This presentation gives basic information on CAP

7/28/2019 This presentation gives basic information on CAP

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CAP

Slide 1

Deepak D


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Growth within the communications industry has

lead to the development of new platform forproviding space for additional services This platform is called Intelligent Network (IN) and using

this platform, new additional services can be addedwithout any additional cost of developing software (or)hardware for the existing network elements.

IN is a technique to make digital telecommunicationnetworks more effective using some principles by takingcontrol over CS calls to higher-layer control platform.

Principle behind IN is to take control over call by interceptingthe established call at a designated node in the network.

Switching Control Point is the control platform

IN Protocol will enable the operator to take control over thecall and execute the IN service logic in the control platform

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IN services are additional services which add tonetwork value, but are not provided by switchingnetworks.

Different IN standards have defined IN protocols.Popular IN protocols are : INAP (Intelligent Network Application Protocol)

CAMEL (Customized Applications in Mobile NetworksEnhanced Logic)

First service added using IN platform was

freephone (or) shared-cost numbers. Charging other party instead of calling party

Commonly used IN service in mobile network isPrepaidService.

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Intelligent Network Application Protocol (INAP)

Popular in 1990s and was dominant IN protocol

Mainly used in the fixed network environment

Had lot of issues due to clarity in specification

Deployments were vendor and operator specific : Vendorhas to specify encoding of parameters (mostly octetstrings)

Mobility management was not supported

Customized Application for Mobile networks

Enhanced Logic (CAMEL) This protocol is introduced to resolve the mobility

management issue.

CAMEL is a child of INAP with ability to provide INservices for wireless networks also

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Slide 5

SCP

(SCF)

Execute IN

Service

SSP

(SSF)

INAP

IN PROTOCOL

CALLING PARTY CALLED PARTY

SIGNALING SIGNALING

EXTERNALNETWORK

SIGNALING

HLR(SCF)

CA

P

SIGNALING

CAMEL IN

PROTOCOL

Execute IN

Service

FIXED NETWORK

MOBILE NETWORK


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Service Switching Function (SSF)

This functionality resides in SSP Handles IN Protocol to pass call control to SCP and expects

acknowledgment back.

When a call is established, if IN service is required, SSF shallcopy the signal information and then exchanges with SCP to

take necessary action Eg: In GSM network, each MSC can be equipped with an SSF (or)

only designated MSCs may be equipped with an SSF and it will runCAMEL IN protocol to exchanges message with SCP

Service Control Function (SCF)

This functionality resides in SCP Facilitates execution of IN services with the help of IN

protocol & SSP

IN service logic implemented on SCP is operator-specific

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Required for triggering IN service

Dialogue between SSF & SCF should exists for

any IN service to get executed

Dialogue between SSF & SCF will be governed bya process

Dialogue between SSF & SCF is called IN Dialogue

IN Dialogue facilitates the exchange of

instructions & notifications between SSF & SCF Instructions (or) notifications exchanged

between SSF & SCF through IN dialogue is packed

with in transaction capability messages (TCAP)

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It is developed as a standard for mobile intelligenceacross different vendor equipment for mobile networks. End user should be able to roam between different networks

(may be in different countries) and be reachable at the samenumber and should receive only one bill from the originalservice provider (Home Operator)

For operators, CAMEL has become prime method for

putting the intelligence into any networks especiallymobile networks such as GSM, GPRS, UMTS.

Main principle behind CAMEL is to act as a IN prototypeusing which many services can be enabled inwired/wireless networks.

CAMEL interacts mainly with Network SwitchingSubsystem (Core Network MSC, HLR) of mobilenetworks.

NOTE : CAMEL is not a service but it is a feature to create services.

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Natural evolution of the IN standards : ITU-T & ETSI

Need for CAMEL grew during the development of GSMN/W Std.

During the deployment of GSM in early 1990s, IN wasused only for fixed networks such as PSTN & ISDN

Development of CAMEL standard started in 1996 to meetthe demand of advanced IN services

Development happened in 4 phases from PHASE 1 toPHASE 4

CAMEL entities [GSM & GPRS network]

gsmSCF: GSM Service Control Function

gsmSSF: GSM Service Switching Function

gsmSRF: GSM Specialized Resource Function

gprsSSF: GPRS Service Switching Function

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Two types of CAMEL IN services Basic CAMEL IN Services Subscribers do not have to have a subscription

Universal Access Numbers

Premium Rate Calls Freephone Numbers

Voting Services (or) Competitions

Subscribed CAMEL IN Services Services that are assigned to a subscriber.

Virtual Private Network

Prepaid Subscribers

Family & Friends

Mobile Access Hunting

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CAP is

CAMEL Application Protocol Protocol used to implementCAMEL functions in the GSM system

Signaling protocol used in the Intelligent Network (IN)

Layered on top of the TCAP (Transaction CapabilityApplication Part) of the SS7 protocol suite and is CAMEL

counterpart of INAP protocol ROSE (Remote Operations Service Element) user protocol

Means of adding intelligent applications to mobile networks

Based on a subset of ETSI Core and allows for theimplementation of carrier-grade, VAS (Value Added Services)

such as : Messaging

Prepaid

Fraud Control

Freephone in both GSM & GPRS networks.

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CAP is the CAMEL protocol mainly used between gsmSSF

and gsmSCF gsmSSF will be resided in MSC in a GSM network and gsmSCF

In GPRS network, CAP operations are performed betweengprsSSF(SGSN) and gsmSCF using Ge interface

Capability of CAP is defined by operations

An operation is mechanism for one entity to start a procedurein the peer entity

E.g.: gsmSSF in a MSC will invoke a CAMEL service on SCP bysending IDP Initial DP operation

Transfer of CAP operations between gsmSSF (MSC) andgsmSCF (HLR, VLR) is done through Signaling System(SS7)

Subsystem Number (SSN) for CAP is 146 and the entity isMSC

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MTP - 1

MTP - 3

MTP - 2

ISUP

INAP

TCAP

CAP

MAP

SCCP


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VMSC(gsmSSF)

HLR

gsmSCFHPLMN

IPLMN

GMSC(gsmSSF)

VPLMN

ENTITY DESCRIPTION

HPLMN GSM network that a GSM user is a subscriber of.

VPLMN GSM network where a subscriber is currently registered.

IPLMN It is a PLMN containing GMSC that handles Mobile Terminating (MT)calls.

VMSC Visiting MSC

GMSC Gateway MSC Entity controlling MT calls

HLR Database containing subscription record for each subscriber of the

network


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SGSN

(gsmSSF)

HLR

gsmSCF

HPLMN

IPLMNVPLMN

ENTITY DESCRIPTION

SGSN Serving GPRS Support Node

GGSN Gateway GPRS Support Node


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gsmSCF

SGSN

gprsSSF

GPRS DIALOGUE

HANDLER

CAP

CAP

VMSC

gsmSSF

gsmSCF

GSM DIALOGUE

HANDLER

CAP

CAP

GSM

NETWORKGPRS

NETWORK


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MSC

(SSF)

SCP

(SCF)

PSTN

Incoming Call

IDP

IAM

ANC

ACM

ACH

Charging the calling

party after

analyzinginformation

CUE

ACR

RC

Release Call

REL

RLC


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Specification

3GPP Specification 23.078 (Release 11) - CS

3GPP Specification 29.078 (Release 11) - IMS

Books

CAMEL : Intelligent Networks for the GSM, GPRS

& UMTS Network

Rogier Noldus

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This presentation gives basic information on CAP

Documents

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