5.2.1 Basic principles

32.2503GPPCharging managementCircuit Switched (CS) domain chargingRelease 17Telecommunication managementTS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.2.1.0 Introduction

This clause contains a number of example scenarios illustrating the purpose and practical usage of the various types of records defined in the previous clauses. These examples are by no means exhaustive.

For the purpose of these examples, the following assumptions have been made:

– that the MSC server and VLR are co-located;

– that the records are sent to a post-processing system;

– that the generation of all of the record types described in this clause has been enabled;

– that the HLR interrogation records are produced in the HLR and not the interrogating MSC server;

– that supplementary service actions are recorded in separate CDRs.

The following conventions have been used for the figures contained within this clause:

1) Network connections and signalling transactions are illustrated by means of solid lines and referenced by number e.g. (1);

2) Operation & Maintenance actions, such as the transfer of CDRs, are represented by means of dotted lines and referenced by letter e.g. (A);

3) The Billing System has been included in some, but not all, of the examples. The only reason for this decision is to simplify the resulting figures. The presence of a Billing System is assumed even if not explicitly included.

The following examples are included:

1) Mobile to Land (outgoing) call;

2) Land to Mobile (incoming) call;

3) Mobile to Mobile call within the same network;

4) Incoming call to a roaming subscriber;

5) Incoming call to a PLMN Service Centre;

6) Call Forwarding Unconditional;

7) Call Forwarding conditional (on Busy);

8) Delivery of a Mobile Terminated Short Message;

9) Call Hold and Multi-party services;

10) Outgoing call handled by CAMEL;

11) Incoming call handled by CAMEL without redirection;

12) Incoming call to a roaming subscriber handled by CAMEL;

13) Incoming call handled by CAMEL with redirection decided and forwarding leg handled by CAMEL;

14) Incoming call handled by CAMEL without redirection and forwarded early using GSM SS but controlled by CAMEL;

15) Incoming call handled by CAMEL without redirection and forwarded late using GSM SS but controlled by CAMEL;

16) Early forwarded call controlled by CAMEL;

17) Late forwarded call controlled by CAMEL;

18) Incoming call handled by CAMEL with redirection initiated by CAMEL feature;

19) Incoming call handled by CAMEL in MSC Server without redirection;

20) Outgoing call handled by CAMEL Dialled CSI Trigger;

21) Incoming call handled by CAMEL with redirection decided and forwarding leg handled by CAMEL;

22) gsmSCF initiated wake-up call handled by CAMEL CPH;

23) Three party conference handled by CAMEL CPH;

24) Mobile terminated location request;

25) Mobile originating by ICS register;

26) ICS user registration via CS access.

5.2.1.1 Mobile to land (outgoing) call

Figure 5.2.1.1 illustrates a simple outgoing call from a PLMN subscriber "A" to a fixed network subscriber "B" (1).

The originating MSC server (MSC-A) shall generate an MOC record for subscriber "A".

The GMSC server shall create an outgoing gateway record for accounting with the fixed network including details of the point at which the call left the PLMN i.e. the GMSC server id. and outgoing trunk group. This record also includes time stamps to determine both the holding time of the outgoing trunk and the duration of the conversation.

Even if the MSC server and GMSC server are co-located both records shall be produced.

The records generated are subsequently transferred to the Billing System of the PLMN (A).

Figure 5.2.1.1: Mobile to land (outgoing) call

5.2.1.2 Land to mobile (incoming) call

Figure 5.2.1.2 illustrates a simple incoming call from a fixed network subscriber "A" to a PLMN subscriber "B".

The incoming call is first routed to a GMSC server (1). The GMSC server shall create an incoming gateway record for fixed network accounting purposes to record the point at which the call entered the network together with the time stamps required to calculate the holding time of the incoming trunk and the conversation duration. This gateway record shall contain the IMSI of the called subscriber.

The GMSC server interrogates the HLR of the called subscriber in order to determine his current location (2). The HLR shall create an HLR interrogation CDR.

The GMSC server routes the call to the MSC server at which the subscriber is currently registered (3). This terminating MSC server (MSC-B) shall create an MTC record for subscriber "B".

Even if the MSC server and GMSC server are co-located both the MTC and gateway records shall be produced.

The records generated are subsequently transferred to the Billing System of the PLMN (A).

Figure 5.2.1.2: Land to mobile (incoming) call

5.2.1.3 Mobile to mobile call within the same network

Figure 5.2.1.3 illustrates a simple mobile to mobile call from subscriber "A" to subscriber "B" both within the same PLMN.

The originating MSC server (MSC-A) shall produce an MOC record for the call to subscriber "B".

Having received a set-up request from subscriber "A" (1), MSC-A interrogates the HLR of the called subscriber in order to determine his current location (2). The HLR shall create an HLR interrogation CDR.

MSC-A routes the call to the MSC server at which subscriber is currently registered (3). This terminating MSC server (MSC-B) shall create an MTC record for subscriber "B". If MSC-A and MSC-B are co-located, then both the MOC and the MTC records shall be produced in the same MSC for this call.

The records generated are subsequently transferred to the Billing System of the PLMN.

Figure 5.2.1.3: Mobile to mobile call

5.2.1.4 Incoming call to a roaming subscriber

Figure 5.2.1.4 illustrates an incoming call from a fixed network subscriber "A" to a PLMN subscriber "B" who is currently roaming in another PLMN.

The call is first routed to a GMSC server (1) and the GMSC server shall create an incoming gateway record for accounting purposes as described in clause 5.2.1.2. The GMSC server interrogates the HLR of the called subscriber in order to determine his current location (2). The HLR shall create an Interrogation event record.

The GMSC server routes the call to the VPLMN in which subscriber "B" is currently located (3). The GMSC server shall create an outgoing gateway record for accounting purposes. The GMSC server shall also create a roaming record. This record includes the IMSI of the "B" subscriber and may be used as a cross-check for the TAP information received from the VPLMN.

The call is then routed by the VPLMN to the MSC server at which the subscriber is currently located (4). The GMSC server of the VPLMN shall produce an incoming gateway record and the terminating MSC server shall create an MTC record for the call to "B".

The records generated are subsequently transferred to the Billing System of the appropriate PLMN (A). The MTC record generated by the terminating MSC server shall be employed to create the appropriate MTC TAP record. The TAP records shall be included in a TAP file and transmitted to the HPLMN (B).

Figure 5.2.1.4: Incoming call to a roaming subscriber

5.2.1.5 Incoming call to a PLMN service centre

Figure 5.2.1.5 illustrates an incoming call from a fixed network subscriber "A" to a Service Centre directly connected to an MSC server within a PLMN network. Examples for services provided by such a Service Centre include Voice Mail services, Operator services, etc.

The call is routed to a GMSC server within the PLMN (1). The GMSC server analyses the dialled digits and routes the call directly to the MSC server to which the Service Centre is connected (2).

As HLR interrogation is not required, there will be no HLR Interrogation record. The GMSC server shall however, create an incoming gateway record based on the point at which the call entered the network and the destination (Service Centre) of the call.

The MSC server then connects the calling subscriber to the service centre. As no mobile subscriber is involved, the MSC server will not create an MTC record, however, the MSC server shall create a transit record describing the destination of the call.

The records generated are subsequently transferred to the Billing System of the PLMN (A).

It should be noted that without the transit record, the MSC server would not generate a record for this connection.

Figure 5.2.1.5: Incoming call to a PLMN service centre

5.2.1.6 Call forwarding unconditional

Figure 5.2.1.6 illustrates an incoming call from a fixed network subscriber "A" to a mobile subscriber "B" who has registered and activated Call Forwarding Unconditional (CFU) for the appropriate service. The call is subsequently forwarded to a second fixed network subscriber "C".

For simplicity the registration and activation of CFU have not been included in the diagram. These actions shall of course be recorded in the appropriate supplementary service records.

The incoming call is routed to a GMSC server (1). This part of the connection is identical to the scenario outlined in clause 5.2.1.2.

The GMSC server interrogates the HLR of the called subscriber in order to determine his current location (2). The HLR shall create an HLR interrogation CDR. The HLR informs the GMSC server that "B" has activated CFU to subscriber "C".

The GMSC server forwards the call to the fixed network subscriber "C" (3). The GMSC server shall create an MTC record for the "B" subscriber for the call from "A" and an MOC (call forwarding) record for the "B" subscriber for the call to "C". Both records shall contain the supplementary service employed (CFU). The GMSC server shall also produce an outgoing gateway record as described in clause 5.2.1.1.

The records generated are subsequently transferred to the Billing System of the HPLMN (A).

Figure 5.2.1.6: Call forwarding unconditional

5.2.1.7 Call forwarding conditional (on busy)

Figure 5.2.1.7 illustrates a mobile originated call from subscriber "A" to a second mobile subscriber "B" who has registered and activated Call Forwarding on Busy (CFB) for the appropriate service. The call is subsequently forwarded to a third mobile subscriber "C". In this example, all three subscribers are currently located within the same (the home) network.

For simplicity the registration and activation of CFB have not been included in the diagram.

Having received a set-up request from subscriber "A" (1), the originating MSC server (MSC-A) interrogates the HLR of subscriber "B" in order to determine his current location (1a). The call is then routed to MSC-B (2).

MSC-A shall create an MOC record for subscriber "A" containing details of the call to "B". The HLR shall produce an HLR interrogation record.

On determining that subscriber "B" is busy and that CFB is active, the forwarding MSC server/VLR (MSC-B) interrogates the HLR of subscriber "C" to determine his current location (2a) and forwards the call accordingly (3).

MSC-B shall produce an MTC record for the "B" subscriber for the call from "A" and an MOC record for the "B" subscriber for the call to "C". Both records shall include the supplementary service employed (CFB). The HLR shall produce an Interrogation record.

The terminating MSC server (MSC-C) shall create a normal MTC record for subscriber "C".

The records generated are subsequently transferred to the Billing System of the PLMN.

Figure 5.2.1.7: Call forwarding conditional (busy)

5.2.1.8 Delivery of a mobile terminated short message

Figure 5.2.1.8 illustrates the delivery of a short message to a mobile subscriber.

The short message service centre delivers the message to a GMSC server or gateway function (1). The GMSC server shall create an SMS gateway MT record.

The GMSC server then interrogates the HLR of the subscriber to determine his current location (2). The HLR shall create an HLR interrogation record.

The message is subsequently transmitted to the MSC server serving the mobile subscriber and finally to the mobile station of that subscriber (3). The MSC server shall create an SMS MT record.

The records generated are subsequently transferred to the post-processing system of the HPLMN (A).

Figure 5.2.1.8: Delivery of a short message to a mobile subscriber

5.2.1.9 Call hold and multi-party service

Figure 5.2.1.9 illustrates the use of the call hold and multi-party services.

A mobile subscriber ("A") sets up an outgoing call (1) to an ISDN subscriber ("B"). This call is recorded as outlined in clause 5.2.1.1.

Subscriber "A" then invokes the call hold service. MSC-A shall produce a supplementary service action record for the invocation.

Subscriber "A" then sets up a side-call (2) to a second mobile subscriber ("C") within the same network. This call is recorded as outlined in clause 5.2.1.3.

Subscriber "A" subsequently invokes the multi-party service in order to set up a three-party conference with "B" and "C". MSC-A shall produce a common equipment record for the use of a conference circuit by subscriber "A". This record shall record the duration of the whole conference irrespective of the number of parties subsequently added to, or removed from the conference connection.

Note that the MOC records produced by MSC-A for both the A -> B and A -> C legs of the conference shall contain the supplementary service code for multi-party.

Figure 5.2.1.9: Call hold and multi-party service

5.2.1.10 Outgoing call handled by CAMEL

Figure 5.2.1.10 illustrates an outgoing CAMEL call from a mobile CAMEL subscriber "A" to a fixed network subscriber "B" (1).

The "A" subscriber has an active O-CSI (stored in the VLR). Therefore MSC server-A requests instructions from the gsmSSF which passes the CAMEL service key to the gsmSCF to indicate which service logic it should apply (2).

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to MSC-A.

MSC server-A generates an MOC record for the "A" subscriber. This record may be linked to an optional SCF-record. The record includes O-CSI data.

The GMSC server routes the call to the "B" subscriber (3). The GMSC server shall create an outgoing gateway record as described in clause 5.2.1.1.

The generated records are subsequently transferred to the Billing System of the HPLMN (A).

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.10: Records Generated for an Outgoing Call Handled by CAMEL

GMSC server	MSC server	HLR
Outgoing gateway record	MOC record	–

Figure 5.2.1.10: Outgoing call handled by CAMEL

5.2.1.11 Incoming call handled by CAMEL without redirection

Figure 5.2.1.11 illustrates an incoming call from a fixed network subscriber "A" to a mobile CAMEL subscriber "B".

The incoming call is first routed to the GMSC server (1). The GMSC server shall create an incoming gateway record for fixed network accounting purposes.

The GMSC server interrogates the HLR of the called subscriber in order to fetch the T-CSI (2). The HLR shall create an HLR interrogation record.

The "B" subscriber has an active T-CSI. Therefore the GMSC server requests instructions from the gsmSSF which passes the CAMEL service key to a gsmSCF to indicate which service logic it should apply (3).

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to the GMSC server. The GMSC server shall generate a terminating CAMEL record which contains T-CSI data.

The GMSC server interrogates the HLR in order to determine his current location (4). The HLR shall create an HLR interrogation record.

The call is routed to MSC-B (5). An MTC record shall be generated.

For avoidance of doubt, even if the MSC server and GMSC server are co-located both the MTC and gateway records shall be produced.

The generated records are subsequently transferred to the Billing System of the HPLMN (A).

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.11: Records Generated for an Incoming Call Handled by CAMEL without Re-direction

GMSC server	MSC server	HLR
Incoming gateway record	MTC record	HLR interrogation record
Terminating CAMEL record

Figure 5.2.1.11: Incoming call handled by CAMEL without redirection

5.2.1.12 Incoming call to a roaming subscriber handled by CAMEL

Figure5.12 illustrates an incoming call from a fixed network subscriber "A" to a mobile CAMEL subscriber "B" who is currently roaming in another PLMN.

The call is first routed to a GMSC server (1) and the GMSC server shall create an incoming gateway record for fixed network accounting purposes.

The GMSC server interrogates the HLR of the called subscriber in order to fetch the T-CSI (2). The HLR shall create an HLR interrogation record.

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to the GMSC server . The GMSC server shall generate a terminating CAMEL record which contains T-CSI data.

The GMSC server interrogates the HLR in order to determine his current location (4). The HLR shall create an HLR interrogation record.

The GMSC server routes the call to the VPLMN in which subscriber "B" is currently located (5). The GMSC server shall create an outgoing gateway record for accounting purposes. The GMSC server shall also create a roaming record. This record includes the IMSI of the "B" subscriber and may be used as a cross-check for the TAP information received from the VPLMN.

The call is then routed by the VPLMN to the MSC server at which the subscriber is currently located (6). The GMSC server of the VPLMN shall produce an incoming gateway record and the terminating MSC server shall create an MTC record for the call to "B".

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.12.1: Records Generated in the HPLMN for an
Incoming Call to a Roaming Subscriber Handled by CAMEL

GMSC server	MSC server	HLR
Incoming gateway record	–	HLR interrogation record
Terminating CAMEL record
Roaming record
Outgoing gateway record

The following records are generated in VPLMN in this call scenario.

Table 5.2.1.12.2: Records Generated in the VPLMN for an
Incoming Call to a Roaming Subscriber Handled by CAMEL

GMSC server	MSC server	HLR
Incoming gateway record	MTC record	–

Figure 5.2.1.12: Incoming call to a roaming subscriber handled by CAMEL

5.2.1.13 Incoming call handled by CAMEL with redirection decided and forwarding leg handled by CAMEL

Figure 5.2.1.13 illustrates an incoming call from a fixed network subscriber "A" to a mobile CAMEL subscriber "B". The call is subsequently forwarded to a second fixed network subscriber "C" by CAMEL initiated Call Forwarding.

The incoming call is routed to the GMSC server (1). The GMSC server shall create an incoming gateway record for fixed network accounting purposes.

The GMSC server interrogates the HLR of the called subscriber in order to fetch the T-CSI and O-CSI (2).

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

The gsmSCF modifies the Called Party number and sets the CAP parameter ‘Apply O-CSI’. When gsmSCF processing is complete the call control is returned to the GMSC server. The GMSC server shall generate a terminating CAMEL record which contains T-CSI data.

The "B" subscriber has an active O-CSI. Therefore the GMSC server requests instructions from the gsmSSF which passes the CAMEL service key to a gsmSCF to indicate which service logic it should apply (4).

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to the GMSC server.

The GMSC server redirects the call to the fixed network subscriber "C" (5). The GMSC server shall generate an MTC record for the "B" subscriber for the call from "A" and an MOC (call forwarding) record for the "B" subscriber for the call to "C". The MOC record includes O-CSI data and the parameter ‘CAMEL initiated CF indicator’. The GMSC server shall also produce an outgoing gateway record as described in clause 5.2.1.1.

The generated records are subsequently transferred to the Billing System of the HPLMN (A).

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.13: Records Generated in the Incoming Call with
Redirection Decided and Forwarded Leg Handled by CAMEL

GMSC server	MSC server	HLR
Incoming gateway record	–	HLR interrogation record
Terminating CAMEL record
MTC record
MOC (CF) record
Outgoing gateway record

Figure 5.2.1.13: Incoming call handled by CAMEL with redirection decided
and forwarding leg handled by CAMEL

5.2.1.14 Incoming call handled by CAMEL without redirection and forwarded early using GSM SS but controlled by CAMEL

Figure 5.2.1.14 illustrates an incoming call from a fixed network subscriber "A" to a mobile CAMEL subscriber "B". The call is subsequently forwarded to a second fixed network subscriber "C" by GSM SS Call Forwarding Unconditional (CFU) but controlled by CAMEL.

For simplicity the activation and registration of CFU have not been included in the diagram. These actions shall of course be registered in the appropriate supplementary service records.

The incoming call is routed to the GMSC server (1). The GMSC server shall create an incoming gateway record for fixed network accounting purposes.

The GMSC server interrogates the HLR of the called subscriber in order to fetch the T-CSI and O-CSI (2). The HLR shall create an HLR interrogation record. The HLR informs the GMSC server that "B" has activated CFU.

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to the GMSC server. The GMSC server shall generate a terminating CAMEL interrogation record which contains T-CSI data.

The "B" subscriber has an active O-CSI. Because the "B" subscriber has activated CFU he acts as the originating party for the forwarded leg. Therefore the GMSC server requests instructions from the gsmSSF which passes the CAMEL service key to a gsmSCF to indicate which service logic it should apply (5).

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to the GMSC server.

The GMSC server redirects the call to the fixed network subscriber "C" (6). The GMSC server shall generate an MTC record for the "B" subscriber for the call from "A" and an MOC (call forwarding) record for the "B" subscriber for the call to "C". The MOC record includes O-CSI data. The GMSC server shall also produce an outgoing gateway record as described in clause 5.2.1.1.

If the B-subscriber do not have an active O-CSI the call is forwarded to the "C" subscriber after the first gsmSCF invocation, and the GMSC server shall generate an MOC (call forwarding) record for the "B" subscriber for the call to "C".

The generated records are subsequently transferred to the Billing System of the HPLMN (A).

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.14: Records Generated in the Incoming call handled by CAMEL without redirection
and forwarded early using GSM SS but controlled by CAMEL

GMSC server	MSC server	HLR
Incoming gateway record	–	HLR interrogation record
Terminating CAMEL record
MTC record
MOC (CF) record
Outgoing gateway record

Figure 5.2.1.14: Incoming call handled by CAMEL without redirection
and forwarded early using GSM SS but controlled by CAMEL

5.2.1.15 Incoming call handled by CAMEL without redirection and forwarded late using GSM SS but controlled by CAMEL

Figure 5.2.1.15 illustrates an incoming call from a fixed network subscriber "A" to a mobile CAMEL subscriber "B" who has registered and activated Call Forwarding on No Reply (CFNRY) for the appropriate service. The call is subsequently forwarded to a second fixed network subscriber "C".

For simplicity the registration and activation of CFNRY have not been included in this diagram. These actions shall be recorded in the appropriate supplementary service records.

The incoming call is routed to the GMSC server (1). The GMSC server shall create an incoming gateway record for fixed network accounting purposes.

The GMSC server interrogates the HLR of the called subscriber in order to fetch the T-CSI and O-CSI (2). The HLR shall create an HLR interrogation record.

The "B" subscriber has an active T-CSI. Therefore the GMSC server requests instructions from the gsmSSF which passes the CAMEL service key to the gsmSCF to indicate which service logic it should apply (3).

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to the GMSC server. The GMSC server shall generate a terminating CAMEL interrogation record which contains T-CSI data.

The GMSC server interrogates the HLR in order to determine his current location (4). The HLR shall create an HLR interrogation record.

The call is routed to MSC-B (5). The "B" subscriber do not answer the call. MSC-B shall produce an MTC record for the "B" subscriber for the call from "A".

The "B" subscriber has an active O-CSI. Because the "B" subscriber has activated CFNRY he acts as the originating party for the forwarded leg. Therefore MSC-B requests instructions from the gsmSSF which passes the CAMEL service key to the gsmSCF to indicate which service logic it should apply (6).

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to MSC-B.

MSC-B forwards the call via the GMSC server to the "C" subscriber (7). MSC-B shall produce an MOC (call forwarding) for the "B" subscriber for the call to "C". The record includes O-CSI data. The GMSC server shall also produce an outgoing gateway record as described in clause 5.2.1.1.

If the B-subscriber do not have an active O-CSI the call is forwarded to the "C" subscriber after detecting the call forwarding condition, and the GMSC server shall generate an MOC (call forwarding) record for the "B" subscriber for the call to "C".

The generated records are subsequently transferred to the Billing System of the HPLMN (A).

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.15: Records Generated in the Incoming call handled by CAMEL without redirection
and forwarded late using GSM SS but controlled by CAMEL

GMSC server	MSC server	HLR
Incoming gateway record	MTC record	–
Terminating CAMEL record	MOC (CF) record
Outgoing gateway record

Figure 5.2.1.15: Incoming call handled by CAMEL without redirection
and forwarded late using GSM SS but controlled by CAMEL

5.2.1.16 Early forwarded call controlled by CAMEL

Figure 5.2.1.16 illustrates an incoming call from a fixed network subscriber "A" to a mobile CAMEL subscriber "B". The call is subsequently forwarded to a second fixed network subscriber "C" by GSM SS Call Forwarding Unconditional (CFU) but controlled by CAMEL.

For simplicity the activation and registration of CFU have not been included in the diagram. These actions shall of course be registered in the appropriate supplementary service records.

The incoming call is routed to the GMSC server (1). The GMSC server shall create an incoming gateway record for fixed network accounting purposes.

The GMSC server interrogates the HLR of the called subscriber in order to fetch the O-CSI (2). The HLR shall create an HLR interrogation record. The HLR informs the GMSC server that "B" has activated CFU.

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to the GMSC server.

The GMSC server redirects the call to the fixed network subscriber "C" (5). The GMSC server shall generate an MTC record for the "B" subscriber for the call from "A" and an MOC (call forwarding) record for the "B" subscriber for the call to "C". The MOC record includes O-CSI data. The GMSC server shall also produce an outgoing gateway record as described in clause 5.2.1.1.

The generated records are subsequently transferred to the Billing System of the HPLMN (A).

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.16: Records Generated in the Early forwarded call controlled by CAMEL

GMSC server	MSC server	HLR
Incoming gateway record	–	HLR interrogation record
MTC record
MOC (CF) record
Outgoing gateway record

Figure 5.2.1.16: Early forwarded call controlled by CAMEL

5.2.1.17 Late forwarded call controlled by CAMEL

Figure 5.2.1.17 illustrates an incoming call from a fixed network subscriber "A" to a mobile CAMEL subscriber "B" who has registered and activated Call Forwarding on No Reply (CFNRY) for the appropriate service. The call is subsequently forwarded to a second fixed network subscriber "C".

For simplicity the registration and activation of CFNRY have not been included in this diagram. These actions shall be recorded in the appropriate supplementary service records.

The incoming call is routed to the GMSC server (1). The GMSC server shall create an incoming gateway record for fixed network accounting purposes.

The GMSC server interrogates the HLR of the called subscriber in order to determine the current location (2). The HLR shall create an HLR interrogation record.

The call is routed to MSC-B (3). The "B" subscriber do not answer the call. MSC-B shall produce an MTC record for the "B" subscriber for the call from "A".

The "B" subscriber has an active O-CSI. Because the "B" subscriber has activated CFNRY he acts as the originating party for the forwarded leg. Therefore MSC-B requests instructions from the gsmSSF which passes the CAMEL service key to gsmSCF-B to indicate which service logic it should apply (4).

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to MSC-B.

MSC-B forwards the call via the GMSC server to the "C" subscriber (5). MSC-B shall produce an MOC (call forwarding) for the "B" subscriber for the call to "C". The record includes O-CSI data. The GMSC server shall also produce an outgoing gateway record as described in clause 5.2.1.1.

The generated records are subsequently transferred to the Billing System of the HPLMN (A).

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.17: Records Generated in the Late forwarded call controlled by CAMEL

GMSC server	MSC server	HLR
Incoming gateway record	MTC record	HLR interrogation record
Outgoing gateway record	MOC (CF) record

Figure 5.2.1.17: Late forwarded call controlled by CAMEL

5.2.1.18 Incoming call handled by CAMEL with redirection initiated by CAMEL feature

Figure 5.2.1.18 illustrates an incoming call from a fixed network subscriber "A" to a mobile CAMEL subscriber "B". The call is subsequently redirected to a second fixed network subscriber "C" by CAMEL initiated redirection.

The incoming call is routed to the GMSC server (1). The GMSC server shall create an incoming gateway record for fixed network accounting purposes.

The GMSC server interrogates the HLR of the called subscriber in order to fetch the T-CSI (2) and the O-CSI (2). The HLR shall create an HLR interrogation record.

Since subscriber "B" has an active T-CSI and the trigger criteria are met the GMSC server requests instructions from the gsmSSF which passes the CAMEL service key to a gsmSCF to indicate which service logic it should apply (3). A terminating CAMEL interrogation record is generated in the GMSC server for invoking the terminating CAMEL call handling.

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

The gsmSCF returns a modified destination routing address to the GMSC server (without the option "apply O-CSI"). Therefore for the redirection leg (B-C) the CAMEL feature is not invoked.

The GMSC server redirects the call to the fixed network subscriber "C" (4). For fixed network accounting purposes the GMSC server shall generate an outgoing gateway record as described in clause 5.2.1.1.

The generated records are subsequently transferred to the Billing System of the HPLMN (A).

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.18: Records Generated in the Incoming call handled by CAMEL
with redirection initiated by CAMEL feature

GMSC server	MSC server	HLR
Incoming gateway record		HLR interrogation record
Terminating CAMEL interrogation record
Outgoing gateway record

Figure 5.2.1.18: Incoming call handled by CAMEL with redirection initiated and by CAMEL feature

5.2.1.19 CAMEL Scenario for Visiting Terminator Trigger Calls

Figure 5.2.1.19 illustrates an incoming call from a fixed network subscriber "A" to a mobile CAMEL subscriber "B".

The incoming call is first routed to the GMSC (1). The GMSC shall create an incoming gateway record for fixed network accounting purposes.

The GMSC interrogates the HLR (2) of the called subscriber. The HLR shall create an HLR interrogation record. The call is routed to MSC-B(3). An MTC record shall be generated in MSC-B.

The "B" subscriber has an active VT-CSI (stored in the VLR). For avoidance of doubt in this scenario, the "B" subscriber does not have an active T-CSI in the HLR. Therefore MSC-B requests instructions from the gsmSSF which passes the CAMEL service key to the gsmSCF to indicate which service logic it should apply (4).

The gsmSCF may interrogate the HLR for subscriber information. As a network option, the operator may refuse to provide the requested information.

When gsmSCF processing is complete the call control is returned to the MSC-B. The MSC-B shall generate a terminating CAMEL (TCR) record which contains VT-CSI data.

The MSC-B routes the call to the "B" subscriber (5).

For avoidance of doubt, even if the MSC and GMSC are co-located both the MTC/TCR and gateway records shall be produced.

The generated records are subsequently transferred to the OS (A) either as event reports following the release of the connection or when collected by the OS.

The following records are generated in HPLMN in this call scenario.

Table 5.2.1.19: Records Generated for Visiting Terminating Trigger Calls

GMSC	MSC-B	HLR
Incoming gateway record	MTC record	HLR interrogation record
	Terminating CAMEL record