The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

• References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.

Abbreviations used in the present document are listed in TR 21.905.

Activation, deactivation, registration, erasure, interrogation and invocation are defined independently from a particular supplementary service. Whether they are applicable to a particular supplementary service or not is defined in the corresponding 3GPP TS 23.08x and 23.09x series. Activation, deactivation, registration, erasure and invocation are applicable for CS domain. For PS domain o nly invocation of call barring of SMS is applicable. The invocaZtion of a supplementary service is executed as described in the corresponding stage 2 description and always includes an MSC and a location register for CS domain and an SGSN for PS domain. When an MSC receives a request for either activation/deactivation or registration/erasure or an interrogation, it invokes one of the following procedures. The MSC then can:

• contact only the current VLR (e.g. interrogation of a call forwarding conditional supplementary service);
• contact only the HLR (e.g. interrogation of the supplementary service call forwarding unconditional);
• contact the HLR, after which the HLR updates the VLR (e.g. registration of a forwarding number for a conditional call forwarding supplementary service).

Which of the above listed procedures is applied for a call independent supplementary service operation is described in the corresponding 3GPP TS 23.08x and 23.09x series. Successful activation, deactivation, registration and erasure change the service state at the HLR. These transitions (if applicable to a particular service) are defined in the 3GPP TS 23.08x and 23.09x series. Note that the HLR may also change the service state due to "HLR Induction" (see clause 2.1.1). In connection with supplementary service operations the served subscriber or remote subscribers may get notifications from the network. . If an SGSN receives a request for registration, erasure, activation, deactivation, interrogation or change of password, it shall return an error to the MS.

A request for registration, erasure, activation, deactivation or interrogation of a supplementary service always refers to a basic service group. The basic service group may be either an elementary basic service group (defined in TS 22.004) or a collective basic service group (defined in TS 22.030). The following text and Figure 2.1 describe the general handling of call independent SS procedures in the destination entity with respect to basic service groups.

• The VLR or HLR (i.e. the destination entity) shall check the received request for general problems (see Figure 2.1-2 sheet 2 and Figure 2.1-3 sheet 3).
• In case of general error the procedure shall be terminated by sending an error towards the MS (see Figure 2.1-1 sheet 1).
• If there is no general problem, the HLR or VLR shall split the received basic service group (BSG) into elementary basic service groups (EBSG) and continue with separate handling of each elementary basic service group (see Figure 2.1-1 sheet 1).
  Note that the received basic service group may be an elementary basic service group. In this case splitting is not required.
  • Elementary basic service groups shall be ignored if:
  • there is no basic service provisioned in the group; or
  • the supplementary service is not applicable for any basic service within this elementary basic service group;
    (see Figure 2.1-4 sheet 4).
  Note that in case the SS is either not provisioned or all the elementary basic service groups were ignored a general error will be returned (see above).

For interrogation the following handling continues (see Figure 2.1-4 sheet 4):

• For all other elementary basic service groups the information requested will be returned to the MS and the procedure is terminated.

For registration/erasure and activation/deactivation the following handling continues (see Figure 2.1-4 sheet 4):

• For all other elementary basic service groups the requested procedure will either be executed or rejected due to interaction with other supplementary services.
• If the request cannot be accepted for any of these elementary basic service groups due to interaction, the corresponding error will be returned and the procedure is terminated.
• If the request was executed for all of these elementary basic service groups an acknowledgement is returned towards the MS and the procedure is terminated.
  Note that this acknowledgement will include the same basic service group as received in the request.
• In case the request is accepted for some but not for all of these elementary basic service groups, partial acceptance will be signalled towards the MS and the procedure will be terminated.

The return errors for supplementary service operations and applicability of these errors are defined in TS 24.080. Detailed description of call independent handling for a specific supplementary service is described in 3GPP TS 23.08x and 23.09x series of technical specifications.

When an individual teleservice code or bearer service code is sent by an MS instead of an elementary basic service group the network shall treat such a request as a request for the corresponding elementary basic service group. The response to such a request shall include the elementary basic service group code of this basic service code if this is required by the protocol or application.

Some supplementary services can be subscribed with the option "control of supplementary service by subscriber using password" as described in the corresponding 3GPP TS 23.08x and 23.09x series of technical specifications. This option is applicable only for the CS domain. These services are referenced in the following as protected supplementary services. The password is stored in the HLR only. It has to be memorised by the network, if a wrong password has been used. Therefore, the HLR stores the value of the Wrong Password Attempts counter (WPA). If a password check is done with an incorrect password, the WPA is incremented by one. If a password check is passed, WPA is set to zero. If WPA exceeds the value three, the subscription option "control of supplementary service" is set to "by the service provider". This makes registration of password and activation or deactivation of protected supplementary services impossible (see TS 22.004). When the service provider registers a password, the WPA is set to zero. When an attempt to perform an operation requiring a password is received by the network, the network has to check whether the requesting subscriber has subscribed to the option "control of supplementary service by subscriber using password". This is shown in Figure 3.1 (function PW1). If this option has the value "by the service provider" the WPA has to be checked. When WPA exceeds three, then more than three attempts with a wrong password have been made and the appropriate message will be sent to the user. If the value of WPA is less than or equal to three, then the subscriber has not subscribed to "control of supplementary service by subscriber using password". When a password is supplied, it has to be checked, whether it is identical to the one stored. If this applies, then WPA is reset to zero. Otherwise WPA is incremented by one and dependent of the value of the counter, the network shall request the password again, or shall send and error message and update the subscription option as shown in Figure 3.2 (function PW2). After the input of a wrong password more than three consecutive times, the only possibility to reset the Wrong Password Attempts counter (WPA) is, to register a new password by the service provider. Figure 3.3 and Figure 3.4 show the procedures executed by the network in order to check the format (function PW3) and to check the new password (function PW4).

If the served mobile subscriber at provision time has selected the subscription option "control of supplementary service by subscriber using password", the service provider has to register a password at provision time. Furthermore the served mobile subscriber can change the password by an appropriate control procedure at any time. The control procedure consists of three steps: first, the old password has to be provided; secondly, the new password has to be given, after which it has to be verified by providing it once more (see Figure 3.5). If the served mobile subscriber at provision time has selected the subscription option "control of supplementary service by the service provider" an attempt to register a password will be denied and the served mobile subscriber should receive a notification. The subscriber can register a new password, thus causing the previous registration to be overridden (see Figure 3.5).

If the served mobile subscriber at provision time has selected the subscription option "control of supplementary service by subscriber using password" the supplementary service is activated only if the subscriber provides the correct password to the network. If the served mobile subscriber at provision time has selected the subscription option "control of supplementary service by the service provider", the supplementary service cannot be activated by the subscriber. The activation has to be performed by the service provider. An attempt to activate the service will be denied and the served mobile subscriber should receive a notification. If the served mobile subscriber at provision time has selected the subscription option "control of supplementary service by subscriber using password", and if a wrong password is entered to activate the service the supplementary service will not be activated and the served mobile subscriber is notified. The information flow for activation of a protected supplementary service is shown in Figure 3.6.

The procedure for activation, described in clause 3.3, is valid also correspondingly for deactivation. The information flow for deactivation of protected supplementary service is shown in Figure 3.7.