6 Exceptions and clarifications for supplementary services

09.123GPPApplication of ISDN User Part (ISUP) Version 2 for the Integrated Services Digital Network (ISDN) - Public Land Mobile Network (PLMN) signalling interfacePart 1: Protocol specificationTS

Supplementary services are used according to ETS 300 356‑1 to ETS 300 356‑19 ([1] to [18]). 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 ETS 300 356‑2 to ETS 300 356‑19 ([1] to [18]) or ETS 300 542 to ETS 300 549 ([23] to [30]), 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 ETS 300 356‑1 to ETS 300 356‑19 ([1] to [18]), 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) should 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) should 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 to the new nature of address.

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

ETS 300 356‑3 [3] and ETS 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.

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

ETS 300 356‑5 [5] and ETS 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 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.

6.1.1.3 Terminal Portability (TP) supplementary service

ETS 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

ETS 300 356‑8 [8] applies.

NOTE: UUS1 explicit non-essential, UUS2 non-essential and UUS3 non-essential may be supported for calls that are forwarded back to the ISDN network.

6.1.1.5 Closed User Group (CUG) supplementary service

ETS 300 356‑9 [9] applies.

6.1.1.6 Subaddressing (SUB) supplementary service

ETS 300 356‑10 [10] applies.

6.1.1.7 Malicious Call Identification (MCID) supplementary service

ETS 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

ETS 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

ETS 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.

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

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))

ETS 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.

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

6.1.1.11 Call Hold (HOLD) supplementary service

ETS 300 356‑16 [15] applies.

6.1.1.12 Call Waiting (CW) supplementary service

ETS 300 356‑17 [16] applies.

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

ETS 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).

NOTE: Completion of Calls to Busy Subscriber is supported by the protocol, however the service is not provided for the GSM access.

6.1.1.14 Three party (3PTY) supplementary service

ETS 300 356‑19 [18] applies with the exception 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

ETS 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].