4 Call Deflection (CD)

04.723GPPCall Deflection (CD) supplementary serviceStage 3TS

4.1 Normal operation

4.1.1 Served mobile subscriber side

The served mobile subscriber may invoke the call deflection supplementary service if an incoming call is offered. According to GSM 02.72 this may happen as an automatic response from the mobile station if the call is offered or as the result of a subscriber action.

The mobile station shall invoke the call deflection supplementary service by initiating call clearing with a DISCONNECT message including the call deflection request (refer to figure 4.1). The call deflection request shall contain the DeflectedToNumber which may be accompanied by a DeflectedToSubAddress.

The MS may invoke the call deflection supplementary service at every time after call confirmation until the call is accepted (refer to GSM 04.08). If the network accepts the call deflection request, it shall continue call clearing. The result indication shall be returned to the mobile station in the RELEASE message.

If the network cannot accept the call deflection request, it shall continue call clearing. The corresponding error indication shall be returned to the mobile station in the RELEASE message. Error values are specified in GSM 04.80.

During the call deflection request the MS shall run a timer TCD (T305). This timer is started when the call deflection request is sent and stopped when a response is received from the network. If this timer expires the MS shall assume that the call deflection request has failed, locally release the invokeID, inform the user of the failure and continue call clearing as defined in GSM 04.08.

MS Network

SETUP

<————————————————————————————————————————

CALL CONFIRMED

————————————————————————————————————————>

·

·

·

DISCONNECT

————————————————————————————————————————>

Facility (Invoke = CallDeflection (DeflectedToNumber, DeflectedToSubAddress))

RELEASE

<————————————————————————————————————————

Facility (Return result)

RELEASE

<- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

Facility (Return error (Error))

RELEASE

<- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

Facility (Reject = (Invoke Problem))

RELEASE COMPLETE

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Figure 4.1: Call deflection invocation for an incoming call

4.1.2 Deflected-to mobile subscriber side

As for the call forwarding supplementary services the deflected-to mobile subscriber will receive a NotifySS operation containing the SS Notification indicating that the incoming call is a forwarded call. When available, the SS Code of the Call Deflection supplementary service is included, see figure 4.2.

When multiple diversions occurs the value of the SS Code shall relate to the last invoked diversion service.

In addition the deflected-to subscriber will receive the redirecting party BCD number and optionally, a redirecting party subaddress.

The redirecting party BCD number information element is made up of a number of information units as defined in GSM 04.08.

In addition to or instead of the redirecting party’s digits, the subscriber may be given the following information:

– screening indicator;

– presentation indicator.

Indicator values are given in GSM 04.08.

The redirecting party subaddress information element is made up of a number of information units as defined in GSM 04.08.

MS Network

SETUP

<————————————————————————————————————————

Facility (Invoke = NotifySS (CD, SS-Notification)),

Redirecting party BCD number (screening indicator, presentation indicator, redirecting party digits),

Redirecting party subaddress

Figure 4.2: Notification to the forwarded to mobile subscriber
that the incoming call is a forwarded call

4.1.3 Calling mobile subscriber side

As a subscription option, the served mobile subscriber can request that the calling mobile subscriber receives a NotifySS operation containing the SS Notification indicating that the call has been deflected. When available, the SS Code of the call deflection supplementary service is included, see figure 4.3.

MS Network

SETUP

————————————————————————————————————————>

FACILITY

<————————————————————————————————————————

Facility (Invoke = NotifySS (CD, SS-Notification))

Figure 4.3: Notification to the calling mobile subscriber that the call is forwarded

Annex A (informative):
Status of GSM 04.72

Status
of
Technical Specification GSM 04.72: stage 3 of Call Deflection

Date

Version

Comments

No Phase 1 and no Phase 2 version

May 1998

0.0.0

first draft at the SMG3-WPB meeting in Basingstoke, 11-15 May 1998

May 1998

0.1.0

Incorporation of comments during the SMG3-WPB meeting in Basingstoke

August 1998

0.2.0

presented at the SMG3-WPB meeting in Stuttgart, 10-14 August 1998

August 1998

0.2.1

clean version 0.2.0 to SMG3 September 1998 in Bonn

October 1998

1.0.0

to SMG#27 for information

October 1998

1.1.0

presented at the SMG3-WPB meeting in Chicago, 26-30 October 1998

January 1999

1.2.0

presented at the SMG3-WPB meeting in Sophia Antipolis,
11-15 January 1999

January 1999

2.0.0

presented at the SMG#28 for approval

February 1999

7.0.0

TS approved by SMG#28

October 2001

7.0.1

Editorial

Text and figures: WinWord 6.0
Stylesheet: etsiw_70.dot
Rapporteur: Steffen Habermann (T-Mobil)