Every question of this course

Q1.1 Which document defines the stage 2 service description of IMS?

• TS 23.228
• TS 24.229
• TS 22.228

TS 23.228 says of itself that it defines the stage-2 service description for the IP Multimedia Core Network Subsystem. TS 24.229 is the protocol and TS 22.228 the requirements. the scope of 23.228

Q1.2 What does TS 24.229 define?

• The service requirements users and operators have
• A call control protocol based on SIP and the associated SDP
• The architecture of the IMS core

Its own scope says it defines a call control protocol for use in the IM CN subsystem based on the Session Initiation Protocol and the associated Session Description Protocol. the scope of 24.229

Q1.3 In the definitions clause of TS 22.228, what is an IP multimedia service?

• A conference with two or more participants
• Any session carried over an IP bearer
• The user experience provided by one or more IP multimedia applications

The document keeps three words apart. A session is senders, receivers and streams; an application handles the media types; a service is the experience one or more applications provide. "IP multimedia service" as 22.228 defines it

Q1.4 What is a data channel application, as TS 23.228 defines it?

• An HTML page with JavaScript, downloaded from the network to the phone
• A separate app the subscriber installs on the phone
• A media codec negotiated for the data channel

The definition is literally a web page. It is downloaded to the device over the bootstrap data channel, and may also carry images and style sheets. "Data channel application" as 23.228 defines it

Q1.5 What can this course tell you about how an IMS session is actually set up?

• Only the parts CT1 has agreed
• Nothing — the register behind it holds no procedure, message or parameter
• The full signalling flow, from the register's quoted clauses

The register holds titles, scopes, definitions, objectives and counts. Anything about how the system works has to be read in the specifications themselves. the scope of 23.228

Q2.1 What decides whether a work plan row belongs to this course?

• The row names one of the four IMS specifications
• The acronym of the row carries IMS with no capital letter in front of it
• The title of the row contains "IMS"

The rule is applied to the acronym alone. Titles are never tested, because several real IMS work items have the letters nowhere in their names. 345 rows of the 3GPP work plan are IMS work

Q2.2 How many rows and how many acronyms does that rule take in?

• 177 rows under 345 acronyms
• 345 rows under 345 acronyms
• 345 rows under 177 acronyms

One acronym often has several rows, because a row is one group's share of one work item. So the two counts answer different questions and neither is the number of work items a person would name. 177 different work item acronyms carry IMS

Q2.3 Why does the rule allow a lower-case letter in front of the three letters?

• Because 3GPP writes "enhanced" as a small letter in front of a name, as in eIMS_RP and enIMS
• Because acronyms are stored in lower case
• To catch spelling mistakes in the work plan

A boundary that also forbade a lower-case letter would leave 163 acronyms and throw out eIMS5G_SBA, eIMS_RP, enIMS and FS_enIMS_ARC, which are real IMS work. 163 of those acronyms survive a boundary that also forbids a lower-case letter

Q2.4 What is true of every document count in this course?

• It counts only change requests
• It is a floor and never a total
• It counts every document 3GPP ever wrote about IMS

A document is counted only when its work item column names one of the 177 acronyms, and no IMS document earlier than 2015-01-23 carries an acronym in this store at all. the earliest IMS document on record went up on 2015-01-23

Q2.5 What may a chapter say about a work item with no quotable description?

• What it probably intended, from its title
• What its acronym suggests
• Nothing about what it set out to do

For 20 of the 177 acronyms the folder holds no description that proves it belongs to that row. IMS2 is one of them, so nothing may be written about what IMS phase 2 promised. 157 of the 177 IMS acronyms have a work item description on this machine

Q3.1 What is the title of the founding IMS row in the work plan?

• Provisioning of IP-based multimedia services
• Support of IP multimedia services
• IP Multimedia Subsystem, Stage 2

The row's acronym is bare IMS and its title is "Provisioning of IP-based multimedia services". The third option is the title of the description document behind it, which is a different thing. IMS

Q3.2 In its own words, what was the objective of that first work item?

• To build a packet-switched replacement for the circuit core
• To define general service requirements and service features for Release 2000, an evolved Release 99 plus IP Multimedia services
• To define the SIP profile a phone would use

The objective is stage 1 work — concepts, requirements and features — and it adds that IP multimedia services shall support multiple media components per call. what IMS set out to do

Q3.3 What may this course say about when meeting SP-8 was held?

• That it was held in 2000, from the paper's number
• That it was held on the work item's planned start day
• Nothing — the meeting store has no row for it

SP-8 is one of four meetings named here for which the store holds no days and no place. The meeting may be named and never dated. SP-000216

Q3.4 Why is the Rel-5 document count not a measure of how much work was done?

• Because no IMS document earlier than 2015-01-23 carries a work item acronym in this store
• Because change requests were not counted until Rel-8
• Because Rel-5 rows were never given acronyms

The founding row has one document against its name. That is a fact about when the store began labelling documents, not about the work. the earliest IMS document on record went up on 2015-01-23

Q3.5 What does the "100%" on a work plan row tell you?

• That the work item was formally closed
• Only that somebody typed 100 into a field the plan keeps by hand
• That every specification it targeted was published

339 of the 345 IMS rows stand at 100%. It is a completion percentage maintained by hand, and no field anywhere says whether a work item is running, stopped or finished. 339 of the 345 IMS work plan rows stand at 100%

Q4.1 What did IMS-CCR-IWCS set out to do?

• Address interworking between the IM CN subsystem and circuit switched networks, in order to support basic voice calls
• Replace the circuit switched network entirely
• Define how two IMS networks connect to each other

Its objective is one sentence, and "basic voice calls" is the whole ambition of it. Its justification names the PSTN, ISDN and the GSM and UMTS circuit networks as what had to be reached. what IMS-CCR-IWCS set out to do

Q4.2 How many work plan rows did the paper SP-020065 open?

• Two, for messaging and group management
• Five, under the acronyms IMSGM, IMSM, IMSM-CR, IMSM-TR and IMSM-TS
• One, for IMS messaging

One plenary paper can define several rows at once. The store lists all five work items against that document number. SP-020065

Q4.3 What may this course say about what IMS phase 2 promised?

• That it delivered messaging and group management
• That it was the second phase of the founding work item
• Nothing at all about its objectives

IMS2 is one of the 20 acronyms with no quotable work item description, so nothing may be written about what it said it would do. Its row, its release and its groups are all the register holds. IMS2

Q4.4 What is IMSProtoc, opened in Rel-7?

• IMS Stage 3 IETF Protocol Alignment — keeping 3GPP's use of SIP in step with the IETF
• The first version of the SIP profile
• A conformance test suite for IMS protocols

It is the first of a numbered chain that has been reopened in release after release, which is why its phase 2 alone carries 248 documents. IMSProtoc

Q5.1 Which release carries the most IMS work plan rows?

• Rel-8, with 64
• Rel-9, with 45
• Rel-12, with 60

Rel-8 at 64 leads, Rel-12 at 60 is second and Rel-9 at 45 is third. Any ranking here is over the 345 rows this register takes in, and says nothing about 3GPP work outside it. 64 IMS work plan rows are marked Rel-8

Q5.2 Why was IMS_EMER_GPRS_EPS opened?

• To let emergency calls reach IMS from Wi-Fi
• To prepare for meeting regional regulatory requirements for packet-switched emergency calls
• Because circuit-switched emergency calls had been withdrawn

Its justification names regional regulatory requirements and staying competitive with other wireless packet technologies, and its objective is the requirements for emergency calls over GERAN, UTRAN and E-UTRAN. why IMS_EMER_GPRS_EPS was proposed

Q5.3 What did eIMS_RP exist to finish?

• The transfer of the TISPAN documents
• The interworking with circuit-switched networks
• The P-CSCF part of the IMS restoration procedures, left unfinished in Rel-8

Rel-8 specified restoration for S-CSCF service interruption in TS 23.380. The P-CSCF procedures studied in TR 23.820 were not finished in that timeframe, and this work item was opened to complete them. why eIMS_RP was proposed

Q5.4 How does the register describe IMS Service Continuity, in TS 23.237's own scope?

• As the architectural requirements and procedures for delivery of IMS Service Continuity
• As the ability to hand a call between two operators
• As a way to restore a session after a network failure

The scope is one sentence and it is deliberately narrow. What continuity is *for* comes from the work item that opened it, not from the specification's own scope. the scope of 23.237

Q5.5 What is the "common IMS" in the TISPAN maintenance rows?

• The part of IMS every release must implement
• The name the work plan gives to specifications brought into 3GPP from TISPAN and maintained there
• A shared deployment run by several operators

The rows are titled "Maintenance of TISPAN release 1 common IMS" and "Documentation of TISPAN NGN R1 and R2 in 3GPP SA WG2", and the specifications they target carry TISPAN in their own titles. IMS_Comm_Mtce8

Q6.1 What did IMS_WebRTC say it would specify?

• A new browser
• A replacement for SIP
• Service requirements for WebRTC clients to reach IMS

Its objective is service requirements for the ability for WebRTC clients to access IMS, reusing IMS client security credentials and public identities where that made sense. what IMS_WebRTC set out to do

Q6.2 The work plan holds 60 IMS rows for Rel-12 and 15 for Rel-13. What does that pair of numbers tell you about how much work was done?

• Nothing on its own — a row is one group's share of one work item, and the document counts run the other way
• Rel-13 was cancelled
• Rel-12 was four times the work of Rel-13

Rel-12 has 60 rows and 433 documents; Rel-13 has 15 rows and 830. Rows count bookkeeping entries, documents count paper, and neither measures effort. 15 IMS work plan rows are marked Rel-13

Q6.3 Which specification is the stage 3 protocol for WebRTC access to IMS?

• TS 24.103
• TS 24.371
• TS 26.223

TS 24.371 is "WebRTC access to the IM CN subsystem; Stage 3; Protocol specification", owned by CT1, with 160 IMS documents against it. TS 24.371

Q6.4 Six Rel-12 acronyms for registration control carry no documents at all. What else do they have in common?

• They were all rejected by a vote
• They belong to SA4
• Every one of their names begins with the word Deleted

All six IMS_RegCon rows are titled "Deleted - …". That prefix is typed into the title by hand; the work plan carries no status field, and the register holds no vote of any kind. 22 IMS work item acronyms carry the word Deleted at the front of their own name

Q6.5 What is IMSProtoc, in one line?

• The protocol alignment work, opened once and continued as a numbered phase in every release since
• A single work item that ran in Rel-7 and closed
• The conformance test suite for IMS

Phases 4 to 8 fall inside these five releases alone, with 19, 248, 209, 364 and 169 documents against them. 364 documents carry the work item IMSProtoc7

Q7.1 Why was IMS work needed at all when the 5G core was specified?

• Because the radio groups asked for it
• Because IMS was being replaced by a 5G call control protocol
• Because voice, emergency call included, is a basic service, and SA2 had agreed IMS would still provide it with the 5G core underneath

The Rel-15 work item's justification says exactly that, and calls the 5G core a new type of IP connectivity for reaching IMS. why 5GS_Ph1-IMSo5G was proposed

Q7.2 What did the Rel-16 study give as the reason it was needed?

• The first 5G core work had deliberately kept the IMS scope small, to avoid a re-specification that might have delayed it
• The Rel-15 work had failed
• Regulators required it

Its justification says the scope was intentionally limited to avoid major IMS re-specification that might delay initial 5GC specification. why FS_eIMS5G was proposed

Q7.3 Which acronym has more documents against it than any other in this register?

• IMSProtoc7, with 364
• eIMS5G_SBA, with 543
• 5GS_Ph1-IMSo5G, with 476

543 documents name eIMS5G_SBA, ahead of 5GS_Ph1-IMSo5G's 476. It is a count over this register and says nothing about 3GPP as a whole. 543 documents carry the work item eIMS5G_SBA

Q7.4 Why was a second phase of the enhanced-IMS-to-5GC study opened in Rel-17?

• The 5G core changed
• The first study was withdrawn
• Key issues 1, 2, 3 and 8 of the first study were not finalised and no solutions were agreed for them

The second study's own justification names those four key issues as unfinished, while saying the service-based conclusions had been reached. why FS_eIMS5G2 was proposed

Q7.5 What is TR 23.794 in this course?

• A document that may be named and counted but not quoted here
• A specification this course teaches clause by clause
• A CT1 protocol document

It is the Rel-16 study report with 190 IMS documents against it, and this machine holds no parsed text of it, so no clause of it may be cited. TR 23.794

Q8.1 The three largest document counts in this record belong to which family of groups?

• The CT working groups, which is what a core-network subject looks like
• The SA groups, because they write the architecture
• The RAN groups, because IMS is a radio subject

CT1 with 2169, CT4 with 746 and CT3 with 719 lead the record. IMS is a core-network subject and the shape of the counts says so. CT1

Q8.2 How many separate meetings have had an IMS document on the table?

• 4939
• 309
• 374

309 meetings. 374 is the number of different names that appear as a writer, and 4939 is the document count. 309 meetings have had IMS documents on the table

Q8.3 Ericsson appears with 602 documents and "Ericsson / Nevenka" with 130. What may you do with those two numbers?

• Ignore the smaller one
• Add them, since it is one company
• Neither add them nor treat either as that company's total — the column is free text and nothing here resolves a name to a parent company

The count is grouped by the name each document spelled. Two spellings count twice, and this register never joins them. Ericsson / Nevenka filed 130 IMS documents

Q8.4 RAN2 has exactly one IMS document in this record. What can you say about it?

• That it is tagged with the work item IMS-CODEC at meeting R2-92, and nothing more
• That it is a liaison from another group
• That it is a change request to a radio specification

The register records the acronym and the meeting. It does not record what kind of document it is, so calling it a change request, a liaison or RAN2's own work would be an invention. RAN2

Q8.5 What do the plenary rows — CT with 221, SA with 34, RAN with 25 — mostly carry?

• Nothing, they are placeholders
• {'The decisions': 'work items opened, revised and reported on'}
• The technical text

Working groups write the text and plenaries approve the work. The plenary counts are small next to CT1's 2169 and that is the normal shape. CT

Q9.1 Which meeting handled more IMS documents than any other in this record?

• CT1#112, at West Palm Beach in August 2018, with 206
• CT1#90, at Sorrento in February 2015, with 159
• The CT plenary CP-112, at Singapore in June 2026

206 IMS documents at C1-112, ahead of C1-90's 159. It is a count over the IMS documents in this register and nothing wider. C1-112 handled 206 IMS documents, more than any other single meeting

Q9.2 How many IMS documents in this record name TS 24.229 as the document they change?

• 746
• 1680
• 206

1680, of which 1675 are a change request, a change-request pack or a draft change request. It is the largest target in the register by a long way. 1680 IMS documents name 24.229 as the document they change

Q9.3 Both IMS restoration studies belong to which group?

• CT3
• CT1
• CT4

TR 29.866, the disaster prevention and restoration study, and TR 29.867, the resiliency study, are both owned by CT4. TR 29.866

Q9.4 A meeting entry in this register carries days and a place. What does it not always carry?

• A registration count — 31 of the meetings here have none
• The number of IMS documents
• The meeting code

The attendance store reaches back only a little way. Four older meetings named elsewhere in this register have no row at all, so they can be named and not dated. C1-112

Q9.5 What does CT3 own that the other CT groups do not?

• The restoration procedures
• The interworking documents — TS 29.163 for circuit-switched networks and TS 29.165 between two IMS networks
• The SIP profile

CT3's subject is interworking with other networks, and those two documents carry 228 and 190 IMS documents against them. TS 29.163

Q10.1 Which group owns TS 23.228, the stage 2 description of IMS?

• SA1
• SA2
• CT1

SA2 is the architecture group. It owns TS 23.228 and carries 429 IMS documents over 30 meetings in this record. TS 23.228

Q10.2 What does SA4 do in this subject?

• The security assurance
• The charging
• The media — telepresence media handling, split rendering over IMS, and the AI/ML media work item

186 documents, and the acronyms named against it are the two telepresence media items, split rendering and the AI/ML media item. SA4

Q10.3 RAN5 has 147 IMS documents. What is it doing with them?

• Conformance testing — proving a device behaves the way the specification says
• Approving work items
• Writing the radio protocol

RAN5 is the mobile terminal conformance testing group. Its four acronyms here are all test items, two of them for the IMS data channel. RAN5

Q10.4 How many IMS documents in this record are of the type "LS out", a letter sent to another group?

• 4
• 45
• 15

45 documents carry that type. The register gives an entry of its own to fifteen of them, the ones whose outcome word is approved or agreed. 45 IMS documents are of type LS out

Q10.5 The plenaries carry CT 221, SA 34 and RAN 25 IMS documents. Why so few?

• Because plenaries meet rarely
• The record is incomplete for plenaries
• Because a plenary opens, revises, approves and reports on work, while the text itself is written in the working groups

The CT plenary alone shows 44 meetings for its 221 documents — a few papers at a great many meetings, which is what deciding looks like. CT

Q11.1 How does a document get onto this course's list of 241 specifications?

• It is owned by one of the fourteen groups that do IMS work
• A work item names it as one it changes, or at least three IMS documents name it in their change-request column
• Somebody mentions it once in a meeting

Those are the two tests, and a document passes if either is true. One catches what was promised, the other catches what actually landed. 241 specifications this work touches

Q11.2 Which document carries by far the most IMS change traffic?

• TS 29.562, the 5G core's subscriber-data services
• TS 23.228, the stage 2 description
• TS 24.229, the protocol specification, named by 1680 IMS documents

1680 of the 4939 IMS documents in this record name TS 24.229 as the document they change. TS 23.228 is named by 92. 1680 IMS documents name 24.229 as the document they change

Q11.3 A stored version carries a date. What is that date?

• The day the version file went up on the 3GPP server
• The day the document was published
• The day the plenary approved it

The register says so in the entry itself. Publication day and approval day are not held anywhere on this machine. TS 23.228

Q11.4 72 of the 241 specifications have no parsed text on this machine. What may a course do with them?

• Cite their clauses
• Name them and count what was written about them, and quote nothing
• Quote their scope

No parsed text means no words to check a quotation against. Naming and counting are safe; quoting is not. 241 specifications this work touches

Q11.5 TR 23.794 and TS 23.228 are different kinds of document. What is the difference?

• The TR is older
• The TR is a draft of the TS
• A report records a study and binds nobody; a specification is a rule other people have to follow

TR 23.794 is the Rel-16 study on putting IMS on the 5G core. TS 23.228 is the stage 2 rule. The study fed the rule and never replaced it. TR 23.794

Q12.1 What kind of document makes up most of this subject's paperwork?

• Change requests — 3509 of the 4939 documents on record
• Study reports
• Liaisons between groups

3509 are change requests, plus 175 change-request packs and 38 draft change requests. Everything else is a small share. 3509 IMS documents are of type CR

Q12.2 A change request carries the outcome word "agreed". What does that tell you?

• That the specification has been published
• That this document was agreed at the meeting it was brought to, and nothing about the work item it belongs to
• That the work item is finished

The outcome word is about that one document. 1736 IMS documents carry agreed and no store here says what any of them meant for the work. 1736 IMS documents carry the outcome word agreed

Q12.3 How often has the IETF protocol alignment work been reopened?

• Only when the IETF publishes something new
• Once, in Release 7
• Every release from Rel-7 to Rel-20, under a run of numbered acronyms

IMSProtoc, then IMSProtoc2 to IMSProtoc9, then IMSProtoc16 to IMSProtoc20-CT. Fourteen entries, one job. IMSProtoc

Q12.4 The justification of IMSProtoc2 in Rel-8 and of IMSProtoc20-CT in Rel-20 are

• The same two sentences, one word apart — "provides" became "provided"
• Completely different
• The Rel-20 one is much longer

Both open by saying that Release 5 defined IMS and that its feature set is a basis for IP Multimedia support. Nothing else changed. why IMSProtoc20-CT was proposed

Q12.5 339 of the 345 IMS work plan rows stand at 100%. What does that number mean?

• That every change request was approved
• A percentage the work plan keeps by hand, which is not a status field
• That the work is finished and closed

The register holds no status field for a work item at all. The percentage is bookkeeping somebody types in. 339 of the 345 IMS work plan rows stand at 100%

Q13.1 Why was the Release 19 resiliency study opened?

• To add a new service
• Because IMS-related communication accidents had happened on different operators' networks and affected voice, video and SMS for millions of people
• Because the IETF changed SIP

The justification says exactly that, and names finance, aviation, logistics, automobile and electric power as the industries hit. why FS_IMS_RES was proposed

Q13.2 What does the Release 20 architecture study give as its reason for existing?

• Falling call quality
• A shortage of IP addresses
• Generative AI, large language models, AI agents, AI glasses and embodied robots, plus SA1's own 6G requirements study

Those are the words of the justification. The study itself is about multi-vendor interoperable interfaces for those services. why FS_enIMS_ARC was proposed

Q13.3 The Release 20 architecture study names one report number and 47 IMS documents name another. What does this course do?

• Writes both numbers out and says the data does not settle it
• Picks the one with more documents
• Leaves both out

TR 23.801-03 is what the work item's own table names; TR 23.801-04 is what 47 IMS documents target and what the catalogue titles "Study on IMS Architecture Enhancement". TR 23.801-04

Q13.4 One Release 20 study carries "Deleted" at the front of its own name. What else does the record hold about it?

• Nothing at all
• An approved study paper, SP-251237, and 16 meeting documents
• A closing date

Both facts are in the record and both have to be written. "Deleted" is typed into the title by hand and is not a status field. FS_IMSRE_SEC

Q13.5 How many IMS work plan rows are marked Release 20?

• 189
• 45
• 7

7 rows for Rel-20 and 10 for Rel-19. A row is one group's share of one work item, so a handful of acronyms fills them. 7 IMS work plan rows are marked Rel-20

Q14.1 Why is searching for the word IMS in a work item's title the wrong way to find this work?

• The search is too slow
• Real IMS work items have titles that never mention IMS — the founding one is called "Provisioning of IP-based multimedia services"
• The titles are not stored

IMS, IMS-CODEC, IMS_SSFDD and IMS_Corp2 all carry IMS in the acronym and none of them carries it in the title. Search the acronym. IMS

Q14.2 113 of the 151 papers that opened a work item carry 2017-10-05 as their upload stamp. What is that day?

• The day the plenary approved them
• The day they were written
• The day the store took the files in

SP-000216 was written for a meeting years before 2017 and carries that stamp. Date an old paper by its meeting, or not at all. SP-000216

Q14.3 What does the record hold about why a group decided something?

• Nothing — it holds the outcome word a document was given and no reason
• The minutes of the discussion
• A summary written by the chairman

No store on this machine records a reason, a vote or an objection. The nearest thing to a reason is a work item description's own justification. 379 IMS documents carry the outcome word approved

Q14.4 IMS2, VoIMS and IMS-MMTel have no quotable work item description. What may this course say about what they set out to do?

• What the most similar work item said
• Nothing at all
• What their titles imply

IMS2, VoIMS and IMS-MMTel are among the 20 acronyms with no description that can be proved to belong to them. Nothing may be written about their objectives. IMS2

Q14.5 Every count in this course carries a method line. Why?

• Because 3GPP requires it
• To fill space
• Because a number whose origin nobody can restate is a number nobody should trust

The method says the exact question that produced the number and the day it was asked, so the count can be run again and checked. 241 specifications this work touches