Every question of this course

Q1.1 Which two ends of the network does the document CT1 is best known for describe the conversation between?

• The phone and the base station
• The phone and the core network functions that handle mobility and sessions
• Two operators' networks at a border

The scope names mobility management between the UE and the AMF, and session management between the UE and the SMF. §1

Q1.2 What is CT1's code in the specification catalogue, and what goes in front of every document number it handles?

• CT1 and CT1-
• C1 and C1-
• CN1 and CN1-

Three stores spell the group three ways — C1 in the catalogue, C1- in front of every document number, and "3GPP CT 1" in the meeting calendar. CT1 — Mobility, call control, session management (WG1_mm-cc-sm_ex-CN1)

Q1.3 How many people hold office in CT1 with no end date on record?

• Nine
• Two
• Four

A chair, two vice chairs and a secretary are the four office holders with no end date in the file. 4 CT1 office holders have no end date on record

Q1.4 Where does the non-access stratum sit, according to the document's own words?

• Below the radio layers, closest to the antenna
• The highest stratum of the control plane between the UE and the AMF
• Alongside the user data, in the same messages

Clause 4.1 places the NAS at the top of the control plane between the UE and the AMF, for both 3GPP and non-3GPP access. §4.1

Q2.1 What does the phrase "Stage 3" at the end of a specification title tell you?

• The document is still a draft, two stages from finished
• The document describes the protocol itself, not the architecture around it
• The document is the third edition

TS 24.501's own title ends "Stage 3", and its scope is the NAS procedures themselves — the messages, not the system picture. §1

Q2.2 According to clause 4.1, where would you look for a complete sequence of the elementary procedures TS 24.501 defines?

• Nowhere — a complete sequence is left to implementation
• In clause 5 of the same document
• In TS 23.502, which the clause names for exactly this

Clause 4.1 says complete NAS transactions consist of sequences of elementary procedures and points at TS 23.502 for examples of them. §4.1

Q2.3 Timer T3510 is started when the phone sends a REGISTRATION REQUEST. What is its value on the UE side?

• 15 seconds
• 54 minutes
• 10 seconds

The UE-side timer table gives T3510 as 15 s, with longer values in some modes and over satellite access. §10.2

Q2.4 Which group does CT1 exchange the most incoming letters with?

• SA2
• CT4
• RAN2

39 incoming liaison statements came from SA2 in the year, more than from any other single group; RAN2 leads the outgoing direction with 44. 39 incoming liaison statements from SA2 in the twelve months to 2026-08-04

Q2.5 How many CT1 documents changed 24.501 over the whole record?

• 15623
• 2447
• 5422

24.501 is by a wide margin the most-changed document in the group's history, at 15623 change documents. 15623 CT1 documents change 24.501 (Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3), over the whole record

Q3.1 How many CT1 specifications are active?

• 229
• 237
• 199

237 are listed against the group; 229 of those are active and 8 are not. 229 active CT1 specifications

Q3.2 Of the active documents, how many are technical reports rather than technical specifications?

• 8
• 30
• 175

199 are technical specifications and 30 are technical reports. 30 active CT1 technical reports (TR)

Q3.3 Which document has the most change documents against it in the twelve months to August 2026?

• 24.369
• 24.501
• 24.301

In that year 24.301 leads with 499, just ahead of 24.501 with 498 — an order that is the reverse of the all-time list. 499 CT1 documents change 24.301 (Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3), in the twelve months to 2026-08-04

Q3.4 How many named work items received a CT1 document in the last twelve months?

• 219
• 415
• 6

219 named work items received at least one document in the year; the six busiest are named in this chapter. 219 named work items received CT1 documents in the twelve months to 2026-08-04

Q3.5 What does the register say the work-item name MINT_Ph2 stands for?

• Nothing — it holds the names exactly as the documents spell them and no expansion
• Mobile Internet Phase 2
• It gives the full title in every entry

Work-item names are stored as spelled. Anything they stand for would have to come from elsewhere, so this course does not guess. 172 CT1 documents for the work item MINT_Ph2 in the twelve months to 2026-08-04

Q4.1 Which two protocols does TS 24.501 carry side by side?

• Session management and charging
• Mobility management and session management
• Radio resource control and mobility management

Clause 5 holds the mobility management procedures and clause 6 the session management procedures, and clause 4.2 governs how the two overlap. §5.1.2

Q4.2 How many types of mobility management procedure does clause 5.1.2 distinguish?

• Three — common, specific, and connection management
• Six, one per state
• Two — network-initiated and UE-initiated

The clause splits them by how they can be started — common procedures, specific procedures, and connection management procedures. §5.1.2

Q4.3 A session management procedure can only run once what exists?

• An established 5GMM context, with secure exchange of NAS messages already started
• A PDU session in the PDU SESSION ACTIVE state
• An approved change request

Clause 6.1.1 makes 5GSM procedures conditional on a 5GMM context and on the AMF having started secure message exchange. §6.1.1

Q4.4 The timer tables in clause 10 disagree with clause 5 about a detail. Which wins?

• Clause 10, because the tables are the normative list
• Clause 5, because clauses 4 to 6 are the definitive descriptions
• Whichever was changed most recently

Clause 10.1 calls the tables a brief summary and names clauses 4 to 6 as the definitive descriptions. §10.1

Q4.5 Where in TS 24.501 would you look up what 5GMM cause

• Clause 9, with the other coded values
• Annex A, which lists the mobility management cause values
• Clause 3.1, with the definitions

Annex A holds the 5GMM cause values; A.1 covers those related to UE identification, where §A.1

Q4.6 What is Annex F of the document?

• The list of references to other specifications
• A worked example of a registration
• The change history — every approved change, with its number and the version it landed in

Annex F is the change history table; the reference list is clause 2. §Annex F

Q5.1 What is the difference between a CR and a pCR?

• A CR changes a published specification; a pCR changes one still being drafted
• A pCR is a rejected CR
• A CR is bigger; a pCR is a one-line correction

The two document kinds are counted separately because they act on documents at different stages of life. 563 CT1 documents of kind 'pCR' uploaded on or after 2025-08-04

Q5.2 How many CT1 documents in the last twelve months were change requests?

• 563
• 2835
• 4235

Of 4235 documents in the year, 2835 were change requests and 563 were pCRs. 2835 CT1 documents of kind 'CR' uploaded on or after 2025-08-04

Q5.3 In the version number x.y.z of a 3GPP specification, what does a change in the third digit mean?

• A new Release
• A change of substance
• Editorial changes only have been incorporated

The Foreword defines the third digit as incremented for editorial-only changes and the second for changes of substance. §Foreword

Q5.4 What kind of meeting is named on the change-history rows of TS 24.501 that carry a CR number?

• A CT meeting, with a CP- document number beside it
• No meeting is recorded
• The CT1 working group meeting that agreed it

Once the document is under change control, the change history records the CT plenary meeting and its document number, not the working group's. §Annex F

Q5.5 The change request C1-262074 was agreed at C1-161. Which document does it change?

• 24.301
• 24.501
• 24.554

The register entry names 24.501, version 19.6.2, CR number 7174, category F, under the work item 5GProtoc20-CT. C1-262074

Q6.1 How many documents were put to the meeting C1-161?

• 172
• 617
• 4235

617 documents were filed against that meeting; 172 is the number of people listed as taking part. 617 documents were put to C1-161

Q6.2 Which outcome did most documents at C1-161 receive?

• revised
• postponed
• agreed

259 came out revised, ahead of 174 agreed and 70 postponed. 259 documents came out of C1-161 as 'revised'

Q6.3 The six outcome counts for C1-161 do not add up to 617. Why can you not work out the difference?

• Some documents were never opened
• The total of 617 includes documents from the next meeting
• Two more outcome words exist and the register does not carry their counts

Two further words, "approved" and "endorsed", appear in the data without counts, so subtracting would produce a number nobody can check. 174 documents were agreed at C1-161

Q6.4 How many CT1 meetings are listed, held and planned together?

• 184
• 133
• 172

184 are listed; 172 had started by 2026-08-04, and 133 have documents on record. 184 CT1 meetings are listed, held and planned

Q6.5 What is the state of the meeting report for C1-161?

• Approved
• A draft, whose numbers can still change
• Not written

The C1-161 report is a draft; the report of the meeting before it, C1-160, is approved. CT1 meeting report C1-161

Q7.1 Somebody says "CT1 agreed that at C1-162". What is wrong with the sentence?

• C1-162 is not a CT1 meeting
• Nothing — documents are already filed under C1-162
• C1-162 has not started, so nothing has been agreed there

69 documents are filed under C1-162, but it is a planned meeting; nothing has been agreed, revised or postponed there. C1-162

Q7.2 Why can a "documents in the last twelve months" number not be compared with an all-time number?

• 7181 documents carry no upload date, so yearly counts are counts of dated rows only
• The yearly numbers include planned meetings
• The all-time number counts meetings, not documents

The all-time counts include undated rows; the yearly ones cannot, so the two are counted on different populations. 7181 CT1 documents carry no upload date

Q7.3 Can this record tell you why CT1 postponed a particular document?

• No — it holds the outcome word and nothing about why
• Only for documents that were later agreed
• Yes, the meeting report gives the reason for each postponement

There is no agenda, no minutes and no record of debate; the outcome word is all there is. 70 documents came out of C1-161 as 'postponed'

Q7.4 How many of the 229 active CT1 specifications have parsed text available here?

• 157
• 199
• All 229

Only 157 have parsed text on this machine, so a clause can be quoted from those and only those. 157 of 229 active CT1 specifications have parsed text on this machine

Q7.5 Which claim about CT1 can this register never support?

• That C1-161 was held in China
• That CT1 is the busiest of the CT working groups
• That 24.501 has more change documents against it than 24.301

The register was built for CT1 alone and holds no document, specification or meeting count for any other group. CT1 — Mobility, call control, session management (WG1_mm-cc-sm_ex-CN1)