Customized Applications for Mobile Network Enhanced Logic CAMEL
Customized Applications for Mobile Network Enhanced Logic (CAMEL) Zhaohui Deng Yinyan Zhou 1
What Is CAMEL n n n CAMEL is the wireless intelligent network standard for GSM networks CAMEL is not a separate service but a new feature ( It is a tool to help the network operator to provide the subscribers with OSS even when roaming outside the HPLMN) In North America the corresponding standard is WIN and CAMEL use almost the same Intelligent Network Conceptual Model OSS: Operator Specific Services HPLMN: Home Public Land Mobile Network 2
Evolution of Wireless Intelligent Network n n Switchboard: Operator manually intervene with an intelligent routing decision Automatic Switching: hard-wired service logic, dependent on switching vendor for all aspects of service logic necessary to deploy new features, equipment from different vendors made it hard for ubiquitous service deployment 3
Evolution of Wireless Intelligent Network (Cnt) n n Stored Program Control: programmable service logic, but not modular. New service introduction is hard due to dependency between service and service specific logic associated with that service. Service logic used for one service could not be used for another Common Channel Signaling: mid-1970 s. Out-band signaling vs. in-band signaling path 4
Evolution of Wireless Intelligent Network (Cnt) n n Advanced Intelligent Network: provide serviceindependent service logic and service management, facilitate independent service development capability WIN and CAMEL: standardized capabilities in conjunction with SS 7 signaling, provide network intelligence efficiently and seamlessly in wireless networks 5
Driver for CAMEL Emerging n n Prior to CAMEL, GSM has INAP as protocol injecting intelligence into GSM network. INAP designed for wireline networks, no mobility management. CAMEL: standard to provide wireless intelligent network capabilities for development, deployment and operation of enhanced mobile communications service and roaming across different vendor switches 6
WIN BCSM DP Example n n Originating BCSM detection Points: n Origination_attempt_Authorized DP – A point in the call ( such as an authorized customers initiates a call) when an external element is queried prior to the calling party dialing digits. Can be used for service such as voice activated dialing. n Analyzed_Information DP: for Incoming call screening at customer’s home MSC? ? n Collected_information DP: used for providing service to calling party such as Call forwarding BCSM: basic call state model 7
WIN BCSM DP Example n Terminating BCSM Detection Points: n n Facility_Selected-and_Available DP: calling name service to customer T_Busy and T_No_Answer DP: for routing call to a voice message system or special announcements/tones 8
Service Drivers for WIN Phase I n n Calling Name Presentation (CNAP) Voice Controlled Service (VCS) n n n Such as basic voice controlled dialing VCS with voice authentication, speech –to-text conversion, etc Incoming Call Screening (ICS) n Answer, don’t answer, redirect 9
Service Drivers for WIN Phase II n Prepaid Charging(PPC) n n n Preferred Language Support Free Phone n n Launch Analyzed. Information message to SCP, seize IP to set up Connection. Resource message to MSC to connect to IP and IP play announcement to direct how to make the call, completely toll free and mobile airtime free Billing Service Capabilities n n Should be invoked before any other service to verify the balance Advice of charging; inform cost of impending call Call management service n Rejection of undesired annoying call 10
Example of WIN phase II Free Phone Serving System IP SCP MSC MS origination ANLYZD[TRIGTYPE, DGTSDIAL, TRANSCAP, WINCAP] SEIZED[SRFCapability, PLIND] Seizes[TLDN] CONNRES[DSTDGT, CARDGTS, ROUTDGTS] TLDNAT call setup MSC upon recognizing a Free. Phone call attempt, launched a Analyzed Information(ANLYZD) message to SCP. The SCP getting the request, seizes the IP resource and IP send Connect Resource(CONNRES) message to the MSC, directing it to set up a connection to IP. IP plays an announcement to the caller(relative to the Free. Phone number called)Upon listening to the announcement, a a series of release messages are played prior to the MSC setting the call up to the appropriate telephone number associated with Free. Phone number. INSTREQ[ ] SRFDIR[ANNLIST PLAY ANNOUNCEMENT srfdir[] anlyzd[TERMLIST, DMH_SVCIDLIST, BILLDGTS] instreq[ ] Release message Call setup 11
Service Drivers for WIN Phase III n Location-Based Service 12
Phased Development of Standards – CAMEL Phase I n n Introduce basic INAP capabilities such as support of initial DP message Basic call set-up reporting capabilities: inform CSE of mobile origination and termination status, call-related CSE interactions Suppress announcement tones at the serving system during call termination, allowing the home system to play announcements in native language of the home system Offer Any Time Interrogation (ATI) message, a GSM MAP message: interrogate HLR to derive info about specific customer’s location and status CSE: CAMEL Service Environment MAP: Mobile Application Part, protocol that interconnects wireless telephone system 13
Example of CAMEL phase I MS Originating CAMEL call MS MSC/VLR + gms. SSF A C gsm. SCF PSTN CAP-initial. DP CAP-Connect B ISUP-IAM A: MSC gets CAEML service info from VLR during the call setup of a MS, gms. SSF in the visiting network send the Initial. DP message to gsm. SCF and suspend the call processing. The Initial. DP message contains service key, called and calling party number, calling party’s Category, location number, bearer capability, event type BCSM, location and IMSI. After the service logic processing, B gsm. SCF can for example do number translation, a CAMEL-specific Service logic is initiated from gsm. SCF C MSC uses the information received to set up a call 14
Phased Development of Standards – CAMEL Phase II n n n Most significant enhancement over phase I is to support SRF, would allow user interaction with a VRU within CSE Provide additional GSM MAP related improvements including support of USSD, another user interaction capability enhancement, this call-unrelated CSE interaction capability allows the subscriber to invoke CAMEL-based service via USSD commands. Online charge indication via the Advice of Charge( Ao. C) feature for mobile originated calls. Ao. C is call-related CSE interaction that can be very useful when deployed in conjunction with services such as a Free Phone, prepaid and premium calling services. SRF: Specialized Resource Function VRU: Voice Response Unit USSD: Unstructured Supplementary Service Data 15
CAMEL Phase I Architecture Home Network HLR MAP gsm. SCF MAP CAP gsm. SSF GMSC Interrogating Network VLR Roaming leg gsm. SSF VMSC Visiting Network Dotted lines for signaling connection, continuous line present a voice connection MAP: Mobile Application Part GMSC: gateway MSC CAP: CAMEL Application Protocol VMSC: visiting MSC 16
CAMEL Phase I Architecture Home Network n present home PLMN (public land mobile network) of CAMEL subscriber n Home Location Register (HLR) and GSM Service Control Function are the network elements involved in CAMEL n HLR stores for subscriber requiring CAMEL support information regarding O-CSI, TIF-CSI, U-CSI and SS-CSI n O-CSI, SS-CSI are sent to VLR in case of location update or O-CSI, SS-CSI update U-CSI: USSD-CSI SS-CSI: Supplementary Service_CSI 17
CAMEL Phase I Architecture Home Network n n n O/T-CSI is sent to GMSC when HLR responds to a request for routing information TIF-CSI, U-CSI and UG-CSI are stored in HLR only. HLR may provide an interface towards gsm. SCF for Any Time Interrogation SS-CSI: Supplementary Service – CSI TIF-CSI: translation information flag – CSI, subscriber data indicate that when subscriber register a forward-to number, that HLR shall not attempt to perform any translation, number format check, (Forward To Number) FTN check, call barring check 18
CAMEL Phase I Architecture n Interrogating Network n Perform the interrogation of the home network for information on treatment of terminating CAMEL calls n Calling party of the terminating CAMEL call resides in the interrogating network and the called party resides in the visiting network. n Gateway MSC (GMSC) and gsm. SSF are the entities handling of terminating CAMEL calls n When processing the calls for subscriber requiring CAMEL support, GMSC receive O/T-CSI from HLR. If TCSI exists, indicating GMSC to request instructions from gsm. SSF for further execution 19
CAMEL Phase I Architecture n Visiting Network n It is PLMN where the CAMEL subscriber is roaming. n Involve handling of originating and forwarded CAMEL calls n May request for location information and status of the subscriber n Set up calls from and towards the visiting subscriber, while handling the originating calls, VMSC detects if OCSI exists, if does, then initial contact to gsm. SCF take place n When roaming to a visiting network which doesn’t support CAMEL, home network handle the roaming 20
Relationship n n n HLR-VLR interface: send CAMEL related subscriber data to VPLMN and provision of Mobile Station Roaming Number (MRSN), retrieve subscriber status and location, or to suppression of announcement for CAMEL service GMSC-HLR interface: used at terminating calls to exchange routing information, subscriber status and location, suppression of announcement GMSC-gsm. SSF interface: internal interface, make it easy for handling DPs 21
Relationship n n gsm. SSF-gsm. SCF interface: used for gsm. SCF to send instruction to gsm. SSF to play tones. announcements to the users. gsm. SCF-HLR interface: used by gsm. SCF to request information from HLR 22
CAMEL Phase I: Originating Basic Call State Model O-Null&Authorize_Origination _Attempt_Collect-Info DP 2 O_Exception Collect_Info Analyze, Routing & Alerting DP 7 DP 9 O-Disconnect O_Answer O_Active 23
Description of O-BCSM DPs in the MSC Note: BLUE for phase I BLACK is added In phase II 24
Originating Call Example, Phase I gsm. SCF MSC DP 2 encountered (Initial. DP) Monitor DP 7 (N)(REquesr. Report. BCSMEvent) Monitor DP 9 (R)(REquesr. Report. BCSMEvent) Continue call processing (Continue) Check connection (Activity. Test) Answer to connection check(activity. Test Response) N: Notification R: request DP 7 encountered (Event. Report. BCSM) DP 9 encountered (Event. Report. BCSM) Continue call processing (Continue) 25
CAMEL Phase I: Terminating Basic Call State Model T_Exception T-Null DP 12 Terminating_Attempt_Authorized Terminating Call Handling DP 15 DP 17 T-Disconnect T_Answer T_Active 26
Description of T-BCSM DPs in the GMSC 27
CAMEL Phase II Architecture 28
CAMEL Phase II Architecture and Relationship n n Phase II is based on phase I architecture. The basic new component is the gsm. SRF. It provides a pool of resources for access by other network entities gsm. SCF –gsm. SRF interface: used by gsm. SCF to instruct the gsm. SRF to play tones/announcement to the users 29
CAMEL Phase II: Originating Basic Call State Model DP explanation Please refer to former slide 30
CAMEL Phase II: Terminating Basic Call State Model DP explanation Please refer to former slide 31
Terminating Call Example, Phase II gsm. SCF MSC DP 12 encountered (Initial. DP) Monitor DP 15 (N)(REquesr. Report. BCSMEvent) Monitor DP 17 (R)(REquesr. Report. BCSMEvent) Continue call processing (Continue) Check connection (Activity. Test) Answer to connection check(activity. Test Response) DP 15 encountered (Event. Report. BCSM) DP 17 encountered (Event. Report. BCSM) Continue call processing (Continue) 32
An example of Virtual Private Network in a visited network using CAMEL 33
An example of VPN in a visited network using CAMEL(Cnt) n 1. A subscriber who has a VPN service in his home network is "roaming" in a network abroad. To call a colleague at the home office, all he has to do is dialing the colleague's four-digit extension number “ 4772”. The exchange (SSP/MSC) in the visited network classifies the call as a "CSE event“. DP 2 is encountered, this Initial. DP message contains from VMSC to gsm. SCF contains service key and other subscription information. The set-up process is temporarily interrupted. VPN: Virtual private networks 34
An example of VPN in a visited network using CAMEL(Cnt) n 2. gsm. SCF in the home network ask VMSC to monitor the DP 7 and DP 9, then it translates the extension number into a Bnumber for international routing and transfers the information to the MSC in the visited network, which resumes the set-up process. 35
Reference n n n 3 GPP TS 03. 78: Customised Application for Mobile Network Enhanced Logic phase 2 3 GPP TS 02. 78: Service Definition Igor Faynberg, L. R. Gabuzda, T Jacobson, H. L Lu: The development of the Wireless Intelligent Network and its Relation to the international Intelligent Network Standards E. Geulen, J Hartmann: Open Service Provisioning in GSM – What do we gain with CAMEL J Hartmann: The Alignment of IN and GSM Gerry Christensen etc. Wireless Intelligent Network 36
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