In Call Flow

CAMEL stands for: Customized Application for Mobile-Network Enhanced Logic.

CAMEL is a mechanism which allows: • Flexible creation of operator specific services, • Each subscriber to have customised services, • Deployment of those services to roaming subscribers.

CAMEL is sometimes referred to as GSM IN (Intelligent Networks).

CAMEL Phase 1 was defined in GSM '96 Release.

CAMEL has been included as a mandatory feature on MoU requirements list.

CAMEL phase 1 is being followed by CAMEL phase 2 and phase 3 in GSM'97 Release and GSM '99 Release respectively.

CAMEL CONCEPT

CAMEL Nodes And Interfaces

HLR gsmSCFMAP

CAP

CAMELApplication Part

GSM Service Control Function -

GSM SCF Contains the service logic and provides

instructions on how to continue call processing

Home Location Register -HLR can store CAMEL

Subscription Information (CSI)on a per subscriber basis

VMSC/

GMSC

SSF

GSM Service SwitchingFunction - gsmSSF, suspends

call processing and takesinstructions from the SCF

Mobile Station - MSdoes not require anyCAMEL functionality

MAP

Normal Mobile to Mobile GSM Call Setup

HLR B

GMSCB

VMSCB

SETUPSETUP

ISUP ISUP

SRI Ack

PRN Ack

87

6

5

4

3

2

1

Provide Roaming Number

SendRouting

Info

VMSCA

VLRA

AB

VLRB

CAMEL DETECTION POINTS (DPs) - 1B/4

• Detection Points are points in processing at which notifications (to the

service logic) can occur and transfer of control (to the gsmSCF) is possible.

• 3 Different types of DPs exist:

• TDP-R: Trigger Detection Point - Request

This DP is statically armed and initiates a CAMEL control relationship

when encountered. Processing is suspended when the DP is

encountered.• EDP-R: Event Detection Point - Request

This DP is dynamically armed within the context of a CAMEL control

relationship. Processing is suspended awaiting instructions from the

gsmSCF when encountering the DP.• EDP-N: Event Detection Point - Notification

This DP is dynamically armed within the context of a CAMEL control

relationship. Processing is not suspended when encountering the DP.

CAMEL DPs and BCSMs - 2B/4

• Detection Points are associated with the concept of Basic Call State

Machines (BCSMs).

Transition• BCSM identifies the points in basic call processing when

Operator Specific Service logic instances (accessed through

the gsmSCF) are permitted to interact with basic call control

capabilities.• BCSM processing is suspended when encountering a DP

until further instruction is given from the gsmSCF.

• BCSM is a high level model used to describe the actions in a GMSC or

MSC/VLR during originating, forwarded or terminated calls.

Point In Call(PIC)

BCSM gsmSSF gsmSCF

Call processing Switching Centre Control Centre

MSC/ GMSC

DP

DP

CAMEL Originating-BCSM - 3B/4

Analyse, Routing & Alerting

O-Null & Authorise_Origination_Attempt_Collect_Info

O-Exception

DP2

O-Active

DP7

DP9

Collect_Info

O_AnswerO_Disconnect

CAMEL Detection Point DP Type Description

DP2 Collect_Info TDP-R Indication that the O-CSI is analysed

DP7 O_Answer EDP-N Indication that the call is accepted andanswered by the terminating party

DP9 O_Disconnect EDP-N,EDP-R

A disconnect indication is received fromthe originating party or from theterminating party

O-BCSM in the MSC/ GMSC

CAMEL Terminating-BCSM - 4B/4

Terminating Call Handling

T-Null T-Exception

DP12

T-Active

DP15

DP17

Terminating_Attempt_Authorised

T_AnswerT_Disconnect

CAMEL Detection Point DP Type Description

DP12 Terminating_Attempt_Authorised

TDP-R Indication that the T-CSI is analysed

DP15 T_Answer EDP-N Call is accepted and answered by theterminating party

DP17 T_Disconnect EDP-N,EDP-R

A disconnect indication is received fromthe originating party or from theterminating party

T-BCSM in the GMSC

User profile for Time Dependent Routing

entered into SCF

HLR

gsmSCF

Info sent to HLR toprovision CSI data for

TDR for this subscriber

I would like my callsto be directed to my mobile

every afternoon

Administrator

• To provision CAMEL, CSI is provided by the HPLMN operator by administrator means.

• CSI identifies if the subscriber requires CAMEL support.• CSI identifies which gsmSCF to use for that CAMEL support.• CSI contains information related to the Operator Specific Service (OSS) of the subscriber, for example the Service Key.

CAMEL SUBSCRIPTION INFORMATION (CSI) - 1A/3

OK

• Terminating-CSI identifies subscriber as having terminating CAMEL Services. T-CSI is fetched by the GMSC when the HLR of the called subscriber is being interrogated by the GMSC.• Originating-CSI is sent to the GMSC for forwarding.

Originating and Terminating CSI - 2A/3

HLR

ISUP

SRI Ack

SendRouting Info

GMSCB

SSF

VMSCA

VLRA

HLR sends CAMELprofile - CSI - in

SRI Ack to the GMSC

VMSCA

VLRA

SSF

ISUP

HLR

GMSCBSETUP

CSI in Location Update

• Originating-CSI identifies subscriber as having originating CAMEL Services. O-CSI is stored in the VLR as part of subscriber data for roaming subscriber in the VLR area.

CSI CONTENT - 3A/3

• gsmSCF address as an E.164 number

• Service Key which identifies to the gsmSCF the service logic that should be used.

• Default call handling that indicates how to proceed the call in case of error in the

gsmSSF - gsmSCF dialogue (release or continue).

• TDP list that indicates on which Detection Point (DP) triggering shall

take place. Only DP2 for O-CSI and only DP12 for T-CSI.

Mobile Originated Call Setup With CAMEL

GMSCB

VMSCA

VLRA

SETUP 1234

1

ISUP

Initial DP 1234CO

NNECT 01654 456789

2

3

4

gsmSCF

SSFSSF

A

Mobile Terminated Call Setup With CAMEL

HLR

GMSCB

VMSCA

VLRA

SETUP 1234

1

ISUP

Initial DP 1234CO

NNECT 01654 456789

2

3

4

gsmSCF

gsmSCF

SRI Ack

6

5Send Routing

Info

Initial D

P CONTINUE

8

7

SSFSSF

A

VMSCBISUP

SETUP

VLRB

B

13

14

PRN Ack

11

10Provide Roaming Number

9

12

Complete Call Setup With CAMEL Invoked By Both Parties

HLR

GMSCB

VMSCB

VMSCA

VLRA

SETUP 1234

1

ISUP

Initial DP 1234CO

NNECT 01654 456789

2

3

4

gsmSCF

gsmSCF

SRI Ack

6

5Send Routing

Info

Initial D

P CONTINUE

8

7

ISUP

PRN Ack

11

10Provide Roaming Number

9

SETUP

14

12

13

SSFSSF

VLRB

BA

MO CAMEL Call Setup - VPN Example

VMSCA

VLRA

GMSCB

SSF

SETUP 12341ISUP

Initial DP 1234

CO

NN

ECT 01654 456789

2

3

4

Mobile Originated (MO)

I wouldlike VPN

OK

Info sent to HLR toprovision CSI data for

VPN for this subscriber

User profilefor VPN entered

into SCF

CSI in Location Update

HLRgsmSCF

VPN is VirtualPrivate NetworkA

Administrator

User profilefor TDR entered

into SCF

MT CAMEL Call Setup - 1/2 Invocation of CAMEL - TDR Example

HLR

Mobile Terminated (MO)

gsmSCF

ISUP

4

SRI Ack

6

5

SendRouting

Info

GMSCB

SSF

VMSCA

VLRA

Initi

al DP

CONTINUE

8

7

HLR sends CAMELprofile in SRI Ack

to the GMSC

OKInfo sent to HLR toprovision CSI data for

TDR for this subscriber

I would like my callsto be directed to my mobile

every afternoon

TDR is TimeDependent Routing

B

VMSCB

VLRB

Administrator

MT CAMEL Call Setup - 2/2 End of Call Setup after use of CAMEL

HLR

Mobile Terminated (MO)

gsmSCF

ISUP

SRI Ack

PRN Ack

11

10Provide Roaming Number

Send RoutingInfo - suppression

of CAMEL

GMSCB

SSF

9

SETUP

14

12

13

Once CAMEL hasprovided the service,

Call Setup canproceed making surerouting information is

returned in the SRI

CONTINUE

8

B

VMSCB

VLRB

CAMEL OPERATIONS: SSF - SCF MESSAGE FLOWS - 1C/3

gsmSCF

RELEASE CALL

CONTINUE

CONNECT

INITIAL DP

gsmSSF

When a trigger is detected at a DP in the BCSM, Initial DP is sent to request instructions from the gsmSCF

To request the gsmSSF to perform the call processing actions, to route the call to a specific destination

gsmSCF tears down an existing call at any phase of the call for all parties involved in the call

To request the gsmSSF to proceed with the call processing at the DP at which it previously suspended the call processing to await gsmSCF

instructions. There is no change made to basic call

CAMEL OPERATIONS: SSF - SCF MESSAGE FLOWS - 2C/3

gsmSCF

ACTIVITY TEST

ACTIVITY TEST RESPONSE

gsmSSF

EVENT REPORT BCSM

REQUEST REPORT BCSM EVENT

Checks for the continued existence of a relationship between the SSF and SCF

Sent when a relationship still exists between the SSF and SCF

Requests the SSF to monitor for a call-related event (i.e dynamically arms EDPs)

Notifies the SCF of a call-related event (i.e an armed EDP is encountered)

CAMEL OPERATIONS: SCF - HLR MESSAGE FLOWS - 3C/3

HLR

ANY TIME INTERROGATION REQUEST

ANY INTERROGATION RESPONSE

gsmSCF

To request subscriber state and location from the HLR at any time

Provides the requested information to the gsmSCF

VLR

PROVIDE SUBSCRIBER INFO

PROVIDE SUBSCRIBER INFO ACK

To request subscriber state and location from the VLR at any time

Provides the requested information to the HLR

CAMEL interaction with GSM Call forwarding - 1D/4

• CAMEL treats the forwarding of a call in a similar way to a call origination, hence it is possible to trigger DP2 when a call is forwarded due to GSM Call Forwarding.

• If the subscriber is provisioned with O-CSI it is possible to invoke CAMEL as part of GSM Call Forwarding at both the GMSC and VMSC.

CAMEL and GSM Call Forwarding at the GMSC - 2D/4

T-CSI + O-CSI+ Forward-To-

Number (C address)

HLR

(1) ISUP

(2) SRI

GMSCB

SSF

SCFT-CSI

SCFO-CSI

(3) SRI-ACK

4) InitialDP(T-CSI

invoked)

5) Continue

7) InitialDP(O-CSI invoked)

8) Connect(CLI modified)

(Call is forwarded with modified CLI information)

The terminating service is activated first

The originating service can beapplied to the outgoing leg of the call forwarding.

GSM Call Forwarding invoked

9) ISUP

CAMEL and GSM Call Forwarding at the VMSC - 3D/4

1) ISUPVMSCB

SSF

SCFO-CSI

2) InitialDP(O-CSI

invoked)

3) Connect(CLI modified)

GSM Call Forwarding invoked

4) ISUP

The originating service can beapplied to the outgoing leg of the call forwarding.

(Call is forwarded with modified CLI information)

Applying O-CSI to a call forwarded by CAMEL (T-CSI) - 4D/4

T-CSI + O-CSI

HLR

(1) ISUP

(2) SRI

GMSCB

SSF

SCFT-CSI

SCFO-CSI

(3) SRI-ACK

4) InitialDP(T-CSI

invoked)

5) Connect (New Number (C)

+ O-CSI applicable)

7) InitialDP(O-CSI

invoked)

8) Connect(CLI modified)

(Call is forwarded with modified CLI information)

The terminating service forwardsthe call.

The originating service can beapplied to the outgoing leg of the call forwarding.

9) ISUP