If the originating party has calling line identification restriction provisioned and it is impossible to indicate to the terminating network (due to interworking) that the number should not be presented to the terminating party, the calling line identity shall not be delivered to the terminating network.
If the subscriber has calling line identification restriction provisioned in permanent mode, the originating party's CLI shall not be presented to the terminating party (i.e. the terminating MS or TE), unless the terminating party has calling line identification presentation provisioned with the subscription option "override category" set (see clause 1).
A subscriber can have calling line identification restriction provisioned in temporary mode with one of two default values: presentation restricted or presentation allowed.
If the default value is set to presentation restricted, the default handling is not to present the originating party's CLI to the terminating party (i.e. the terminating MS or TE).
However, it is possible for the originating subscriber to present his CLI to the terminating party. The originating subscriber must indicate during call set up that the CLI must be presented to the terminating party. This procedure is illustrated in Figure 2.1.
If the default value is set to presentation allowed, the default handling is to present the originating party's CLI to the terminating party (i.e. the terminating MS or TE).
However, it is possible for the originating subscriber to restrict presentation of his CLI to the terminating party. The originating subscriber must indicate during call set up that CLI presentation must be restricted. This procedure is illustrated in Figure 2.2.
The following Mobile Additional Functions have been identified for the PLMN:
MAF003
Determination of the calling line identification restriction subscription
The ability of a PLMN component to determine whether the supplementary service is provisioned for the mobile subscriber. See Figure 2.4.
Location: VLR.
MAF004
Determination of the calling party number for offering to the called party
The ability of a PLMN component to determine and to forward the calling line identity and related indications to the called party. See Figure 2.5.
Location: originating MSC.
CLIR may have the following logical states (refer to TS 23.011 for an explanation of the notation):
Provisioning State
Registration State
Activation State
HLR Induction State
(Not Provisioned,
Not Applicable,
Not Active,
Not Induced)
(Provisioned,
Not Applicable,
Active and Operative,
Not Induced)
The HLR shall store the logical state of CLIR (which shall be one of the valid states listed above) on a per subscriber basis.
The HLR shall also store the subscription option "presentation mode" on a per subscriber basis.
This parameter takes one of the following values:
The following Figure shows the successful cases of transition between the applicable logical states of CLIR. The state changes are caused by actions of the service provider.
Note that error cases are not shown in the diagram as they normally do not cause a state change. Additionally, some successful requests may not cause a state change. Hence they are not shown in the diagram.
When the subscriber registers on a VLR, the HLR shall send that VLR information about the logical state of CLIR and the presentation mode.
If the logical state of CLIR or the presentation mode is changed while a subscriber is registered on a VLR then the HLR shall inform the VLR of the new logical state of CLIR and (if the provisioning state is "Provisioned") the new presentation mode.
The VPLMN needs to distinguish three cases in order to meet data privacy requirements in an environment where support of CLIP and CLIR is optional:
the HPLMN supports CLIR, and CLIR is provisioned for the subscriber;
the HPLMN supports CLIR, but CLIR is not provisioned for the subscriber;
the HPLMN does not support CLIR.
In case a) the VPLMN must apply the CLIR subscription as indicated by the data sent by the HPLMN.
In case b) the VPLMN must not apply CLIR.
In case c) the VPLMN must apply an implicit CLIR subscription.
To allow the VPLMN to make this distinction, the HLR and VLR behave as follows:
If the HLR supports CLIR, but CLIR is not provisioned for the subscriber, the HLR shall inform the VLR that CLIR is not provisioned.
If the VLR supports CLIR, but the HLR does not support CLIR, the VLR shall behave in the same way as if CLIR (temporary (presentation restricted)) was provisioned for the subscriber, i.e. the calling line identity shall not be displayed to the called subscriber unless the called subscriber has CLIR override capability. When interrogating the service status the subscriber shall be informed that CLIR (temporary (presentation restricted)) is provided to him and is active.