4 CTS supervising management procedures

04.573GPPGSM Cordless Telephony System (CTS), (Phase 1) CTS CTS supervising system Layer 3 SpecificationTS

4.1 General

CTS supervising management procedures include the functions related to the management of the CTS system by the CTS operator. These functions are based on :

– radio control: the control of the radio parameters used on the CTS radio interface

– security control: including subscription checking, CTS authentication (the authentication of the CTS subscriber identity by the CTS Service Node and the authentication of the signature issued by the Service Node by the Fixed Part), GSM authentication (authentication of the Mobile Station by the GSM operator through the Service Node) and administrative data management.

All the CTS supervising procedures can only be performed if a CTS-FP/CTS-SN connection has been established between the fixed part and the service node. If no CTS-FP/CTS-SN connection is currently established, the CTS supervising layer has to initiate such establishment.

As in most cases, the CTS-SN has no means of addressing the CTS-FP, it is assumed that the CTS procedures can only be started by the fixed part. CTS procedures initiated by the Service Node follow a procedure started by the Fixed Part.

4.2 CTS-SPM procedures

All CTS-SPM procedures can only be initiated if a CTS-FP/CTS-SN connection is established.

The procedures initiated by the Fixed Part are:

– CTS-SPM initialisation procedure

– CTS-SPM enrolment procedure

– CTS-SPM de-enrolment indication procedure

– CTS-SPM operation data update procedure

The procedures initiated by the Service Node (following a procedure started by the Fixed Part) are:

– CTS-SPM de-initialisation procedure

– CTS-SPM de-enrolment procedure

– CTS-SPM FP authentication procedure

– CTS-SPM MS authentication procedure

– CTS-SPM signature mode setting procedure

– CTS-SPM operation data inform procedure

4.3 CTS-SPM states

4.3.1 CTS-SPM states at the Fixed Part

  1. IDLE

The CTS-SPM state is not active.

  1. WAIT FOR CTS-FP/CTS-SN CONNECTION

The CTS-SPM has requested the establishment of a CTS-FP/CTS-SN connection.

  1. CTS-SPM CONNECTION ACTIVE

A CTS-SPM connection is active. Only one CTS-SPM connection can be active at a time.

  1. CTS-SPM INITIALISATION INITIATED

The CTS-FP initialisation procedure has been started at the Fixed Part.

  1. CTS-SPM ENROLMENT INITIATED

The enrolment procedure has been started at the Fixed Part.

  1. CTS-SPM OPERATION DATA UPDATE INITIATED

The operation data update procedure has been started at the Fixed Part.

Only one CTS-SPM connection can be active at a time on the Fixed Part. Nevertheless, an active CTS-SPM connection does not preclude having active CTS-RR and CTS-MM active connection on the CTS radio interface.

4.3.2 CTS-SPM states at the Service Node

  1. CTS-SPM DE-INITIALISATION INITIATED

The CTS-FP de-initialisation procedure has been started by the Service Node.

  1. CTS-SPM DE-ENROLMENT INITIATED

The de-enrolment procedure has been started by the Service Node.

  1. CTS-SPM INFORMATION DATA INITIATED

The information data request procedure has been started by the Service Node.

  1. CTS-SPM FP AUTHENTICATION INITIATED

The FP authentication procedure has been started by the Service Node.

  1. CTS-SPM MS AUTHENTICATION INITIATED

The MS authentication procedure has been started by the Service Node.

4.4 CTS-SPM common procedures

4.4.1 CTS-FP initialisation procedure

The purpose of the CTS-FP initialisation procedure is to provide the fixed part with the necessary data to enable CTS service.

The CTS-FP initialisation procedure is always initiated by the CTS-FP.

4.4.1.1 CTS-FP initialisation initiation

The fixed part initiates the CTS-FP initialisation procedure by sending a CTS-SPM INITIALISATION REQUEST message to the CTS-SN and starts the timer T_init_FP.

The CTS-SPM INITIALISATION REQUEST message specifies the fixed part identity, and the classmark of the fixed part.

The CTS-SPM INITIALISATION REQUEST message is sent on the CTS-FP/CTS-SN interface following a CTS-FP/CTS-SN connection initiated by the CTS fixed part.

4.4.1.2 CTS-FP initialisation completion

If the CTS-FP initialisation can be performed, the service node shall send a CTS-SPM INITIALISATION ACCEPT to the fixed part. This message includes the necessary radio parameters to enable operation on the CTS interface. These data are associated to timers that are also sent in the message. The validity period (Tval) timer indicates the maximum duration where those data should be used. The recall period (Trecal) requires the fixed part to contact the service node on a regular basis. The recall period should enable the fixed part to update the necessary data before the validity period expires. If Tval and Trecal are not included in the CTS-SPM INITIALISATION ACCEPT message, their values are considered as being infinite.

Upon reception of this message, the fixed part stops the timer T_init_FP.

The service node shall send a CTS-SPM INITIALISATION REJECT if the rights are not verified.

When, the fixed part has received and accepted the necessary data in order to operate, it sends a CTS-SPM INITIALISATION COMPLETE to the service node.

4.4.2 CTS enrolment procedure

The enrolment of a mobile station onto a fixed part is the procedure by which a mobile and a fixed part are made known to each other in order that the CTS service can be provided to the mobile station. This procedure can be performed under the control of the CTS operator depending on the information downloaded by the operator at subscription setting. The enrolment procedure performed locally between the mobile station and the fixed part is described in GSM 04.56.

If required by the CTS operator, the additional CTS-SPM enrolment procedure should be performed.

The CTS-SPM enrolment procedure is initiated by the fixed part following a successful first part local enrolment procedure.

4.4.2.1 CTS-SPM enrolment initiation

The fixed part initiates the CTS-SPM enrolment procedure by sending the message CTS-SPM ENROLMENT REQUEST message and starting a timer T_enrol_FP.

The CTS-SPM ENROLMENT REQUEST message specifies the fixed part identity and the mobile identity.

4.4.2.2 CTS enrolment completion

If the service node agrees to enrol the mobile onto the fixed part, the service node sends a CTS-SPM ENROLMENT ACCEPT message. This message may include an enrolment validity time; if this information element is not included in the message, the enrolment validity period is considered as being infinite.

Similarly, the service node shall send a CTS-SPM ENROLMENT REJECT if the request cannot be granted with the reject cause. Upon reception of CTS-SPM ENROLMENT ACCEPT or CTS-SPM ENROLMENT REJECT message, the fixed part stops timer T_enrol_FP.

4.4.3 CTS operation data update procedure

The purpose of the CTS operation data update procedure is to provide the fixed part with the necessary data to operate. Before performing the operation data update procedure the fixed part has to be initialised.

This procedure is launched by the fixed part at the expiry of timer Trecal. The duration of Trecal is defined by the service node during the CTS-FP initialisation procedure.

4.4.3.1 CTS operation data update initiation

The fixed part initiates the CTS operation data update procedure by sending the message CTS-SPM OPERATION DATA REQUEST message and starting timer T_opdata_FP.

4.4.3.2 CTS operation data update completion

The service node sends the required data in a CTS-SPM OPERATION DATA DELIVER message. Upon reception of this message the fixed part stops timer T_opdata_FP.

The sent operation data are associated to 2 timers. The validity period (Tval) timer indicates the maximum duration where those data should be used. The recall period (Trecal) requires the fixed part to contact the service node on a regular basis. The recall period should enable the fixed part to update the necessary data before the validity period expires. If Tval and Trecal are not included in the CTS-SPM OPERATION DATA DELIVER message, there value are considered as being inifinite.

If the data are accepted by the fixed part, the fixed part shall send a CTS-SPM OPERATION DATA ACCEPT to the service node and shall launch the timers Tval and Trecal related to the corresponding data, if the application time Tapplic information element is set to "apply immediately". Otherwise, the fixed part stores the new operation data and starts timer Tapplic. At Tapplic expiry, the fixed part applies the new operation data and starts the associated timers Tval and Trecal.

Similarly, the fixed part shall send CTS-SPM OPERATION DATA REJECT if the data cannot be accepted (i.e. the fixed part did not succeed in authenticating the signature issued by the service node).

4.4.4 CTS Information data request procedure

In some cases the service node may require to be informed of the data used by fixed part. The CTS Information data procedure can be initiated during any procedure started by the fixed part (e.g. enrolment procedure, operation data update procedure).

4.4.4.1 CTS Information data request

The service node initiates the CTS information data request procedure by sending a CTS-SPM INFORMATION DATA REQUEST message to the fixed part.

Upon receipt of the CTS-SPM INFORMATION DATA REQUEST message the fixed part collects the required data.

4.4.4.2 CTS Information data response

The fixed part sends a CTS-SPM INFORMATION DATA RESPONSE to the service node including these data.

4.4.5 CTS-FP de-initialisation procedure

The purpose of the CTS-FP de-initialisation procedure is to allow the CTS operator to de-initialise a given fixed part. As the fixed part has no means to address a given fixed part, this procedures follows another procedure initiated by the fixed part.

4.4.5.1 CTS-FP de-initialisation initiation

The service node initiates the CTS-FP de-initialisation procedure by sending a CTS-SPM DE-INITIALISATION REQUEST message to the fixed part and starts the timer T_deinit_SN. Upon receipt of the CTS-SPM DE-INITIALISATION REQUEST message the fixed part stops operation.

4.4.5.2 CTS de-initialisation completion

As a response to the message the fixed part sends a CTS-SPM DE-INITIALISATION COMPLETE message.

If the fixed part does not accept the de-initialisation command (i.e. the fixed part did not succeed in authenticating the signature issued by the service node) it sends a CTS-SPM DE-INITIALISATION REJECT message to the service node. Upon reception of either CTS-SPM DE-INITIALISATION COMPLETE or CTS-SPM DE-INITIALISATION REJECT, the service node stops timer T_deinit_SN.

4.4.6 CTS-SPM de-enrolment procedure

The CTS-SPM de-enrolment of a mobile from a fixed part can be initiated either by the fixed part or by the service node.

4.4.6.1 CTS-SPM de-enrolment initiated by the fixed part

If the CTS-SPM de-enrolment procedure is initiated by the fixed part, the fixed part informs the service node of the mobile de-enrolment if specified by the operator at subscription setting, by sending a CTS-SPM DE-ENROLMENT INDICATION.

If the de-enrolment is initiated by the service node, the following procedure applies.

4.4.6.2 CTS-SPM de-enrolment initiated by the service node

The service node initiates the CTS-SPM de-enrolment procedure by sending a CTS-SPM DE-ENROLMENT REQUEST command to the fixed part including the mobile identity.

Upon reception of the de-enrolment message, the fixed part performs de-enrolment of the specified mobile and responds by sending a CTS-SPM DE-ENROLMENT COMPLETE.

4.4.7 CTS FP authentication procedure

The purpose of the fixed part authentication procedure is twofold:

First to permit the network to check whether the identity provided by the fixed part is acceptable or not.

Second to provide parameters enabling the service node and the fixed part to calculate the signature key.

The cases where the authentication procedure should be used are defined in GSM 03.56.

The fixed part authentication procedure is always initiated and controlled by the CTS operator.

4.4.7.1 CTS FP authentication request

The service node initiates the CTS FP authentication procedure by sending a CTS-SPM FP AUTHENTICATION REQUEST message to the fixed part and starting timer T_FPauth_SN.

Upon receipt of the CTS-SPM FP authentication REQUEST message the fixed part calculates the response (cf. GSM 03.20 Annex E).

4.4.7.2 CTS FP authentication response

The fixed part processes a challenge response and sends it to the service node in a CTS-SPM FP AUTHENTICATION RESPONSE message. Upon reception of this message, the service node stops timer T_FPauth_SN.

If the FP authentication fails the service node replies with a CTS-SPM FP AUTHENTICATION REJECT message.

4.4.8 CTS MS authentication procedure

Mobile authentication can be performed if required by the CTS operator. The procedure is similar to the GSM authentication procedure and aims to authenticate the mobile subscriber identity (the ciphering key is not required as no encryption applies through the CTS-FP/CTS-SN interface).

The mobile authentication procedure is always initiated and controlled by the service node.

4.4.8.1 CTS MS authentication request

The service node initiates the mobile authentication procedure by sending a CTS-SPM MS AUTHENTICATION REQUEST message to the fixed part and starts timer T_MSauth_SN. The fixed part acts as a relay and sends that request message to the mobile station.

4.4.8.2 CTS MS authentication response

When the challenge response is transmitted from the mobile to the fixed part in a procedure described in GSM 04.56, the fixed part sends it to the service node in a CTS-SPM MS AUTHENTICATION RESPONSE message. The service node stops timer T_MSauth_SN.

If the authentication fails the service node replies with a CTS-SPM MS AUTHENTICATION REJECT message.