • 5.5 How a change request becomes published text

    "Agreed at CT1" and "published" are not the same event. The working group agrees a change request; the change history rows that carry CR numbers name a CT meeting and a CP- document, not the CT1 meeting the paper was agreed at. Between the two there is a step this record does not show.

  • 6.3 How a CT1 meeting runs, in real numbers

    Those six do not add up to 617, and the gap is not a mystery to be solved with arithmetic. Two further outcome words appear in the data — "approved" and "endorsed" — and the register does not carry their counts. Subtracting to get them would invent a number.

  • 7.3 Following the group yourself, and what the record cannot tell you

    The most common mistake is treating an outcome word as a judgement. "Noted" is not "rejected", "postponed" is not "refused", and neither the register nor the report says which it was. The word is what happened to the paper, not what the room thought of it.

The numbers, and where each came from

Every one was counted out of a file on this machine. Hover a row to read the question that produced it.

The document's own words

One quotation per chapter that carries one, of 5.

  • 1.3 The group that writes what your phone says

    The present document specifies the non-access stratum (NAS) procedures in the 5G system (5GS) used by the protocols for: mobility management between the user equipment (UE) and the access and mobility management function (AMF) for both 3GPP access and non-3GPP access; and session management between the user equipment (UE) and the session management function (SMF) for both 3GPP access and non-3GPP access.

  • 2.2 Architecture and protocol — what stage 2 and stage 3 mean

    The non-access stratum (NAS) described in the present document forms the highest stratum of the control plane between the UE and the AMF (reference point "N1" see 3GPP TS 23.501 [8]) for both 3GPP and non-3GPP access. … Complete NAS transactions consist of specific sequences of elementary procedures. Examples of such specific sequences can be found in 3GPP TS 23.502 [9].

  • 4.3 Inside TS 24.501, the document at the centre

    5GSM procedures can be performed only if a 5GMM context has been established between the UE and the AMF, and the secure exchange of NAS messages has been initiated by the AMF by use of the 5GMM procedures described in clause 5. Once the UE is successfully registered to a PLMN, a PDU session can be established.

  • 5.4 How a change request becomes published text

    … x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control.

The words

7 the course explains, out of 201 the document defines — all of them.

5GMM
5GS Mobility Management
5GS
5G System
5GSM
5GS Session Management
AIoT
Ambient Internet of Things
AMF
Access and Mobility Management Function
ProSe
Proximity based Services
SMF
Session Management Function

Where to look it up

The 29 clauses of TS 24.501 this course is built from.

§Foreword§1§2§3.1§3.2§4.1§4.2§5§5.1.2§5.1.3.2.1§6§6.1.1§6.1.2§7§7.1§8§8.1§9§9.2§9.11.1§10§10.1§10.2§Annex A§A.1§Annex B§Annex C§Annex D§Annex F

The 43 named sources it cites, by what they are.

Meeting document 10

C1-262074C1-262440C1-262442C1-262554C1-262596C1-262597C1-262610C1-262611C1-262612C1-262617

Specification 10

TS 24.501TS 24.301TS 24.229TS 24.554TS 04.08TS 03.68TS 23.122TS 24.379TS 24.369TR 24.860

Meeting 9

C1-156C1-157C1-158C1-159C1-160C1-161C1-162C1-163C1-164

Page on the standards body's own site 7

The CT1 file area on the 3GPP serverThe CT1 mirror area on the 3GPP serverThe 3GPP specification status reportThe CT1 list of office holdersThe 3GPP work planCT1 documents on whatthespec.netThe 3GPP meeting calendar on whatthespec.net

Official 4

CT1 Chair: CHAPONNIERE, LenaCT1 Vice Chair: AGHILI, BehrouzCT1 Vice Chair: WON, Sung HwanCT1 Secretary: BIONDIC, Nevenka

Report 2

CT1 meeting report C1-161CT1 meeting report C1-160

Working group 1

CT1 — Mobility, call control, session management (WG1_mm-cc-sm_ex-CN1)

Where to go from here