6 Exceptions and clarifications for supplementary services

09.143GPPApplication of ISDN User Part (ISUP) Version 3 for the Integrated Services Digital Network (ISDN) - Public Land Mobile Network (PLMN) signalling interfacePart 1: Protocol specificationTS

Supplementary services are used according to EN 300 356‑1 to EN 300 356‑20 ([1] to [19]). When considering supplementary services, there exists a symmetry about this interface although the ISDN services may not be the same as the PLMN services. For each service supported by EN 300 356‑2 to EN 300 356‑20 ([1] to [19]) or ETS 300 542 to ETS 300 549 ([23] to [30]) and TS 101 283([31]), the operation of the service in each direction needs to be considered. Supplementary services supported by the interface but not by one of the connected networks shall be handled according to EN 300 356‑1 to EN 300 356‑20 ([1] to [19]), i.e. the gateway concerned acts like an international gateway.

Exceptions and clarifications for the coding are described in table D.3, unless otherwise stated.

6.1 Considerations on ISDN supplementary services

6.1.1 Handling of number parameters related to supplementary services

The following text applies when referenced for the appropriate parameters:

Number parameters related to supplementary services sent across the ISDN-PLMN interface shall have the following coding of the nature of address indicator:

National significant number (000 0011) shall be used in the following cases:

– for a number allocated to a fixed access when the fixed access, the sending gateway and the receiving gateway are in the same country;

– for a number allocated to an MS registered in its HPLMN when the MS, the sending gateway and the receiving gateway are in the same country.

International number (000 0100) shall be used for all other cases.

If the gateway has to modify a parameter to satisfy the above requirement, it shall modify the nature of address indicator and modify the number in accordance with the new nature of address.

6.1.1.1 Calling Line Identification Presentation/Restriction (CLIP/CLIR) supplementary services

EN 300 356‑3 [3] and EN 300 356‑4 [4] apply with the exceptions below:

Calling Party Number and Generic Number:

Handling of calling party number and the appropriate generic number shall be made according to subclause 6.1.1.

For mobile originated calls the calling line identity is mapped into the calling party number parameter.

If the Generic Number parameter with a number qualifier set to “additional calling party number” is received in a PLMN then the calling party number parameter shall be discarded by the mobile access.

The PLMN shall not check for consistency in the screening indicators of the calling party number and the additional calling party number.

Actions at the Mobile gateway exchange when supporting transfer of calling party number and generic number parameters via MAP interfaces:

The support of transfer of calling party number and generic number parameters via MAP interfaces shall have no impact on the actions to be performed at the mobile gateway exchange (GMSC) for the transfer of information relating to the CLIP and CLIR supplementary services on the ISUP interface.

The following actions shall be performed at the GMSC for the mapping of calling party number and generic number parameters to the MAP C interface:

The GMSC shall transfer neither the calling party number nor the generic number parameter to the MAP interface if the presentation indicator of the received calling party number parameter is set to “address not available“.

The GMSC shall convert the calling party number conveyed in the calling party number parameter to an international number (if necessary) and set the nature of address indicator to “international number”. The address presentation restricted indicator and the screening indicator shall be transferred transparently.

If the generic number parameter is received and its number qualifier indicates “additional calling party number” and the numbering plan indicator is coded “ISDN (Telephony) numbering plan (Recommendation E.164)”, then the generic number parameter shall be treated in the same manner as the calling party number parameter.

The generic number parameter shall not be mapped if its number qualifier indicates “additional calling party number” and the screening indicator is coded “user provided, verified and failed”.

The address presentation restricted indicator of the generic number parameter shall be set to the same value as the address presentation restricted indicator of the calling party number parameter ("presentation restricted" or "presentation allowed").

6.1.1.2 Connected Line Identification Presentation/Restriction (COLP/COLR) supplementary services

EN 300 356‑5 [5] and EN 300 356‑6 [6] apply with the exceptions below:

Connected Number and Generic Number:

Handling of connected number and the appropriate generic number shall be made according to subclause 6.1.1. For mobile terminated calls the connected line identity is mapped into the connected number parameter. If the Generic Number parameter with a number qualifier set to “additional connected number” is received in a PLMN then the connected number parameter shall be discarded by the mobile access. The PLMN shall not check for consistency in the screening indicators of the connected number and the additional connected number.

6.1.1.3 Terminal Portability (TP) supplementary service

EN 300 356‑7 [7] applies.

NOTE: Terminal Portability is supported by the protocol, however the service is not provided for the GSM access.

6.1.1.4 User-to-User Signalling (UUS) supplementary service

EN 300 356‑8 [8] applies.

NOTE: The maximum length of the user-user parameter of the setup message at the GSM access is restricted to 35 octets. When a GSM PLMN receives a longer user-to-user information element in the IAM message the User-to-user information element will be discarded without indication.

6.1.1.5 Closed User Group (CUG) supplementary service

EN 300 356‑9 [9] applies.

6.1.1.6 Subaddressing (SUB) supplementary service

EN 300 356‑10 [10] applies.

6.1.1.7 Malicious Call Identification (MCID) supplementary service

EN 300 356‑11 [11] applies with the exceptions below:

Calling Party Number and Generic Number:

Handling of calling party number and the appropriate generic number shall be made according to subclause 6.1.1.

NOTE: Malicious Call Identification is supported by the protocol, however the service is not provided for the GSM access.

6.1.1.8 Conference call, add-on (CONF) supplementary service

EN 300 356‑12 [12] applies with the exception below:

Notification messages may be sent from the PLMN to the ISDN according to ETS 300 545 [26].

NOTE: Conference call is supported by the protocol, however the service is not provided for the GSM access. The corresponding service in GSM is the multiparty service defined by the GSM standards.

6.1.1.9 Explicit Call Transfer (ECT) supplementary service

EN 300 356‑14 [13] applies with the exceptions below:

Call Transfer Number:

Handling of call transfer number shall be made according to subclause 6.1.1.

6.1.1.10 Diversion supplementary services (Call Forwarding Unconditional (CFU) / Call Forwarding on Busy (CFB) / Call Forwarding on No Reply (CFNR) / Call Deflection (CD))

EN 300 356‑15 [14] applies with the exceptions below:

Original Called Number, Redirecting Number and Redirection Number:

Handling of original called number, redirecting number and redirection number shall be made according to subclause 6.1.1.

6.1.1.11 Call Hold (HOLD) supplementary service

EN 300 356‑16 [15] applies.

6.1.1.12 Call Waiting (CW) supplementary service

EN 300 356‑17 [16] applies.

6.1.1.13 Completion of Calls to Busy Subscriber (CCBS) supplementary service

EN 300 356‑18 [17] applies with the exception below:

If the GMSC has the knowledge that the CCBS service is not supported the diagnostics in the Release message will be set to indicate "CCBS not possible" (for cause values 17 or 34).

6.1.1.14 Completion of Calls on No Reply (CCNR) supplementary service

EN 300 356‑20 [19] applies with the exception below:

NOTE: Completion of Calls on No Reply is supported by the protocol, however the service is not provided for the GSM access.

6.1.1.15 Three party (3PTY) supplementary service

EN 300 356‑19 [18] applies with the exceptions below:

Notification messages may be sent from the PLMN to the ISDN according to ETS 300 545 [26].

NOTE: Three party is supported by the protocol, however the service is not provided for the GSM access. The 3PTY service can be a part of the multiparty service as defined by the GSM standards.

6.2 Considerations on GSM unique supplementary services

6.2.1 Call Forwarding on Mobile Subscriber Not Reachable (CFNRc) supplementary service

EN 300 356‑15 [14] applies with the exceptions below:

Original Called Number, Redirecting Number and Redirection Number:

Handling of original called number, redirecting number and redirection number shall be made according to subclause 6.1.1. For calls that have been redirected (because of mobile subscriber not reachable) via the GSM-system, the Redirecting Reason shall be set to Mobile Subscriber Not Reachable.

6.2.2 Advice of Charge (AoC) supplementary service

No impact on the ISDN-PLMN- interface. The service is described in ETS 300 547 [28].

6.2.3 Call Barring (CB) supplementary service

No impact on the ISDN-PLMN interface. The service is described in ETS 300 548 [29].

6.2.4 Unstructured Supplementary Service Data (USSD)

No impact on the ISDN-PLMN interface. The service is described in ETS 300 549 [30].

6.2.5 Calling Name Presentation supplementary service (CNAP)

No impact on the ISDN-PLMN interface. The service is described in TS 101 395 [XX].

6.2.6 Multiple Subscriber Profile (MSP) supplementary service

No impact on the ISDN-PLMN interface. The service is described in TS xxx xxx [xx].