Camel Phase 3

Requirement Specifications for interoperability between GSM SSF and SCF

1 Scope

The scope of this document is to provide the RCOM requirement for CAMEL control relationship between SSF and SCF.2 Introduction

ETSI has started in1994 with the specification of Intelligent Network functionality in GSM, named Customized Applications for Mobile Enhanced Logic (CAMEL) .CAMEL will provide the service provider with the ability to offer operator specific services such as prepaid roaming services, fraud control, special numbers and closed user groups based on IN service logic to a subscriber even when roaming outside the HPLMN. It is a network feature and not a supplementary service. CAMEL makes use of IN SSF SCF interface via CAP (CAMEL application part).

This document addresses the details of the messages that flow under different call scenarios, between various functional entities for supporting CAMEL.3 Details3.1 Applicability of CAMEL procedures

The CAMEL feature is applicable to Mobile Originated and Mobile Terminated Call Related Activities. The CAMEL feature is applicable to Supplementary Services Invocation CAMEL procedures are applicable to GPRS sessions and PDP contexts CAMEL procedures are applicable to Mobile Originating/Terminating short message service through both circuit switched and packet switched serving network entities CAMEL procedures are applicable to IP multimedia services (except Emergency calls) to support legacy services CAMEL shall support IPMM sessions which are based on the same charging paradigm as CS/PS calls. This applies most probably to VoIP and Video over IP. CAMEL procedures are applicable to IP multimedia sessions addressed by either E.164 numbers or SIP URLs.

3.2 FUNCTIONAL ENTITIES USED FOR CAMEL PHASE 3HOME NETWORK

1.1 HLR (Home Location Register)

1.2 GSM SCF (Service control Function)

INTERROGATING NETWORK

2.1 GMSC (Gateway MSC)

2.2 GSM SSF (Service Switching Function)

VISITING NETWORK

3.1 VMSC (Mobile switching network)

3.2 GSM SSF (Service Switching Function)

3.3 VLR (Visitor Location Register)

3.4 GSM SRF (GSM Specialized Resource Function)

Fig: Functional Architecture for support of CAMEL Phase 2/3

3.2.1 Home Network

Home network presents the home PLMN of the CAMEL subscriber. Home Location Register and GSM Service Control Function are the network elements or functional entities, which are involved in CAMEL.

Home Location Register (HLR)

HLR stores two kinds of information, namely

The subscription information such as O-CSI,T-CSI,VT-CSI etc (described in section 4.4 )

Some location information enabling the charging and routing of calls towards the MSC where the MS is located.

Two types of number are attached to each mobile subscription and are stored in the HLR, namely

- the international mobile station identity (IMSI)

- Mobile station International ISDN number (MSISDN)

All the subscribers that subscribe to originating or terminating services provided by the CAMEL are marked in the HLR by having the CAMEL subscription information stored against them. The O-CSI is sent to the VLR in case of location update. The O/T-CSI is sent to GMSC in the response to a request for routing information.GSM Service Control Function

GSM- SCF acts as an entity, where the execution of operator specific services takes place. GSM SCF contains the service logic of OSSs, which is invoked during originating and terminating CAMEL calls. It interfaces with the GSMSSF and the HLR.

3.2.2 Visiting Network

The PLMN where the CAMEL subscriber is roaming is called visiting network. It is involved in the handling of originating and forwarded CAMEL calls. Moreover, visiting network may be requested for location information and a status of the subscriber.

Visitor Location Register (VLR)

VLR stores the subscriber data received from the HLR of home network. The subscriber data includes the O-CSI, VT-CSI and TIF-CSI as a part of the subscriber data for subscriber roaming in the VLR area. VLR may also be requested for subscribers location and status information at any time by HLR.

MSCThe purpose of MSC is to setup the calls from and towards the visiting subscriber. While handling the originating calls the MSC detects whether the subscriber needs CAMEL service (i.e. the subscriber has O-CSI information active). If the O-CSI exists for the subscriber, an initial contact to the GSMSCF takes place. During the CAMEL call the MSC may be requested to monitor and report certain call events by the GSMSCF.

GSM Service Switching Function

A functional entity that interfaces the MSC/GMSC containing the call control function to GSM-SCF containing the service control function.

3.2.3 Interrogating Network

Interrogating network performs the interrogation of the home network for information on the treatment of terminating CAMEL calls. Thus the calling party of the terminating CAMEL call resides in the interrogating network and the called party resides in the visiting network. GMSC and GSM-SSF are the entities, which are related to the handling of the terminating CAMEL calls.

Gateway MSC

GMSC will interrogate the appropriate HLR and then route the call to the MSC where the mobile station is located.

When processing the calls for subscribers requiring the CAMEL support the GMSC receives a O/T CSI from the HLR, indicating the GMSC to request instructions from the GSM-SSF. The GMSC monitors on request the call states (events) and informs the GSM-SSF of these states during processing enabling the GSM-SSF to control the execution of the call in the GMSC.

GSM-SRF (GSM Specialized Resource Function):

The specialized resource functions provide a pool of resources for access by other network entities. The resources include for example sending of announcements to the parties in a call, speech reorganization, and specialized connection resources (e.g. audio conference bridge) etc. NOTE: Mobile Application Part (MAP) messages sent between mobile switches and databases to support user authentication, equipment identification, and roaming are carried by TCAP In mobile networks (IS-41 and GSM) when a mobile subscriber roams into a new mobile switching center (MSC) area, the integrated visitor location register requests service profile information from the subscriber's home location register (HLR) using MAP (mobile application part) information carried within TCAP messages. All the IN messages are carried out by the application of CAP (CAMEL Application part)

3.3 Interfaces defined for CAMEL

This sub clause describes the different interfaces applicable to CAMEL.

3.3.1 HLR - VLR interface

This interface is used to send the CAMEL related subscriber data to the visited PLMN and for provision of MSRN. The interface is also used to retrieve subscriber status and location information of the mobile subscriber or to indicate suppression of announcement for a CAMEL service.

3.3.2 GMSC - HLR interface

This interface is used at terminating calls to exchange routing information, subscriber status, location information, subscription information and suppression of announcements. The O/T-CSI that is passed to the IPLMN is sent over this interface.

3.3.3 GMSC GSM-SSF interface

This is an internal interface. The interface is described in the specification to make it easier to understand the handling of DPs (arming/disarming of DPs, DP processing etc.).

3.3.4 GSM-SSF GSM-SCF interface

This interface is used by the GSM-SCF to control a call in a certain GSM-SSF and to request the GSM-SSF to establish a connection with a GSM-SRF. Relationships on this interface are opened as a result of the GSM-SSF sending a request for instructions to the GSM-SCF.

3.3.5 MSC GSM-SSF interface

This is an internal interface. The interface is described in the specification to make it easier to understand the handling of DPs (arming/disarming of DPs, DP processing etc.).

3.3.6 GSM-SCF HLR interface

This interface is used by the GSM-SCF to request information from the HLR. As a network operator option the HLR may refuse to provide the information requested by the GSM-SCF.

3.3.7 GSM-SCF GSM-SRF interface

This interface is used by the GSM-SCF to instruct the GSM-SRF to play tones/announcements to the users.

3.3.8 GMSC - MSC interface

This interface is used to transfer control of a call from a VMSC back to a GMSC for optimal routeing.3.4 Description of CAMEL Subscriber Data

This sub clause defines the contents of the Originating CAMEL Subscription Information.

3.4.1 TDP List

The TDP List indicates on which detection point triggering shall take place.

3.4.2 GSM-SCF address

The address to be used to access the GSM-SCF for a particular subscriber; The address shall be an E.164 number, NP=1 to be used for routing. Different GSM-SCF addresses may be associated to different TDPs.

3.4.3 Service Key

The Service Key identifies to the GSM-SCF the service logic. Different Service Keys may be associated to different TDPs.

3.4.4 Default Call Handling

The Default Call Handling indicates whether the call shall be released or continued as requested in case of error in the GSM-SSF to GSM-SCF dialogue or in case the call is submitted to call gapping in the GSM-SSF. A default call handling shall be associated to each Service Key.

3.4.5 DP criteria

The DP criteria indicate whether the GSM-SSF shall request the GSM-SCF for instructions.

3.4.6 CAMEL Capability Handling

CAMEL Capability Handling indicates the phase of CAMEL which is asked by the GSM-SCF for the service. The HLR shall not include in a CSI which it sends to a VLR or GMSC any data for a CAMEL phase later than that which the CAMEL capability handling indicates. E.g. if the CAMEL Capability Handling indicates CAMEL phase 1 then the HLR shall not send triggering criteria to the VLR. Different CSIs may contain different values of CAMEL Capability Handling.

NOTE: If CAMEL is not supported or if a lower phase of CAMEL is supported in the VLR, the HLR can decide on a subscriber basis to apply ODB, perform normal call handling or perform operator specific handling (eventually support of a lower version of CSI).

3.4.7 CSI state

The CSI state indicates whether the CSI is active or not.

3.4.8 Notification flag

The notification flag indicates whether the change of the CSI shall trigger Notification on Change of Subscriber Data.3.5 Detection points

Definition and description

Certain basic call events may be visible to the GSM Service Control Function (GSM-SCF). The DPs are the points in call at which these events are detected. The DPs for Mobile Originated Calls and Mobile Terminated Calls are described in following subclasses.

A DP can be armed in order to notify the GSM-SCF that the DP was encountered, and potentially to allow the GSM-SCF to influence subsequent handling of the call. If the DP is not armed, the processing entity continues the processing without GSM-SCF involvement.

Three different types of DPs are identified:

3.5.1. Trigger Detection Point - Request (TDP-R).

This detection point is statically armed and initiates a CAMEL control relationship when encountered and there is no existing relationship due to same CSI. Processing is suspended when the DP is encountered.

3. 5.2 Event Detection Point - Request (EDP-R).

This detection point is dynamically armed within the context of a CAMEL control relationship. Processing is suspended when encountering the DP and the GSM-SSF waits for instructions from the GSM-SCF.

3.5.3 Event Detection Point - Notification (EDP-N)This detection point is dynamically armed within the context of a CAMEL control relationship. Processing is not suspended when encountering the EDP-N.3.6 Various call scenarios3.6.1 Registration process Originating Call

CAMEL based OPPS (Originating Prepaid Service) is invoked by the setting of a static trigger in the GSM-SSF when the subscriber registers. Specifically, it is expected that the HLR will return to the VLR the standard O-CSI (Originating CAMEL Service Information) as part of the registration process

Terminating CallCAMEL based TPPS (Terminating Prepaid Service) is invoked by the setting of a static trigger in the GSMSSF when the subscriber registers. Specifically, it is expected that the HLR will return to the GMSC the standard T-CSI (Terminating CAMEL Service Information) as part of the registration process.

3.6.2 Originating call scenarios

Originating PPS successful (i.e. answered) Call Setup (No Pre-Call Announcement)

In this scenario, the calling subscriber has a sufficient balance and is in valid state. So, call proceeds without the interaction of SRF/IVR. The SCF interacts with the SSF to get the notification of answer and disconnect conditions in order to charge for the call. Further charging can be done in two ways, namely Early Apply Charging( default method ,where the Apply Charging message is sent after the RRBE message i.e. ) and the second is Late Apply Charging ( where the Apply Charging Message is sent after the Answer Trigger is received )Signalling FlowMessage parameters

1. Initial DP (this message contains service key (that shows subscriber has prepaid services) , calling party number (MSISDN) ,Event type BCSM (collected info DP), called partys number, location information, call reference no (VMSC address) ,MSC address)

2. RRBE (Request report BCSM event)- This indicates the triggers that need to be monitor in the MSC and to be notified to the SCF such as O_answer, O_disconnect, O_busy,O_abandon, O_select route failure, O_no answer).3. Apply Charging this message contains max call duration, release if duration exceeds party to charge.

4. Continue message it instructs SSF to continue the call processing after notifying the triggers that has been encountered to SCF, without waiting for further instructions from SCF.

5. Activity Test this message is sent periodically to the check if the connection is active.6. ERB (Event Report BCSM event) this messages notifies the triggers encountered in the SSF like O_answer, to the SCF.

7. Charging Report this message is in response to the Apply charge message

The pictorial representation of message flow is depicted below.

ExplanationAs a call origination occurs in the MSC/SSF, A TDP R (trigger detection point -request) is set for the prepaid subscriber at the collected _info PIC (point in call) as shown in BCSM (section 4.5.1). so, as the trigger is fired , the MSC/SSF initiates a dialogue with the SCF by sending a message , Initial DP with O-CSI (CAMEL subscription information ,described in section 4.4),

In response to the InitialDP message, the SCF first analyzes the calling party number to determine the subscribers account. If the account is valid, it then performs further analysis to determine if the subscriber is allowed to make calls, is authorized to call the destination address, and if the subscribers balance is sufficient to permit the call.When the call is authorized and there is no need to play a any pre-call warning announcement, the SCF sends the RequestReportBCSM Event , ApplyCharging and Continue message to the SSP. The RequestReportBCSMEvent arms triggers that need to be monitored in the MSC/SSF. The SCF sends an Apply Charging message with the maxCallDuration and releaseIfduration Exceeded parameters set to instruct the MSC to release the call when the maximum call duration is reached and to play a warning tone prior to release. The continue message instructs the MSC/SSF to continue with the call processing until the called party answers the call and only notifying the triggers that has been encountered , without waiting for the instructions from SCF.When the call is answered, the O _Answer DP is triggered in the SSF and a notification message is sent to the SCF (ERB, EventReportBCSM message). At this point, the SCF begins charging for the call and starts the maximum call length timer based on the subscribers balance and the tariff for the call. Also, the ActivityTest message is sent periodically throughout the life of the call.to check if the connection is alive.Similarly, when either party disconnects the call , the O_disconnect DP is triggered in the SSF and is notified to the SCF. Also, the SSF sends a charging report message to the SCF in response to the Apply charge message.Originating PPS Call Set-up (Pre-Call Announcement)

In this scenario, the subscriber initiates a call when he has a low balance or when his account in near to changing state. In order to warn the subscriber of this condition, the SCP first requests the SSP to connect the subscriber to an IP/SRF so that a warning announcement can be played.

Signalling Process Flow Message parameters

1. Initial DP (this contains the parameters related to the CAMEL subscription data i.e. O_CSI, described in section 4.4)2. RRBE (Request report BCSM event)- This indicates the triggers that need to be monitor in the MSC and to be notified to the i.e. O_abandon and O_disconnect.3. Connect to resource (this shows the resource address (physical address of SRF); service interaction indicator (shows the type of communication i.e. one way or two way).

4. Play an announcement -Information to Send (announcement tone), Disconnect from IP Forbidden, (whether to disconnect after the has been announcement played), Request Announcement Complete (acknowledgement is required or not)5. IAM- initial address message

6. ACM- address complete message

7. ANM answer message.

8. Specialized resource report acknowledgement in response to play announcement message.

9. Disconnect forward connection - to disconnect a connection with a GSM-SRF previously established with a Connect to Resource IF10. RRBE (Request report BCSM event) - This indicates the triggers that need to be monitor in the MSC and to be notified to the i.e. O_answer and O_disconnect.11Apply Charging this message contains max call duration, release if duration exceeds, party to charge.

12. Continue message it instructs SSF to continue the call processing after notifying the triggers that has been encountered to SCF, without waiting for further instructions from SCF.

13 Activity Test this message is sent periodically to the check if the connection is active.

14. ERB (Event Report BCSM event) this messages notifies the triggers encountered in the SSF like O_answer, to the SCF.

15Charging Report this message is in response to the Apply charge message.The pictorial representation of message flow is depicted below.

ExplanationAS a call origination occurs in the MSC/SSF, A TDP R (trigger detection point -request) is set for the prepaid subscriber at the collected _info PIC (point in call) as shown in BCSM (section 4.5.1). so, as the trigger is fired , the MSC/SSF initiates a dialogue with the SCF by sending a message , Initial DP with O-CSI (CAMEL subscription information ,described in section 4.4),

In response to the InitialDP message, the SCF first analyzes the calling party number to determine the subscribers account. If the account is valid, it then performs further analysis to determine if the subscriber is allowed to make calls, is authorized to call the destination address, and if the subscribers balance is sufficient to permit the call.When the call is authorized however the subscribers balance is below the threshold at which a pre-call warning announcement is played, the SCF sends a RequestReportBCSMEvent message and a ConnectToResource iinstructing the SSF to get connected with an IP/SRF (Intelligent pheripheral /Specialized resource function ). The RequestReportBCSMEvent message sets a trigger to detect if the subscriber abandons the call during the warning announcement. The ConnectToResource message directs the SSP to connect the subscriber via a voice circuit to the IP.Once the voice path is established, the IP SRF executes the PlayAnnouncement concatenated to the ConnectToResource message. The connect to resource message provides the address of the intelligent pheripheral with which the connection needs to be established .After playing the announcement , a specialized resource message is sent back to the SCF , in response to which ,it instructs the SSF to disconnect the connection with the SRF.Also, RRBE message is again sent to the SSF to monitor the triggers like O_answer and O_disconnect , along with continue and apply charge message. The apply charge message indicates the max call duration allowed and what needs to be done if the call limit exceeds.

Originating call and calling party abandons the call.

This scenario deals with calls that are terminated by the subscriber before the called party answers. This can be because the calling subscriber abandons during alerting, the called party is busy or the terminating switch determines that there is no answer.Signalling flow


Explanation In this is scenario, when a call has not yet reached the active state and either the subscriber disconnects or a busy or no answer condition is detected, one of the triggers that were armed during call setup is reached for example as soon as O_abandon DP is triggered in the SSF, the SSF sends an Eventreport BCSM indicating the call termination due to interruption. Also the Apply charging report message with the Callactive parameter set to false is sent to the SCF. If in this message, the parameter miscallinfo indicates the trigger was armed as interrupted, the SCF sends a release message to the SSF) in order to stop.

Originating Call not allowed as customer has low balance

Explanation:

In case, subscriber does not have the sufficient balance to originate a call, the SCP will instruct the SRF to play an announcement of the low balance to the subscriber and then instructs the MSC to release the connection.Signalling Flow:The pictorial representation of message flow is depicted below.

3.6.3 Terminating prepaid call In this scenario, a call to the subscriber (who is roaming) is made when his account has sufficient balance and is in a valid state. The SCP interacts with the MSC to be notified of answer and disconnect conditions in order to charge for the call.

Message Parameters

1. IAM initial address message

2. SRI send routing information (this contains the MSISDN number of the called party)

3. SRI ACK send routing information acknowledgement (this message contains the T-CSI (terminating party CAMEL subscription information as described in section 4.4)

4. Initial DP ( this message contains the service key ,called party and calling party number , location information ,redirection information, calling partys category etc)

5. RRBE (request report BCSM event) (describes the triggers that SSF needs to monitor and notify like T answer, T_disconnect, T_abandon ,T_busy, T_no answer))

6. Apply charging (this message max call period duration, release if duration exceeds and party to charge.)

7. continue (this message contains no parameters however it instructs the SSP to collect charging information as well continue with processing after the notification of trigger encountered ,without waiting for further instructions )

8. T- suppress (this message contains the terminating party CAMEL subscription information sent back to the HLR)

9. PRN (provide routing information) (this specify the roaming number of the called party)

10. MSRN ( this the acknowledgement message in response to PRN)

11. ACM( Address complete message )

12. ANM (Answer message )

13. ERB ( Event Report BCSM , specify the trigger that has been encountered such as T_answer)

14. Charging report (this is in reponse to apply charging)

Signalling flow


Explanation As call origination and dialed digits are received by the GMSC, it interrogates the HLR to get the current location of the called party, by sending a request message (send routing information (SRI)) containing MSISDN number for the called party. In response to this the HLR sends back SRI ACK (send routing information acknowledgement) message containing terminating partys subscription information (T-CSI, described in section 4.4 ).

The GMSC sends this T-CSI to the SCF( service control function) in the initial DP message indicating that a TDP-R( trigger detection point request ) has been set for the prepaid subscriber at the terminating attempt _authorized PIC (point in call) as shown in the BCSM (Basic call state model ,section 4.5.2).

When the SCF receives the InitialDP message, it first analyzes the called party number to determine the subscribers account. If the account is valid, it then performs further analysis to determine if the subscriber is allowed to make calls, is authorized to call the destination address, and if the subscribers balance is sufficient to permit the call.

When the call is authorized, the SCF sends the RequestReportBCSMEvent, ApplyCharging and Continue message to the SSF. The RequestReportBCSMEvent arms triggers for when the call is answered or terminated. It specifics the triggers that GMSC needs to monitor and notify. The SCF sends an Apply Charging message with the maxCallPeriodDuration and releaseIfduration Exceeded parameters set to instruct the MSC to release the call when the maximum call duration is reached and to play a warning tone prior to release. Also, the continue message instructs the GMSC to continue with the processing without waiting for further instructions from SCF.

The GMSC sends T-CSI suppress message to the HLR and requests to send the roaming number for the called party. In the response to which, the HLR refers to VLR by sending a request to provided the roaming number via PRN message. The VLR sends back the MSRN (mobile subscriber roaming number) to the HLR, which is further sent to GMSC.

After receiving the MSRN number which specifies the serving MSC for the called party, the GMSC sends the called and calling partys numbers in the IAM (initial address message). In response to which the serving VMSC (visited MSC) sends a ACM (address complete message).

When the call is answered, the T_Answer DP is triggered in the GMSC/SSF and an EventReportBCSM message is sent to the SCF. At this point, the GMSC/SSF begins charging for the call and starts the maximum call length timer based on the subscribers balance and the tariff for the call. The ActivityTest message continues to be sent periodically throughout the life of the call and when either party calling or called party disconnects the call the T_disconnect is triggered in the GMSC/SSF and the report is sent to the SCF along with the charging report.

Terminating PPS call not allowed

This scenario covers the situation when the call party is not in a state to receive a call may be subscriber is roaming and does not have the sufficient balance. In the case the SCP directs the SSP to connect the calling party to an external IP/SRF in order to play a subscriber unavailable announcement.

Signalling Flow


Explanation:

The GMSC/SSF sends the T-CSI to the SCF( service control function) in the initial DP message indicating that a TDP-R( trigger detection point request ) has been set for the prepaid subscriber at the terminating attempt _authorized PIC (point in call) as shown in the BCSM (Basic call state model ,section 4.5.2).


If any of the authorization checks fail, the SCP sends a RequestReportBCSMEvent message and an EstablishTemporaryConnection message to the SSP. The RequestReportBCSMEvent message sets a trigger to detect if the calling party abandons the call. The EstablishTemporaryConnection message provides Assisting SSP IP Routing Address and directs the SSP to connect to an IP. The SCF also sends a continue message to the SSF instructing to continue with call processing.After the connection to the IP is made, the SCF directs the IP to play an announcement to the caller. Also, the SCF activates a guard timer, T scf-ssf. If this timer expires, the SCP sends a ResetTimer message to the SSP to cause it to reinitialize its TSSF timer and this will be repeated each TSCF-SSF until the temporary connection is released.

After the announcement has finished playing, the IP function notifies the SCP function that the announcement has been played. The SCP then sends a DisconnectForwardConnection message to disconnect the IP connection and a ReleaseCall message to the SSP. When the ReleaseCall message is received, the SSP terminates the call.3.6.4 Network Initiated Call Termination (Maximum Call Duration Exceeded)

This scenario covers the situation in which the Network terminates a call because the call has exceeded the maximum call lengthSignaling Flow:


Explanation:

After a call has reached the active state, the Activity Test procedure, continues until the maximum call length has reached. .i.e. the SCF periodically sends a activity Test Message to the SSF untill the maximum call length, indicated by the ApplyCharging messages has reached. There after the SCF directs the SSP/MSC to play a warning tone to the subscriber before releasing the call. So, when the maximum call duration is reached the SSP disconnects the call and sends an ApplyChargingReport message to the SCP.The ApplyChargingReport message terminates SCP processing.

3.6.5 SCP-Initiated Call Termination (Maximum Call Duration, Balance Exhausted)

This scenario covers the situation in which the network does not terminate a call as instructed in the ApplyCharging message in a timely fashion. In this case, as a save guard, the call is terminated by the SCP because the subscribers balance has reached the minimum allowed or because it has exceeded the maximum call length.

Signalling Flow:


Explanation:After a call has reached the active state, the Activity Test procedure, continues until the maximum call length has reached. .i.e. the SCF periodically sends a activity Test Message to the SSF untill the maximum call length, indicated by the ApplyCharging messages has reached. Once the balance is exhausted or maximum call length has reached .the SCF directs the SSF to disconnect the call by sending a ReleaseCall message. When the ReleaseCall message is received, the SSP then terminates the call.

3.6.6 Call forwarding scenarios

This sub clause describes the following two scenarios

4.6.4.1 Early Call Forwarding (unconditional Call forwarding)

4.6.4.2 Late Call Forwarding (conditional call forwarding)

Early Call forwarding (unconditional Call forwarding)

In this scenario, the B-Party has manually forwarded his number to another number say c-party. So, In this scenario, the subscriber (B-party) has CF Unconditional enabled and receives a call.

Signalling Flow The pictorial representation of message flow is depicted below.

Explanation:

In the GMSC it is determined that Unconditional CF is enabled. The GMSC creates a new call leg to a C-party.

The GMSC sends this T-CSI to the SCF (service control function) in the initial DP message indicating that a TDP-R (trigger detection point request) has been set for the prepaid subscriber at the terminating_attempt _authorized PIC (point in call) as shown in the BCSM (Basic call state model, section 4.5.2).

When the SCF receives the InitialDP message, it first analyzes the type of call. If the GSM-ForwardingPending parameter is present, the call will be subject to GSM Call Forwarding if the PPS account status allows it. PPS uses the B-Number (Subscriber ID) to determine the status of the PPS account.

If the account is valid, the SCF sends a RequestReportBCSMEvent and Continue message to the SSF. The RequestReportBCSMEvent arms triggers to allow the SCF to remain in control of the T(A-B) relationship.

As the PPS subscriber is also an Originating subscriber, the MSC creates a new O(B-C) relationship for the forwarded call. A TDP-R is set for the prepaid subscriber at the collected_info PIC (DP2). When the forwarded call is executed, the trigger fires and the SSF will send an InitialDP message to the SCF.

When the SCF receives the InitialDP message, it first analyzes the type of call. If the Redirection Information parameter is present, it is a forwarded call. If a Redirecting Party ID is present the SCF uses this information to determine the status of the PPS account. If the account is valid, further analysis takes place.

If the Forwarding Party (PPS subscriber) is authorized to call the destination address, and if the subscribers balance is sufficient to permit the call, the SCF sends the RequestReportBCSMEvent and Continue and message to the SSP. If the forwarded call is chargeable, the SCF also sends an ApplyCharging message with the maxCallPeriodDuration and releaseIfdurationExceeded parameters. The RequestReportBCSMEvent arms triggers for when the call is answered or terminated.

The SSF then continues with normal call establishment until the called party answers the call. The SCF begins an ActivityTest timer (TActTest), whose expiration causes an ActivityTest message to be periodically sent to the SSF. This is used to ensure that the dialog is still active at the SSF.

When the forwarded call is answered, the oAnswer DP is triggered for the O(B-C) relationship and the T_Answer DP is triggered for the T(A-B) relationship. For each DP, an EventReportBCSM message is sent to the SCF. At this point, the SCF may begin charging for the call. The ActivityTest message continues to be sent periodically throughout the life of the forwarded call.

Note:

In case the forwarded call is not allowed, a ReleaseCall message is sent to the SSP.

Late Call Forwarding (Conditional Call forwarding i.e. when busy, No answer, Not Reachable encountered)

In this scenario the call is forwarded to C-Party Number after Busy, No Answer, or Not Reachable situation has encountered) i.e. the called subscriber (B-party) has CF on Busy, No Answer enabled, receives a call, the CF condition is met and CF is handled in the MSC.Signalling Flow


Explanation:The GMSC sends this T-CSI to the SCF (service control function) in the initial DP message indicating that a TDP-R (trigger detection point request) has been set for the prepaid subscriber at the terminating_attempt _authorized PIC (point in call) as shown in the BCSM (Basic call state model, section 4.5.2).


When the call is authorized, the SCF sends the RequestReportBCSMEvent, ApplyCharging and Continue message to the SSF. The RequestReportBCSMEvent arms triggers for when the call is answered or terminated. It specifics the triggers that GMSC needs to monitor and notify. The SCF sends an Apply Charging message with the maxCallPeriodDuration and releaseIfduration Exceeded parameters set to instruct the MSC to release the call when the maximum call duration is reached and to play a warning tone prior to release. Also, the continue message instructs the GMSC to continue with the processing without waiting for further instructions from SCF.

If the call encounters a CF condition due to subscriber Busy or No Answer in the MSC, the MSC creates a new O(B-C) relationship for the forwarded call. As the PPS subscriber is also an Originating subscriber, a TDP-R is set for the prepaid subscriber at the collected_info PIC and SSF sends Initial DP again with O_CSI embeded in it.

When the SCF receives the InitialDP message, it analyzes the type of call. If the Redirection Information parameter is present, it is a forwarded call. If a Redirecting Party ID is present the SCF uses this information to determine the status of the PPS account. If the account is valid, further analysis takes place.

If the Forwarding Party (PPS subscriber) is authorized to call the destination address, and if the subscribers balance is sufficient to permit the call, the SCF sends the RequestReportBCSMEvent and Continue and message to the SSF. If the forwarded call is chargeable, the SCF also sends an ApplyCharging message with maxCallPeriodDuration and releaseIfdurationExceeded parameters. The RequestReportBCSMEvent arms triggers for when the call is answered or terminated.

The SSF then continues with normal call establishment until the called party answers the call. The SCF begins an ActivityTest timer (TActTest), whose expiration causes an ActivityTest message to be periodically sent to the SSF. This is used to ensure that the dialog is still active at the SSF.

When the forwarded call is answered, the oAnswer DP is triggered for the O (B-C) relationship and the T_Answer DP is triggered for the T (A-B) relationship. For each DP, an EventReportBCSM message is sent to the SCF. At this point, the SCF may begin charging for the call.The ActivityTest message continues to be sent periodically throughout the life of the forwarded call.

Note: In case the forwarded call is not allowed, a ReleaseCall message is sent to the SSF.

3.7 Annexure3.7.1 Description of CAMEL BCSMsGeneral Handling

The BCSM is used to describe the actions in an MSC/GMSC/VMSC during originating, forwarded or terminating calls. The BCSM identifies the points in basic call processing when Operator Specific Service (OSS) logic instances (accessed through the GSMSCF) are permitted to interact with basic call control capabilities.

Originating Basic Call State Model (O-BCSM)

Description of O-BCSM

The O-BCSM is used to describe the actions in an MSC during originating (MSC) or forwarded (MSC or GMSC) calls. When encountering a DP the O-BCSM processing is suspended at the DP and the MSC/GMSC indicates this to the GSMSSF which determines what action, if any, shall be taken in case the DP is armed.

Terminating Basic Call State Model (T-BCSM)

Description of T-BCSM

The T-BCSM is used to describe the actions in a GMSC and in a VMSC during terminating calls.

When encountering a DP the T-BCSM processing is suspended at the DP and the GMSC / VMSC indicates this to the GSMSSF which determines what action, if any, shall be taken in case the DP is armed.

In the following table the different DPs (in the T-BCSM) are described.

3.7.2 Description of information flow (Camel Phase Application Part) From SCF to SSF

1. Activity Test

Description - This is used to check for the continued existence of a relationship between the GSM SCF and GSM SSF. If the relationship is still in existence, then the GSM SSF will respond. If no reply is received, then the GSM SCF will assume that the GSM SSF has failed in some way and will take the appropriate action.

Parameters - This message contains no information elements.

2. Apply charging

Description - This is used for interacting from the GSM SCF with the GSM SSF charging mechanisms to control the call duration.Parameter The information elements contained in this parameter are stated as follow

Information ElementsDescription

1. Max Call Period DurationThis IE indicates the maximum call period duration timer

2. Tariff Switch IntervalThis IE indicates the tariff switch time until the next tariff switch applies.

3. Release If Duration ExceededThis IE indicates that the call shall be released when the Max call Period Duration expires, with a warning tone if the Play Tone IE is present. The cause used in the release message shall be "normal unspecified".

Default is to continue the call.

4. Play ToneThis IE is set if a tone has to be played to the party for whom the BCSM is operating. If present, this IE indicates that 30 seconds before the Max Call Period Duration timer expires,

a triple tone of 900 Hz (200 milliseconds tone, 200 milliseconds pause) shall be played

5. Party To ChargeThis IE shall be reflected in the corresponding IE of the Apply Charging Report operation. This IE has no effect on the charging procedures in the MSC.

3. Connect To Resource Description - This is used to connect a call from the GSM SSF to GSM SRF.Parameters - The information elements contained in this parameter are stated as follow

Information ElementDescription

1. Service Interaction IndicatorsThis parameter indicates whether or not a both way through connection is required between the Calling party and the gsmSRF.

2. IP Routing AddressThis IE indicates the routing address to set up a connection towards the gsmSRF.

3. NoneThis parameter indicates that the call party is to be connected to a predefined gsmSRF

1. Continue

Description - This IF requests the GSM SSF to proceed with call processing at the DP at which it previously suspended call processing to await GSM SCF instructions. The GSM SSF completes DP processing, and continues basic call processing.

Parameters - This message contains no information elements.

2. Disconnect Forward Connection

Description - This IF is used :- to disconnect a connection with a GSMSRF previously established with a Connect To Resource IF;- to disconnect an initiating GSM SSF from an assisting GSM SSF and its associated GSM SRF. The IF is send to the initiating GSM SSF.Parameters - This message contains no information elements.

3. Establish Temporary ConnectionDescription - This IF is used to create a connection between an initiating GSM SSF and an assisting GSM SSF as a part of the assist procedure. It can also be used to create a connection between a GSM SSF and a GSM SRF.Parameters - The information elements contained in this parameter are stated as follow

Information ElementsDescription

1.Assisting SSP IP Routing AddressThis parameter indicates the destination address of the gsmSRF or assisting gsmSSF for the assist procedure. As a network operator option, the Assisting SSP IP Routing Address may contain embedded within it, a "Correlation ID" and " Scf ID", but only if "Correlation ID" and "Scf ID" are not specified separately.

2. Correlation IDThis parameter is used for :

- the correlation of dialogues from the initiating gsmSSF-

gsmSCF with dialogues from gsmSRF -> gsmSCF

- the correlation of dialogues from the initiating gsmSSF-

gsmSCF with dialogues from assisting gsmSSF -gsmSCF

3. NA Carrier InfoThis IE is described in the next table.

4. NA Originating Line InformationThis IE identifies the type of number in the NA Charge

Number (e.g. subscriber versus PLMN operator number).

5.NA Charge No.This IE identifies the chargeable number for the usage of a North American carrier.

6. Scf IDThis parameter indicates the gsmSCF identifier

7. Service Interaction Indicators TwoThis parameter indicates whether or not a both way

through connection is required between the Calling party and the GSM SRF

NA Carrier Information contains the following information:Information ElementDescription

NA Carrier Identification CodeThis IE uniquely identifies a North American long distance carrier.

NA Carrier Selection

InformationThis IE indicates the way the carrier was selected e.g.:

dialed

subscribed

4. Release Call

Description - This IF is used to tear down by the gsmSCF an existing call at any phase of the call for all parties involved in the call.Parameters - The information elements contained in this parameter are stated as follow


Release CauseA number giving an indication to the gsmSSF about the reason of releasing this specific call. This may be used by MSC/GMSC for generating specific tones to the different parties in the call or to fill in the "cause" in the release message.

5. Request Report BCSM Event

Description - This IF is used to request the gsmSSF to monitor for a call-related event, and then send a notification back to the gsmSCF when the event is detected.

Parameters - The information elements contained in this parameter are stated as follow


BCSM EventThis IE specifies the event or events of which a report is requested

BCSM Event contains the following information.


Event typeThis IE specifies the type of event of which a report is requested.

Leg IDThis IE indicates the party in the call for which the eventshall be reported

Monitor ModeWhen this IE is "interrupted", the event shall be reported

as a request, if it is "notify And Continue", the event shallbe reported as a notification, if the IE is "transparent", the event shall not be reported.

DP Specific Criteria

(Application Timer)This IE carries additional timer duration information

(timer values for No Answer event) required for arming

No_Answer EDPs in the gsmSSF. The TNRy timer (value defined between 10s and 40s) shall be shorter than the network no answer timer

6. Reset TimerDescription - This IF is used to refresh a timer.



Timer ValueThis IE specifies the value to which the indicated timer

shall be set

Timer IDThis IE indicates which timer shall be reset. It shall be

set to Tssf.

From SSF to SCF

1. Activity Test ack

Description This IF is the response to the Activity Test.

Parameter - This IF contains no information elements.2. Apply Charging Report

Description - This IF is used by the gsmSSF to report to the gsmSCF the information requested in the Apply Charging IF.



Call ResultThis IE contains the charging information to be provided

by the gsmSSF

Call Result contains the following informationInformation ElementDescription

Time InformationThis IE is a choice between Time if No Tariff Switch and

Time if Tariff Switch.

Party To ChargeThis IE is received in the related Apply Charging operation to correlate the result to the request. This IE shall be a copy of the corresponding IE received in the Apply Charging operation.

Call ActiveThis IE indicates whether the call is active or not.

Call Released at Tcp ExpiryThis element is an indication that the gsmSSF has

released the call and terminated the dialogue, due to

Tcp expiry. It shall be present when ACR is sent due to Tcp expiry and the gsmSSF has released the call

(because ReleaseIfExceeded was present in ACH

operation).In all other circumstances, this element shall be absent

Time If No Tariff SwitchThis IE will be present if no tariff switch has occurred

since the detection of Answer for the connection to the

Called Party, the Temporary Connection, or the SRF

Connection, otherwise it will be absent.

Time If Tariff SwitchThis IE will be present if a tariff switch has occurred since the detection of Answer for the connection to the Called Party, the Temporary Connection, or the SRF connection, Otherwise it will be absent.

3. Event Report BCSM

Description - This IF is used to notify the gsmSCF of a call-related event (i.e., BCSM events as answer and disconnect) previously requested by the gsmSCF in a Request Report BCSM Event IF.


The following information elements are required:


Event type BCSMThis IE specifies the type of event that is reported.

Event Specific Information BCSMThis IE indicates the call related information specific to

the event

Leg IDThis IE indicates the party in the call for which the event

is reported.

Misc Call InfoThis IE indicates the DP type

Event Specific Information BCSM contains the following information for the O Answer and T Answer casesInformation ElementDescription

Destination addressThis IE specifies the destination address for the call leg

ORThis IE indicates that the call was subject to basic

Optimal Routing

Forwarded callThis IE indicates that the call has been subject to GSM

Call forwarding.

4. Initial DP

Description - This IF is generated by the gsmSSF when a trigger is detected at a DP in the BCSM, to request instructions from the gsmSCF.Parameter - The information elements contained in this parameter are stated as follow


Additional Calling Party

NumberThe calling party number provided by the access signaling system of the calling user.

Bearer CapabilityThis IE indicates the type of the bearer capability

connection to the user

Called Party NumberThis IE contains the number used to identify the called party in the forward direction. For the VT calls this is the MSISDN received in the Provide Roaming Number; if the MSISDN is not available, the basic MSISDN is used

Called Party BCD NumberThis IE contains the number used to identify the called party in the forward direction. The number contained in this IE shall be identical to the number received over the access network. It may e.g. include service selection information, such as and # digits, or carrier selection information dialed by the subscriber.

Calling Party NumberThis IE carries the calling party number to identify the calling party or the origin of the call

Calling Party CategoryIndicates the type of calling party (e.g., operator, pay phone, ordinary subscriber).

Call Gap EncounteredThis parameter indicates the type of gapping the related call have been subjected to.

This parameter shall be present only if a call gapping context is applicable to the initialDP operation.



Call Reference NumberThis IE may be used by the gsmSCF for inclusion in a network optional gsmSCF call record. It has to be coupled with the identity of the MSC which allocated it in order to define unambiguously the identity of the call.

For MO calls, the call reference number is set by the

serving VMSC and included in the MO call record.

For MT calls, the call reference number is set by the

GMSC and included in the RCF call record in the GMSC and in the MT call record in the terminating MSC.

For VT calls, the call reference number is set by the

GMSC and included in the RCF call record in the GMSC and in the MT call record in the terminating MSC.

For CF calls, the call reference number is set by the GMSC and included in the CF record in the forwarding MSC.

CauseThis IE indicates the cause specific to the armed BCSM DP event. This IE is applicable to DP

Route_Select_Failure and DP T_Busy. The cause may be used by the SCF to decide about the further handling of the call.

Event Type BCSMThis IE indicates the armed BCSM DP event, resulting in the Initial DP IF.

Ext-Basic Service CodeThis IE indicates the type of basic service i.e., tele service or bearer service.

High Layer CompatibilityThis IE indicates the type of the high layer compatibility, which will be used to determine the ISDN-teleservice of a connected ISDN terminal

IMSIThis IE identifies the mobile subscriber

IP SSP CapabilitiesThis IE indicates which SRF resources are supported within the gsmSSF and are available. If this IE is absent, this indicates that no gsmSRF is attached and available

Location InformationThis indicates the current location of the mobile subscriber,

Location NumberFor mobile originated calls this IE represents the location of the calling party. For all other call scenarios this IE contains the location number received in incoming ISUP signaling

MSC AddressFor MO calls, the MSC Address carries the international E.164 address of the serving VMSC.

For MT calls, the MSC Address carries the international E.164 address of the GMSC.

For VT calls, the MSC Address carries the international E.164 address of the serving VMSC.

For CF calls, the MSC Address carries the international E.164 address of the forwarding MSC.

GMSC AddressFor CF calls, the GMSC Address carries the international E.164 address of the GMSC.

For VT calls, the GMSC Address carries the international E.164 address of the GMSC



NA Carrier InformationThe IE may be sent when the VPLMN and the HPLMN of the subscriber are both North American.

For MO calls, this IE shall contain any carrier that was dialed by the calling subscriber. If no carrier was dialed, the IE shall contain the calling subscribers subscribed carrier.

For MT and VT calls, the IE shall contain the carrier

Subscribed to by the called subscriber.

For CF calls, the IE shall contain the carrier subscribed to by the forwarding subscriber

Original Called Party IDThis IE carries the dialled digits if the call has met call forwarding on the route to the gsmSSF

Redirecting Party IDThis IE indicates the directory number the call was

Redirected from.

Redirection InformationThis IE contains forwarding related information, such as redirection counter

Service KeyThis IE indicates to the gsmSCF the requested CAMEL Service. It is used to address the required application/SLP within the gsmSCF.

Subscriber StateThis IE indicates the status of the MS. The states are:- CAMELBusy: The MS is engaged on a transaction for a mobile originating or terminated circuit-switched call.

- NetworkDeterminedNotReachable: The network can determine from its internal data that the MS is not reachable.

- AssumedIdle:The state of the MS is neither

"CAMEL Busy" nor "NetworkDeterminedNot Reachable".

- Not provided from VLR

Time And TimezoneThis IE contains the time that the gsmSSF was triggered, and the time zone the gsmSSF resides in.

GSM Forwarding PendingThis parameter indicates that a forwarded-to-number was received and the call will be forwarded due to GSM supplementary service call forwarding in the GMSC/VMSC

Service Interaction Indicators TwoThis IE is sent if it is received in the ISUP message or due to previous CAMEL processing

From SCF to SRF1. Activity Test

Description - This IF is used to check for the continued existence of a relationship between the gsmSCF and gsmSRF. If the relationship is still in existence, then the gsmSRF will respond. If no reply is received, then the gsmSCF will assume that the gsmSRF has failed in some way and will take the appropriate action.

Parameter - This IF contains no information elements.2. Cancel

Description - This IF is used by the gsmSCF to request the gsmSRF to cancel a correlated previous operation.

Parameter - The information elements contained in this parameter are stated as follow.


Invoke IDThis IE specifies the operation to be cancelled

3. Play AnnouncementDescription - This IF is used for inband interactionParameter - The information elements contained in this parameter are stated as followInformation ElementDescription

Information To SendThis IE indicates an announcement or a tone to be sent

to the end user by the gsmSRF

Disconnect From IP ForbiddenThis IE indicates whether or not the gsmSRF may be

disconnected from the user when all information hasbeen sent

Request Announcement

CompleteThis IE indicates whether or not a Specialized Resource Report shall be sent to the gsmSCF when all information has been sent.

Information to Send contains the following informationInformation ElementDescription

Inband InfoThis IE indicates the inband information to be sent

ToneThis IE indicates the tone to be sent. The mapping from the code points of this IE to tones is a matter for

agreement between the gsmSCF operator and the gsmSRFoperator

Inband Info contains the following informationMessage IDThis IE is described in the next table.

Number Of RepetitionsThis IE indicates the maximum number of times the

message shall be sent to the end-user.

DurationThis IE indicates the maximum duration time in seconds

that the message shall be played/repeated. Zero indicates

endless repetition

Interval

This IE indicates the time interval in seconds between two

repetitions.

Message ID contains the following information:

Information elementDescription

Elementary Message ID

This IE indicates a single announcement

Text

This IE indicates a text to be sent. The text shall be

transformed to inband information (speech) by the

gsmSRF.

Elementary Message IDsThis IE indicates a sequence of announcements

Variable MessageThis IE indicates an announcement with one or more

variable parts

Tone contains the following information.Information ElementDescription

Tone IDThis IE indicates the tone to be sent.

DurationThis IE indicates the maximum duration time in seconds

that the message shall be played/repeated. Zero indicates endless repetition

From GSM SRF to GSM SCF

1. Activity Test ack

Description - This IF is the response to the Activity Test.

Parameter - This IF contains no information elements.2. Specialized Resource ReportDescription - This IF is used to response to a Play Announcement IF when the announcement complete indication is set.Parameter - This IF contains no information elements.From HLR to VLR 1. Delete Subscriber Data Description - This IF is used by an HLR to remove certain subscriber data from a VLR if the subscription of one or more supplementary services or basic services is withdrawn.Parameter - The Delete Subscriber Data contains the following CAMEL specific IEInformation ElementDescription

CAMEL Subscription Info

WithdrawThis IE identifies that all CSIs shall be deleted from the subscriber data in

VLR.

2. Insert Subscriber Data

Description - This IF is used by an HLR to update a VLR with certain subscriber data.

Parameter - Insert Subscriber Data contains the following CAMEL specific IE:InformationElementDescription

O-CSIThis IE identifies the subscriber as having originating CAMEL services

D-CSIThis IE identifies the subscriber as having originating CAMEL dialed services

VT-CSIThis IE identifies the subscriber as having terminating CAMEL services in the VMSC

O-CSID-CSIVT-CSI

GSM SCF AddressGSM SCF AddressGSM SCF Address

Service KeyService KeyService Key

Default Call HandlingDefault Call HandlingDefault Call Handling

TDP List_TDP List

DP CriteriaDP CriteriaDP Criteria

CAMEL Capability HandlingCAMEL Capability HandlingCAMEL Capability Handling

3. Provide Roaming NumberDescription This IF is used by the HLR to request a roaming number from the VLR.

Parameter - Provide Roaming Number contains the following CAMEL specific IE.


Suppression Of AnnouncementsThis IE indicates that announcements or tones generated as a result of unsuccessful call setup shall be suppressed.

Call Reference NumberThis IE carries the Call Reference Number provided by the GMSC in the Send Routing Info IF

GMSC AddressThis IE is the E.164 address of the GMSC

Alerting PatternThis IE indicates the kind of Alerting Pattern to be applied

GMSC CAMEL PhasesThis IE indicates the CAMEL Phases supported in the GMSC.

From VLR to HLR

1. Insert Subscriber Data ack

Description This IF is used by the VLR to indicate to the HLR the result of the Insert Subscriber Data IF.

Parameter - Insert Subscriber Data ack contains the following CAMEL specific IEInformation ElementDescription

Supported CAMEL PhasesThis IE identifies which CAMEL phases are supported by the MSC/VLR

2. Update LocationDescription This IF is used by the VLR to provide the information about supported CAMEL phases to the HLR.

Parameter - Update Location contains the following CAMEL specific IE:


Supported CAMEL phasesThis IE indicates which phases of CAMEL are supported. It shall be present if a CAMEL phase different from phase 1 is supported.

Otherwise may be absent

From HLR to GMSC

1. Send Routing Info ack

Description This IF is used by the HLR to transfer the requested routing information to the GMSC.Parameter - Send Routing Info ack contains the following CAMEL specific IE:Information ElementDescription

Location InformationThis IE indicates the location of the served subscriber.

O-CSIThis IE identifies the subscriber as having originating CAMEL services.Shall be sent if O-CSI is active, or if both O-CSI and T-CSI are active.

Subscriber StateThis IE indicates the status of the MS. The possible values of the

IE are:

- CAMELBusy: The VLR has indicated that the MS is engaged on a transaction for a mobile originating or terminated circuit-switched call.

- NetworkDeterminedNotReachable: The VLR has indicated that the network can determine from its internal data that the MS is not reachable.

- AssumedIdle: The VLR has indicated that the state of the MS is neither "CAMELBusy" nor "NetworkDeterminedNotReachable".

- NotProvidedFromVLR: The VLR did not provide any information on subscriber state even though it was requested.

T-CSIThis IE identifies the subscriber as having terminating CAMEL services. Shall be sent if T-CSI is active and no Suppress T-CSI indicator is present in the SRI.

Basic Service CodeThis IE indicates the type of basic service i.e., tele service or bearer service.

CUG Subscription FlagThis IE indicates if the called party has a CUG subscription. It shall only be sent if the T-CSI is active and included in the Send Routing Information ack.

Location Information contains the following information

Information Element Description

Location NumberThe IE shall be sent, if available and indicated by Subscriber Information in Send Routing Information ack indicator

CellGlobalIdOrServiceAreaId

OrLAIThe IE shall be sent, if available and indicated by Subscriber Information in Send Routing Information ack indicator.

Geographical InformationThe IE shall be sent, if available and indicated by Subscriber Information in Send Routing Information ack indicator.

Geodetic InformationThe IE shall be sent, if available and indicated by Subscriber Information in Send Routing Information ack indicator

Age Of Location InformationThe IE shall be sent, if available and indicated by Subscriber Information in Send Routing Information ack indicator

VLR numberThe IE shall be sent, if available and indicated by Subscriber Information in Send Routing Information ack indicator

Selected LSA IdentityThe IE shall be sent, if available and indicate by Subscriber Information in Send Routing Information ack indicator

From GMSC to HLR

1. Send Routing Info Description - This IF is used to request information from the HLR to route an MT call.

Parameter - Send Routing Info contains the following CAMEL specific IE:


Alerting PatternThis IE indicates the kind of Alerting Pattern to be applied.

Suppression Of AnnouncementThis IE indicates that announcements or tones generated as a result of unsuccessful call setup shall be suppressed. Shall be sent in the second interrogation if available, i.e., when it has been received from the GSM SCF.

Suppress T-CSIThis IE indicates that T-CSI shall be suppressed. Shall always be sent in the second interrogation

Supported CAMEL PhasesThis IE lists the supported CAMEL phases.

Call Reference NumberThis IE carries the Call Reference Number allocated for the call by the GMSC. Shall be allocated once per call and sent in both first and second interrogations


Call Diversion Treatment IndicatorThis IE indicates if the call can be forwarded using the Call Forwarding or Call Deflection Supplementary Services. Shall be sent if received within Forward Service Interaction

Indicator in Service Interaction Indicators Two from IAM or previous CAMEL processing.

From VMSC to GMSC

1. Resume Call Handling

Description - This IF is used to request the GMSC to take over handling the call so that it can be forwarded from the GMSC.

Parameter OCSI and DCSIFrom MSC to VLR.

1. Send Info for Outgoing Call

Description This IF is used to request the VLR to provide information to handle an outgoing call.

Parameter - Send Info For Outgoing Call contains the following CAMEL specific IE.


Suppress O-CSIThis IE indicates that O-CSI shall be suppressed.

Shall always be sent in the second interrogation.

Suppress D-CSIThis IE indicates that D-CSI shall be suppressed.

Shall always be sent in the second interrogation.

N-CSI availableThis IE indicates that N-CSI is available in MSC.

Shall be sent in the first interrogation if N-CSI is available in

MSC.

2. Send Info for Reconnected CallDescription - This IF is used to request the VLR to provide information to handle a reconnected call.

Parameter - Send Info For Reconnected Call contains the following IEInformation ElementDescription

Called numberE.164 number of the call destination.

Bearer serviceBearer service required for the MO call, derived from the GSM bearer capability information received in the setup request from the MS. One of bearer service or teleservice shall be present.

Tele serviceTele service required for the MO call, derived from the GSM bearer capability information received in the setup request from the MS or from the emergency setup request from the MS. One of bearer service or tele service shall be present

CUG indexShall be present if it was received in the setup request from the MS.

Suppress O-CSIThis IE indicates that O-CSI shall be suppressed. Shall always be sent in the second interrogation

From VLR to MSC

1. Complete CallDescription This IF is used to instruct the MSC to continue the connection of a call

Parameter - Complete Call contains the following CAMEL specific IE:Information ElementDescription

O-CSIThis IE indicates that CAMEL handling applies for an MO call. Shall be present in the response to the first interrogation for an

MO call if CAMEL handling applies otherwise shall be absent. Shall be absent in the response to the second interrogation for an MO call and in the response to the interrogation for an MT call

D-CSIThis IE identifies the subscriber as having originating CAMEL dialed services

VT-CSIThis IE identifies the subscriber as having terminating CAMEL services in the VMSC

Call Reference NumberThis IE carries the Call Reference Number provided by the HLR in the Provide Roaming Number IF


2. Process Call WaitingDescription This IF is used to instruct the MSC to continue the connection of a waiting call.

Parameter - Process Call Waiting contains the following CAMEL specific IE:Information Element Description

Call Reference NumberThis IE carries the Call Reference Number provided by the HLR in the Provide Roaming Number IF.

GMSC AddressThis IE is the E.164 address of the GMSC.

3. Send Info For Incoming Call ackDescription This IF is used to indicate that the incoming call for which the MSC requested subscription information shall be forwarded.

Parameter - Send Info For Incoming Call ack contains the following CAMEL specific IE:Information Element Description

O-CSIThis IE indicates that CAMEL handling applies for a forwarded call. Shall be present if CAMEL handling applies; otherwise shall be absent.

VT-CSIThis IE identifies the subscriber as having terminating CAMEL services in the VMSC.

Suppression Of AnnouncementThis IE indicates that announcements or tones generated when the call is forwarded shall be suppressed. Shall be sent if it was received in the Provide Roaming Number

for this call

Call Reference NumberThis IE carries the Call Reference Number provided by the HLR in the Provide Roaming Number IF.

GMSC AddressThis IE is the E.164 address of the GMSC.

4. Send Info for Incoming Call negative responseDescription This IF is used to indicate that the incoming call for which the MSC requested subscription information shall not be connected.Parameter - Send Info for Incoming Call negative response contains the following CAMEL specific IEInformation Element Description

Suppression Of AnnouncementThis IE indicates that announcements or tones generated as a result of unsuccessful call setup shall be suppressed. Shall be sent if it was received in the Provide Roaming Number for this call.

HLR

VLR

Registration Process

O-CSI

GMSC

HLR

T-CSI

SSF

Initial DP (O CSI)

RRBE (O_ANSWER, O_DISCONNECT, O_BUSY,O_ABANDON )

Continue, Apply Charging

ERB (O_ANSWER Encountered)

Activity Test (O_ACTIVE)

Activity test _ack

ERB (O_DISCONNECT Encountered)

Apply Charging Report

VOICE TRANSMISSION

VOICE TRANSMISSION

Release Call

SCF

SSF

SCF

IP/SRF

Initial DP (O CSI)

RRBE (O_DISCONNECT,O_ABANDON )

CONNECT TO RESOURCE

PLAY AN ANNOUCEMENT

ANNOUCEMENT PLAYED TO THE SUSCRIBER

SPECIALIZED RESOURCE REPORT

DISCONNECT FORWARD CONNECTION

RRBE (O_DISCONNECT,O_ANSWER )

Continue, Apply Charging

ERB (O_ANSWER Encountered)

ERB (O_DISCONNECT Encountered)


IAM

ACM

ANM

VOICE TRANSMISSION

Release Call

SSF

SCF

Initial DP (O CSI)

RRBE (O_DISCONNECT,O_ABANDON,O_ANSWER,O_BUSY,O_NOANSWER )

APPLY CHARGING, CONTINUE

O_ABANDON ENCOUNTERED


RELEASE CALL

SSF

SCF

IP/SRF

Initial DP (O CSI)

RRBE (O_DISCONNECT,O_ABANDON )

CONNECT TO RESOURCE

PLAY AN ANNOUCEMENT

ANNOUCEMENT PLAYED TO THE SUSCRIBER



IAM

ACM

ANM

Release Call

GMSC

SCF

HLR

VLR

VMSC

SRI

SRI-ACK (T-CSI)

Initial DP (TCSI)

RRBE (T_DISCONNECT, T_ABANDON, T_ANSWER,T_BUSY,T_NOANSWER )

APPLY CHARGING, CONTINUE

TCSI SUPRESS

PROVIDE ROUTING NUMBER (PRN)

MSRN (PRN-ACK)

MSRN

IAM

ACM

ANM

T_ANSWER ENCOUNTERED

T_DISCONNECT

CHARGING REPORT

VOICE TRANSMISSION

IAM

SCF

IP / SRF

ERROR ANNOUCEMENT PLAYED

MSC/SSF

RLC

REL

ANM

ACM

IAM

RELEASE CALL


Reset Timer

PLAY ANNOUCEMENT

CONTINUE

ESTABLISH TEMPORARY CONNECTION

RRBE (O_ABANDON, O_DISCONNECT)

INITIAL DP


SSF

SCF

INITIAL DP

RRBE (O_ABANDON, O_DISCONNECT,O_ANSWER,O_BUSY)

APPLY CHARGE (MAX CALLDURATION, PLAY WARNING TONE, IF EXCEEDS)

O_ANSWER ENCOUNTERED

Continue ,Activity Test(O_active)

T ACT TEST _TIMER Expires

Activity Test Ack


Activity Test Ack

Play announcement

Warning tone Played to the caller


End ,

SSF

SCF

INITIAL DP

RRBE (O_ABANDON, O_DISCONNECT,O_ANSWER,O_BUSY)

APPLY CHARGE (MAX CALLDURATION, PLAY WARNING TONE, IF EXCEEDS)

O_ANSWER ENCOUNTERED


T ACT TEST _TIMER Expires

Activity Test Ack


Activity Test Ack

Release Call


End ,

SSF

SCF

Initial DP (T-CSI)

Initial DP (O-CSI)

Activity Test Ack

T ACTTEST_TIMER

Expires

RRBE (T_ABANDON, T_DISCONNECT)

CONTINUE

CONTINUE

RRBE (O_ANSWER, O_DISCONNECT,O_BUSY,O_ABANDON)

ERBE (O_ANSWER ENCOUNTERED)

ERBE (O_DISCONNECT ENCOUNTERED)

Apply Charging

Apply Charging

Release Call


SSF

SCF

Initial DP (T-CSI)

Initial DP (O-CSI)

Activity Test Ack

RRBE (T_ABANDON, T_DISCONNECT,T-ANSWER,T_BUSY,T-NO ANSWER)

CONTINUE

CONTINUE

RRBE (O_ANSWER, O_DISCONNECT,O_BUSY,O_ABANDON)

ERBE (O_ANSWER ENCOUNTERED)

ERBE (O_DISCONNECT ENCOUNTERED)

Apply Charging

Apply Charging

T ACTTEST_TIMER

Expires

ERBE (T_BUSY ENCOUNTERED)

Release Call


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Camel Phase 3