Every question of this course

Q1.1 What kind of body is CT1?

• A company forum that publishes recommendations
• A working group of 3GPP
• A regulator that licences phones

The record holds it as a working group under the parent group CT, and lists CT3, CT4, CT5 and CT6 by name beside it without saying which of those still meet. CT1 — Mobility, call control, session management (WG1_mm-cc-sm_ex-CN1)

Q1.2 How many different organisations put at least one document to CT1 in the twelve months to 2026-08-04?

• 44
• 415
• 6

415 different filing organisations appear on documents in that year. The busiest of them filed 447 documents on its own. 415 different organisations put a document to CT1 in the twelve months to 2026-08-04

Q1.3 Which group did CT1 send the most letters to in that year?

• SA2, with 19
• CT4, with 8
• RAN2, with 44

Counting only the letters addressed to a single group, RAN2 received 44 and SA2 19. 44 outgoing liaison statements to RAN2 in the twelve months to 2026-08-04

Q1.4 Whom does TS 24.501 say it applies to?

• The phone and named functions of the core network alike
• The phone only
• The network only

The scope names the UE, the AMF, the SMF and the PCF. Both ends of the conversation are bound by the same text. §1

Q2.1 How many of the specifications listed against CT1 are still active?

• 175
• 229
• 237

237 are listed against the group, 229 of them active and 8 no longer active. 175 of the active ones sit in the 24 number series. 229 active CT1 specifications

Q2.2 What are the two protocols TS 24.501 says it specifies?

• Mobility management and session management
• Billing and charging
• Radio scheduling and power control

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

Q2.3 What is the first field of every 5GS NAS message?

• The extended protocol discriminator
• The message type
• The message authentication code

Both the plain and the security protected layouts open with the extended protocol discriminator; the message type comes later. §9.1.1

Q2.4 In a message definition, what does the presence column tell you?

• Whether an information element is mandatory, conditional or optional
• How many octets long the whole message is
• Which release added the field

Each row of a message table carries a presence requirement of M, C or O, alongside the format and the length in octets. §8.1

Q3.1 How many of the 4235 CT1 documents of the last twelve months were change requests?

• 563
• 2835
• 4235

2835 were change requests and 563 were pCRs, proposed changes to a document still being drafted. 2835 CT1 documents of kind 'CR' uploaded on or after 2025-08-04

Q3.2 In a version number x.y.z, what makes the second digit go up?

• An editorial change only
• A new release of the whole 3GPP system
• Any change of substance — a technical improvement, a correction, an update

The Foreword sets the rule — the second digit covers changes of substance, the third only editorial ones. §Foreword

Q3.3 What was the most common outcome for the 617 documents put to meeting C1-161?

• agreed, 174
• revised, 259
• postponed, 70

259 came out revised and 174 agreed. The six recorded outcomes do not add up to 617, because two further outcome words carry no count. 259 documents came out of C1-161 as 'revised'

Q3.4 How many new or revised work items were agreed at C1-161?

• 219
• 5
• 9

Nine, against five at the meeting before it. 219 named work items received a CT1 document over the whole year. 9 new or revised work items were agreed at C1-161

Q4.1 A CT1 meeting has just ended. What does the record tell you about why a document was postponed?

• Nothing — it holds the outcome word and no reason
• How many companies voted against it
• The objection that was raised

The record keeps outcome words — agreed, revised, postponed, noted, merged, withdrawn — and no agenda, minutes or debate behind them. 70 documents came out of C1-161 as 'postponed'

Q4.2 Which attendance figures exist in this data?

• None at all
• Every meeting since 2005
• Only C1-161 and C1-160

172 people at C1-161 and 165 at C1-160, counted from the participant lists inside those two meeting reports. No other meeting has one, so there is no trend to describe. 172 people are listed as taking part in C1-161

Q4.3 Why can a "last twelve months" number here never be compared straight to an all-time one?

• The yearly numbers are estimates
• 7181 documents carry no upload date, so only dated rows can be counted in a year
• The record starts in 2015

The undated documents sit in the all-time counts and cannot be in any yearly one. 7181 CT1 documents carry no upload date

Q4.4 Where does a specification say what its own terms mean?

• In the meeting report that approved it
• In its own definitions and abbreviations clauses
• Nowhere — the reader is expected to know

TS 24.501 carries its own definitions and its own abbreviation list near the front, and says a definition there beats the one in the general 3GPP vocabulary document. §3.1