The mobile subscriber can request the status of the supplementary service and be informed if the service is provided to him/her. This procedure is illustrated in Figure 3.1
If the forwarding user selects the option that the calling user is not notified of the call forwarding, then the calling user shall receive no forwarding notification, and the calling user shall not receive the connected user's identity when the call is answered, unless the calling user has override capability.
The following Mobile Additional Functions have been identified for the PLMN:
Determination of the connected line identification presentation subscription
The ability of a PLMN component to determine whether the supplementary service is provisioned for the mobile subscriber. See Figure 3.2
Determination of the connected party number for offering to the calling party
The ability of a PLMN component to determine and to forward the connected line identity and related indications to the calling party. See Figure 3.3
Location: originating MSC.
Interaction of connected line identification presentation with the call forwarding supplementary services
The ability of a PLMN component to determine the presentation indicator of the connected party number after invocation of a call forwarding service. See Figure 3.4
Location: forwarding MSC.
The information flow is shown in Figure 3.5
COLP may have the following logical states (refer to TS 23.011
for an explanation of the notation):
The HLR shall store the logical state of COLP (which shall be one of the valid states listed above) on a per subscriber basis.
The HLR shall also store the subscription option "override category"
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 COLP. 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.
If the provisioning state for COLP is "Provisioned"
then, when the subscriber registers on a VLR, the HLR shall send that VLR information about the logical state of COLP. The HLR shall send the override category if the VLR is in the HPLMN country. The HLR may send the override category if the VLR is outside the HPLMN country.
If the logical state of COLP or the override category is changed while a subscriber is registered on a VLR then the HLR shall inform the VLR of the new logical state of COLP. If the override category is changed and the provisioning state of COLP is "Provisioned"
then the HLR shall inform the VLR about the new override category when the VLR is in the HPLMN country. The HLR may inform the VLR about the new override category when the VLR is outside of the HPLMN country.
For COLP, the VLR shall store the service state information and override category received from the HLR.
If not received from the HLR (case of roaming outside the HPLMN country), the override category shall be set to the default value "no"
Handover will have no impact on the control procedures and the operation of the service.