8 Interaction with other supplementary services

22.0913GPPExplicit Call Transfer (ECT) supplementary serviceStage 1TS

8.1 Calling Line Identification Presentation (CLIP)

If subscriber A originated the call between subscribers A and B, and subscriber B subscribes to CLIP, subscriber C’s identity shall be presented to subscriber B, subject to subscriber C’s line identification restrictions (see subclauses 8.2 and 8.4). If the connection has been established on the call between subscribers A and C before ECT is invoked, subscriber C’s identity shall be presented when ECT is invoked. If the connection is established on the call between subscribers A and C after ECT is invoked, subscriber C’s identity shall be presented when the connection on that call is established.

If subscriber A originated the call between subscribers A and C, and subscriber C subscribes to CLIP, subscriber B’s identity shall be presented to subscriber C, subject to subscriber B’s line identification restrictions (see subclauses 8.2 and 8.4) when ECT is invoked.

8.2 Calling Line Identification Restriction (CLIR)

If subscriber B originated the call between subscribers A and B, and subscriber B subscribes to CLIR, presentation of subscriber B’s identity to subscriber C shall be controlled by that subscription. Subscriber B’s serving network may also provide information on the cause of no CLI.

If subscriber C originated the call between subscribers A and C, and subscriber C subscribes to CLIR, presentation of subscriber C’s identity to subscriber B shall be controlled by that subscription. Subscriber C’s serving network may also provide information on the cause of no CLI.

8.3 Connected Line Identification Presentation (COLP)

If subscriber B originated the call between subscribers A and B, and subscriber B subscribes to COLP, subscriber C’s identity shall be presented to subscriber B, subject to subscriber C’s line identification restrictions (see subclauses 8.2 and 8.4). If the connection has been established on the call between subscribers A and C before ECT is invoked, subscriber C’s identity shall be presented when ECT is invoked. If the connection is established on the call between subscribers A and C after ECT is invoked, subscriber C’s identity shall be presented when the connection on that call is established.

If subscriber C originated the call between subscribers A and C, and subscriber C subscribes to COLP, subscriber B’s identity shall be presented to subscriber C, subject to subscriber B’s line identification restrictions (see subclauses 8.2 and 8.4) when ECT is invoked.

8.4 Connected Line Identification Restriction (COLR)

If subscriber A originated the call between subscribers A and B, and subscriber B subscribes to COLR, presentation of subscriber B’s identity to subscriber C shall be controlled by that subscription.

If subscriber A originated the call between subscribers A and C, and subscriber C subscribes to COLR, presentation of subscriber C’s identity to subscriber B shall be controlled by that subscription.

8.5 Call Forwarding Unconditional (CFU)

No impact.

8.6 Call Forwarding on mobile subscriber Busy (CFB)

Where a network supports the option to transfer a call for which the connection has been established to a subscriber C to which the connection has not yet been established, the transferred call will be forwarded to a forwarded-to subscriber D if the CFB condition at subscriber C (i.e. UDUB) applies.

For a call that is forwarded due to CFB after ECT is invoked, the sending of line identities to subscriber B and forwarded-to subscriber D respectively shall correspond to what is specified for the B and C subscribers in subclauses 8.1 through 8.4, i.e. replacing ‘subscriber C’ with ‘the forwarded-to subscriber D’ in the text.

8.7 Call Forwarding on No Reply (CFNRy)

The CFNRy timer at C is not restarted after the transfer has taken place.

Where a network supports the option to transfer a call for which the connection has been established to a subscriber C to which the connection has not yet been established, the transferred call will be forwarded to a forwarded-to subscriber D if the call forwarding no reply timer expires.

For a call that is forwarded due to CFNRy after ECT is invoked, the sending of line identities to subscriber B and forwarded-to subscriber D respectively shall correspond to what is specified for the B and C subscribers in subclauses 8.1 through 8.4, i.e. replacing ‘subscriber C’ with ‘the forwarded-to subscriber D’ in the text.

8.8 Call Forwarding on mobile subscriber Not Reachable (CFNRc)

No impact.

8.9 Call Waiting (CW)

No impact, any party may receive a CW indication before, during or after the calls are transferred.

NOTE: After execution of ECT the served subscribers access is free for receiving calls without a CW indication.

If subscriber A has one active, one held and one waiting call, then once ECT of the held and active calls has been successfully completed, subscriber A shall be offered the normal notification that there is a new call, as for a normal terminating call.

If the call to subscriber C meets the waiting state at C, the subscriber B shall be informed after successful transfer about the waiting status at subscriber C.

8.10 Call Hold (HOLD)

No impact, if either subscriber B or C have put their call to the served subscriber A on hold prior to the transfer, the resulting transferred call shall remain on hold by that subscriber. In this case the remote parties shall not be informed of the held state on the call.

8.11 Multi-party (MPTY) service

A served mobile subscriber who has invoked MPTY supplementary service is not allowed to invoke the ECT supplementary service.

This is due to the fact that the MPTY functionality can not be subject to call transfer at all.

Any of the remote parties is allowed to invoke ECT.

8.12 Closed User Group (CUG)

The two calls shall use the same closed user group for the transfer to be successful.

NOTE: Closed user group restrictions between subscribers will have been checked when the first call is established. Similarly, closed user group restrictions between subscribers will have been checked when established the second call.

8.13 Advice of Charge (AoC)

Served mobile subscriber:

– if call transfer is successfully accepted by the network, subscriber A will be disconnected, and therefore AoC processing at subscribers A Mobile Station will be stopped;

– for the combination AoC charging level and ECT, it is strongly recommended not to subscribe to both supplementary services at the same time.

Remote mobile subscriber:

– any AoC service at the remote sides will continue to calculate the charging information according to the original call.

8.14 Barring of All Outgoing Calls (BAOC)

No impact.

8.15 Barring of all Outgoing International Calls (BOIC)

No impact.

NOTE: If transfer occurs successfully at subscriber A, the barring programs at the remote subscribers cannot be checked again.

8.16 Barring of all Outgoing International Calls except those direct to the Home PLMN Country (BOIC-exHC)

No impact.

NOTE: If transfer occurs successfully at subscriber A, the barring programs at the remote subscribers cannot be checked again.

8.17 Barring of All Incoming Calls (BAIC)

No impact.

8.18 Barring of Incoming Calls when roaming outside the home PLMN country (BIC-Roam)

No impact.

8.19 Call Transfer (CT)

No impact.

The ECT supplementary service can be invoked simultaneously by the users on a call for which the connection has been established, but this is not regarded as a normal situation. The network will not be required to prevent this occurring, but likewise cannot guarantee that the indications supplied to the users involved will be sensible to those users. There can be more than one indication generated due to multiple invocations of the ECT supplementary service and the arrival of such indications is dependent on the timing of their invocation by the users involved in the call. The network shall transfer these indications when they are generated.

Therefore, both mobile subscribers (subscriber A and subscriber B) in a normal call, who have each subscribed to the ECT supplementary service, can simultaneous transfer the call. That is, if subscriber A and subscriber B are involved in a call on which the connection has been established, subscriber A can transfer the call to user C and subscriber B can transfer the call to user D.

NOTE: Mechanisms which prevent the ECT supplementary service from resulting in a connection which contains no subscriber able to terminate the call may result in rejection of simultaneous requests to invoke the ECT supplementary service by the subscribers involved in the call.