5.1 Activation

03.333G security3GPPLawful InterceptionStage 2TS

The following pictures show the information flow for the activation of the Lawful interception.

5.1.1 X1_1-interface

The message sent from the ADMF to the MSC/VLR and GMSC respectively (X1_1-interface) contains the:

– identity of the target (MSISDN, IMSI or IMEI) (see note 4);

– information whether the intercept product shall be provided (see note 1);

– information whether the intercept related information shall be provided (see note 1);

– address of Delivery Function 2 (DF2) for the intercept related information (see note 2);

– address of Delivery Function 3 (DF3) for the circuit switched intercept product (see note 3);

– IA in case of location dependent interception.

NOTE 1: As an option, the filtering whether intercept product and/or intercept related information has to be provided can be part of the delivery functions. If the option is used, the corresponding information can be omitted on the X1_1-interface, while "information not present" means "intercept product and related information has to be provided" for the MSC. Furthermore the delivery function which is not requested has to be "pseudo-activated", in order to prevent error cases at invocation.

NOTE 2: As an option, only a single DF2 is used by and known to every MSC in the network. In this case the address of DF2 can be omitted.

NOTE 3: As an option, only a single DF3 is used by and known to every MSC in the network. In this case the address of DF3 can be omitted.

NOTE 4: Interception of IMEI is not applicable at the GMSC.

If after activation subsequently Intercept Product (IP) or Intercept Related Information (IRI) has to be activated (or deactivated) an "activation change request" with the same identity of the target is to be sent.

Figure 3: Information flow on X1_1-interface for Lawful Interception activation

Interception of a target can be activated on request from different LEAs and each LEA may request interception via a different identity. In this case, each identity of the target on which to intercept will need to be sent via separate activation message from ADMF to MSC/VLR and GMSC on the X1_1-interface. Each activation can be for IP only, IRI only, or both IP and IRI.

When several LEAs request activation on the same identity then the ADMF determines that there are existing activations on the identity. In this case, the ADMF will not send an additional activation message to the MSC/VLR and GMSC except when the activation needs to change from IP only or IRI only to IP and IRI. In that case an activation change message will be sent to the MSC/VLR and GMSC.

5.1.2 X1_2-interface (IRI)

For the delivery of IRI the message sent from the ADMF to the Delivery Function contains:

– the identity of the target;

– the address for delivery of IRI (= LEA address);

– which subset of information shall be delivered;

– a DF2 activation identity, which uniquely identifies the activation for DF2 and is used for further interrogation or deactivation, respectively;

– the IA in case of location dependent interception;

– the warrant reference number if required by national option.

If a target is intercepted by several LEAs and/or several identities simultaneously, a single activation of delivery is necessary for each combination of LEA and identity.

Figure 4: Information flow on X1_2-interface for Lawful Interception activation

5.1.3 X1_3-interface (IP)

For the delivery of circuit switched intercept product the message sent from the ADMF to the Delivery Function contains:

– the identity of the target;

– the address of delivery for IP (= LEA address);

– a DF3 activation identity, which uniquely identifies the activation for delivery function 3 and is used for further interrogation or deactivation, respectively;

– the IA in case of location dependent interception;

– the warrant reference number if required by national option.

If a target is intercepted by several LEAs and/or several identities simultaneously, a single activation of delivery is necessary for each combination of LEA and identity.

Figure 5: Information flow on X1_3-interface for Lawful Interception activation