ETSI TS 123 087 V17.0.0 (2022-04)

Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); User-to-User Signalling (UUS) supplementary service; Stage 2 (3GPP TS 23.087 version 17.0.0 Release 17)

ETSI TS 123 087 V17.0.0 (2022-04)

Name:ETSI TS 123 087 V17.0.0 (2022-04)   Standard name:Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); User-to-User Signalling (UUS) supplementary service; Stage 2 (3GPP TS 23.087 version 17.0.0 Release 17)
Standard number:ETSI TS 123 087 V17.0.0 (2022-04)   language:English language
Release Date:   technical committee:3GPP CT 4 - MAP/CAMEL/GTP/BCH/SS/TrFO/IMS/GUP/WLAN (formely CN4)
Drafting committee:   ICS number:
ETSI TS 123 087 V17.0.0 (2022-04)






TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
Universal Mobile Telecommunications System (UMTS);
User-to-User Signalling (UUS) supplementary service;
Stage 2
(3GPP TS 23.087 version 17.0.0 Release 17)



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3GPP TS 23.087 version 17.0.0 Release 17 1 ETSI TS 123 087 V17.0.0 (2022-04)

Reference
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ETSI

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3GPP TS 23.087 version 17.0.0 Release 17 2 ETSI TS 123 087 V17.0.0 (2022-04)
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ETSI

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3GPP TS 23.087 version 17.0.0 Release 17 3 ETSI TS 123 087 V17.0.0 (2022-04)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 7
4 General . 7
4.1 Activation of UUS components . 7
4.1.1 Implicit request . 7
4.1.2 Explicit request . 8
4.1.3 UUS required option . 8
5 Handling of User-to-user signalling . 8
5.1 Timers . 8
5.2 Information flows of UUS services . 9
5.2.1 Service 1 (UUS1) . 9
5.2.1.1 Flow control . 9
5.2.1.2 Information flows . 10
5.2.1.2.1 Implicit activation . 11
5.2.1.2.2 Explicit activation . 12
5.2.2 Service 2 (UUS2) . 13
5.2.2.1 Flow control . 13
5.2.2.2 Information flows . 13
5.2.3 Service 3 (UUS3) . 15
5.2.3.1 Flow control . 15
5.2.3.2 Information flows . 16
5.3 Messages and their contents . 19
5.3.1 Information elements used in the messages . 19
5.3.2 Messages between MS and MSC . 19
5.3.3 Messages between MSC and VLR (B interface) . 20
5.3.4 Messages between MSC – MSC (E interface) . 20
6 Interaction with other supplementary services . 21
6.1 Call forwarding unconditional (CFU) . 21
6.2 Call forwarding on mobile subscriber busy (CFB) . 21
6.3 Call forwarding on no reply (CFNRy) . 21
6.4 Call forwarding on mobile subscriber not reachable (CFNRc) . 21
6.5 Call waiting (CW) . 21
6.6 Call hold (HOLD) . 22
6.7 Completion of calls to busy subscribers (CCBS) . 22
6.8 Explicit call transfer (ECT) . 22
6.9 Multi party service (MPTY) . 22
6.10 Advice of charge (AoC) . 22
6.11 Barring of outgoing calls (BAOC) . 22
6.12 Barring of outgoing international calls (BOIC) . 22
6.13 Barring of outgoing international calls except those directed to the home PLMN country (BOIC-exHC) . 22
6.14 Barring of incoming calls (BAIC) . 22
6.15 Barring of incoming calls when roaming outside the home PLMN country (BIC-Roam) . 22
6.16 Call deflection (CD) . 23
7 Interaction with other network features . 23
7.1 Customised Applications for Mobile network Enhanced Logic (CAMEL) . 23
ETSI

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3GPP TS 23.087 version 17.0.0 Release 17 4 ETSI TS 123 087 V17.0.0 (2022-04)
7.2 Support for Optimal Routeing(SOR) . 23
8 Interworking with other networks . 23
8.1 Interworking with GSM PLMN/ISDN network supporting only a maximum User-user information
element length of 35 octets . 23
8.2 Interworking with non-ISDN network . 23
9 Network entity functions . 24
9.1 Originating network processes . 24
9.1.1 Procedures in MSC . 24
9.1.2 Procedures in VLR. 28
9.2 Terminating network processes . 29
9.2.1 Procedures in GMSC . 29
9.2.2 Procedures in MSC . 30
9.3 Procedures common in serving and remote networks . 36
9.4 Processes used during Active Call . 46
9.4.1 Process and procedures in serving MSC . 46
9.4.2 Process and procedures in serving VLR . 52
9.4.3 Process and procedures in remote MSC . 53
10 Information stored in the HLR and in the VLR . 56
10.1 Information stored in the HLR . 56
10.2 Transfer of information from HLR to VLR . 57
10.3 Information stored in the VLR . 57
11 State transition model . 57
12 Handover . 57
Annex A (informative): Change history . 58
History . 59

ETSI

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3GPP TS 23.087 version 17.0.0 Release 17 5 ETSI TS 123 087 V17.0.0 (2022-04)
Foreword
rd
This Technical Specification (TS) has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
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.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
ETSI

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3GPP TS 23.087 version 17.0.0 Release 17 6 ETSI TS 123 087 V17.0.0 (2022-04)
1 Scope
The present document gives the stage 2 description of the User-to-User signalling supplementary services.
The User-to-user supplementary service is divided into 3 different services:
- Service 1 (UUS1)
- Service 2 (UUS2)
- Service 3 (UUS3)
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TS 21.905: "3G Vocabulary".
[2] 3GPP TS 22.087: "User-to-user signalling (UUS); Stage 1".
[3] 3GPP TS 23.018: "Basic Call Handling – Technical Realization".
[4] 3GPP TS 23.078: "CAMEL Stage 2".
[5] 3GPP TS 23.079: "Support for Optimal Routeing (SOR) – Technical Realization".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply.
Burst parameter: parameter indicating the absolute maximum number of UUS 3 service related user information
messages that can be sent at intervals indicated by the value of timer T2-UUS3
Remote network: network of the remote subscriber
Remote subscriber: for service 1 and 2 the remote subscriber is the called party of a call to which the served subscriber
activates the UUS supplementary service. For service 3 the remote subscriber can be either the called or the calling
party of an established call to whom the use of the UUS supplementary service is requested by the served subscriber
Served subscriber: subscriber who has a provision of the UUS supplementary service and who activates the UUS
supplementary service. For service 1 and 2 the served subscriber is always the calling subscriber, for service 3 either the
calling or the called subscriber can be the served subscriber
Serving network: network of the served subscriber
User-to-User Information (UUI): information transferred by using the UUS supplementary service
ETSI

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3GPP TS 23.087 version 17.0.0 Release 17 7 ETSI TS 123 087 V17.0.0 (2022-04)
UUS Service: UUS services (Service 1, 2 and 3) are components of the UUS supplementary service. If the UUS
supplementary service is provided to a subscriber, he can handle the UUS services independently within a call
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ACM Address Complete Message
ANM ANswer Message
CON CONnect
CPG Call ProGress
IAM Initial Address Message
MS Mobile Station
REL RELease
SIFOC Send Info For Outgoing Call
SRI Send Routing Info
UUI User-to-User Information
UUS User-to-User Signalling
UUS1 User-to-User Signalling Service 1
UUS2 User-to-User Signalling Service 2
UUS3 User-to-User Signalling Service 3
Further GSM related abbreviations are listed in GSM 01.04.
4 General
The UUS supplementary service allows the transfer of UUI to a remote subscriber over the signalling channel in
association with a call to this subscriber. The UUS supplementary service is divided in Service 1, Service 2 and
Service 3.
The UUS Service 1 allows the transfer of UUI embedded within Call Control messages.
The UUS Service 2 allows the transfer of UUI with a specific User-to-user message after the served subscriber has
received an address complete indication and prior to the answer indication from the B-side.
The UUS Service 3 allows the transfer of UUI with a specific User-to-user message during an active call.
For the use of the UUS supplementary service in GSM PLMNs the support of UUS capabilities within the
inter-exchange signalling system (e.g. ISUP) is necessary. However this is out of scope of the present document.
4.1 Activation of UUS components
If any of the UUS Services 1, 2 or 3 shall be used within a call, the UUS capabilities have to be activated by the served
subscriber either when initiating this outgoing call (Service 1, 2 and 3) or during an established call (Service 3).
The UUS capabilities for a call can be requested by means of an implicit request or an explicit request. UUS Service 1
can be requested either implicitly or explicitly. Service 2 and 3 can only be requested explicitly.
4.1.1 Implicit request
The UUS1 service is activated implicitly by the presence of UUI in the set-up request from the mobile station. The
network shall transfer the received UUI transparently to the B-side. For the purpose of UUS service 1 implicitly
requested, no explicit check for the availability of UUS capabilities at the destination network has to be performed by
the originating network.
If the calling subscriber has UUS 1 provisioned and implicitly requested, the network shall transfer all UUI contained in
call control messages.
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3GPP TS 23.087 version 17.0.0 Release 17 8 ETSI TS 123 087 V17.0.0 (2022-04)
If the calling subscriber has UUS1 not provisioned, the contained UUI shall be discarded by the serving MSC. The call
shall be established without further restrictions.
The served subscriber shall not be informed whether the implicit request was successful or not.
4.1.2 Explicit request
Any UUS Service can be explicitly activated by the served subscriber within the set-up request initiating a mobile
originated call. In addition UUS Service 3 can be activated during an established call with a Facility message. A UUS
Service 1 request can be accompanied by appropriate UUI.
The network shall check for the availability of UUS capabilities for the call by passing the UUS request and the
eventually accompanied UUI to the remote side. If a UUS Service is available for the call an appropriate "UUS
provided" indication for this UUS Service shall be sent within the first backward message from the remote side.
A UUS Service shall not be activated for the call if a "UUS not provided" indication or no indication about the availability
of this UUS Service is received from the remote side.
Service 3 can be explicitly activated during an active call by both parties. This may lead to a collision of activation
requests. The collision of activation requests occurs when there is an outstanding request for service 3 and a subsequent
request is received from the remote user. The entity (user or network) that observes the collision shall reject the second
request with Facility message. This leads to the rejection of both requests.
4.1.3 UUS required option
As an option at call set-up the served subscriber can specify whether the requested UUS Service is required or not
required for the call. If service 1 is implicitly requested or if service 3 is requested during the call, it cannot be requested
as required.
If the served subscriber has specified that one of the UUS services is required for the call and this UUS service can not
be activated by the network, the call attempt of the served subscriber shall be cleared.
If the served subscriber has specified that one of the UUS services is not required for the call and this UUS service can
not be activated by the network, the call establishment shall be continued.
5 Handling of User-to-user signalling
5.1 Timers
UUS related timers are needed only for UUS service 3. Timers T1-UUS3, T3-UUS3 and T4-UUS3 are used only when
UUS service 3 is requested during an active call.
ETSI

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3GPP TS 23.087 version 17.0.0 Release 17 9 ETSI TS 123 087 V17.0.0 (2022-04)
Table 5.1: UUS Timers
Timer Name Value Run at Started Stopped Expiry
T1-UUS3 Remote 10s MSC of the UUS3 service request Answer to UUS3 Rejection of UUS3
network remote subscriber sent to the remote service request service is sent
control subscriber received from the toward the
remote subscriber requesting
network
T2-UUS3 UUS3 flow 10s MSC of the served The MSC receives When UUS3 service is Flow control
control subscriber and service acceptance deactivated parameter is
MSC of the incremented.
remote subscriber Timer is restarted.
Note 1.
T3-UUS3 Served 10s MS of the served UUS3 service request Acceptance to UUS3 Consider UUS3
subscriber subscriber sent to the requesting service received from service as not
control network requesting network activated
T4-UUS3 Serving 10s MSC of the served UUS3 service request Acceptance to UUS3 Rejection of UUS3
network subscriber sent to the remote service received from service is sent
control network remote network toward the served
subscriber

NOTE: If a user information message has been discarded due to flow control, a congestion control message shall
be sent to the user.
5.2 Information flows of UUS services
5.2.1 Service 1 (UUS1)
5.2.1.1 Flow control
No specific flow control is needed to restrict the amount of messages sent for either implicit or explicit UUS service 1
as the user-to-user information is transferred in call control messages.
ETSI

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3GPP TS 23.087 version 17.0.0 Release 17 10 ETSI TS 123 087 V17.0.0 (2022-04)
5.2.1.2 Information flows
Process MAF043 387_1(1)
User-to-user signalling Service 1
authorisations examinations (VLR)
Idle
Activation
UUS1
request
no
UUS1
provisioned
yes
set indication = Set indication =
UUS1 UUS1
available not available
continue
call
handling
Idle

Figure 5.2.1.2: MAF043
ETSI

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3GPP TS 23.087 version 17.0.0 Release 17 11 ETSI TS 123 087 V17.0.0 (2022-04)
5.2.1.2.1 Implicit activation
MSa MSCa VLRa GMSCb HLRb MSCb MSb
Set-up
SIFOC
UUI*
Complete call
IAM
SRI
UUI*
SRI ack
IAM
Set-up
UUI*
UUI*
ACM/ANM/CPG
Alert
ACM/ANM/CPG UUI
Alert UUI
UUI
UUI
Connect
...

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