2 Calling Line Identification Restriction (CLIR)

04.813GPPLine Identification supplementary servicesStage 3TS

2.1 Normal Operation

When calling line identification restriction is applicable, the originating network provides the destination network with a notification that the calling party’s ISDN number, with possible additional address information, is not allowed to be presented to the called party.

If the called mobile user subscribes to calling line identification presentation and the calling party has calling line identification restriction applied, the called mobile party shall receive the presentation indicator showing "presentation restricted" in the calling party BCD field of the SETUP message, see figure 1.1. In this case, the calling party’s number (digits) will not be sent towards the called subscriber.

2.2 Requesting presentation of CLI

When the CLIR presentation mode is temporary (presentation restricted), it is possible for the subscriber to present his CLI on a per call basis. The MS shall send a CLIR suppression information element to the network.

If the subscriber tries to override CLIR (i.e. requests that the CLI is displayed), when he has subscribed to permanent mode a NotifySS shall be sent to the MS in order to inform that the override has not been performed and the call set-up shall continue.

MSa Network

SETUP

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CLIR suppression

FACILITY

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Facility (Invoke = NotifySS (CLIR, CLIR Suppression Rejected))

Figure 2.1: Requesting presentation of CLI

2.3 Requesting restriction of CLI presentation

When the CLIR presentation mode is temporary (presentation allowed), it is possible for the subscriber to restrict the CLI on a per call basis. The MS shall send a CLIR invocation information element to the network.

If the subscriber has not subscribed to CLIR and tries to invoke CLIR (i.e. requests that the CLI is not displayed), the SETUP shall be rejected. The MS and the network shall act in accordance with GSMĀ 04.08 network initiated call clearing procedure, see figure 2.2.

MSa Network

SETUP

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CLIR invocation

DISCONNECT/RELEASE/RELEASE COMPLETE

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Cause #50 (Facility not subscribed, diagnostic = CLIR not subscribed)

Figure 2.2: Requesting restriction of CLI presentation

2.4 Interrogation

Data request

The mobile subscriber can request the data of the supplementary service.

If the service is not provisioned the network shall sent a return result including the SS-Status parameter.

If the service is provisioned the network shall sent a return result including the SS-Status and the CLI Restriction Option parameters.

MSa Network

REGISTER

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Facility (Invoke = InterrogateSS (CLIR))

RELEASE COMPLETE

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Facility (Return Result = InterrogateSS (SS-Status, CLI Restriction Option))

RELEASE COMPLETE

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Facility (Return Error (Error))

RELEASE COMPLETE

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Facility (Reject (Invoke_problem))

Figure 2.3: Interrogation of calling line identification restriction

2.5 Activation, deactivation, registration and erasure

Activation, deactivation, registration and erasure of the supplementary service calling line identification restriction are not applicable.