MOC Call Flow

Number Normalization

Number Normalization

Camel Subscription Information (CSI)

CAMEL Subscription Information (CSI) is a part of the subscriber data that is stored in the HLR. The CSI indicates that the subscriber has CAMEL services.

The CSIs are:

O-CSI - Originating CAMEL Subscription Information (O-CSI) identifies the subscriber as having originating CAMEL services.

T-CSI - Terminating CAMEL Subscription Information (T-CSI) identifies the subscriber as having terminating CAMEL services.

SS-CSI - Terminating CAMEL Subscription Information (T-CSI) identifies the subscriber as having terminating CAMEL services.

TIF-SCI - The Translation Information Flag CAMEL Subscription Information (TIF-CSI) is located in the CAMEL subscriber data in the HLR. If the HLR receives a request from a CAMEL subscriber with the O-CSI to register a forwarded-to number and the TIF-CSI is not set, the HLR applies the usual procedure.

U-CSI - USSD CAMEL Subscription Information (U-CSI) identifies a set of subscriber-specific mappings from a USSD service code to a gsmSCF address.

UG-CSI - General USSD CAMEL Subscription Information (UG-CSI) identifies a set of mappings from a USSD service code to a gsmSCF address.

VT-CSI - General USSD CAMEL Subscription Information (UG-CSI) identifies a set of mappings from a USSD service code to a gsmSCF address.

D-CSI - The Dialed service CAMEL Subscription Information (D-CSI) identifies the subscriber as having home network operator dialed CAMEL services.

SMS-CSI - The Dialed service CAMEL Subscription Information (D-CSI) identifies the subscriber as having home network operator dialed CAMEL services.

M-CSI - The Mobility management event notification CAMEL Subscription Information (M-CSI) contains subscription information for subscribers that require CAMEL support of mobility management events.

GPRS-CSI – The GPRS Camel Subscription Information (GPRS-CSI) contains subscription information of the subscribers having the GPRS CAMEL service.

N-CSI - The Network-dialed service CAMEL Subscription Information (N-CSI) identifies the roaming network operator dialed CAMEL services.

CAP Phase1, Phase2, Phase3 and Phase4 Comparison

Wiki Page:

http://en.wikipedia.org/wiki/Customised_Applications_for_Mobile_networks_Enhanced_Logic

Network Hierarchy Concept: The OSI Reference Model

Application	Network service part of applications Provides network services to applications (e.g. protocols to applications such as snmp)
Presentation	Data presentation Presents data in the right format to the application layer (includes encryption, reformating, restructuring of data)
Session	Interapplication communication Maintains sessions between applications
Transport	End-to-end connection Ensures data transport reliability, information flow (includes maintaining of virtual circuits between hosts)
Network	Data delivery Provides routes between two host systems (might be at different locations) (includes network discovery and routing decision)
Data Link	Access to media Defines the data format and how the access to the media is controlled (includes bit-error correction)
Physical	Binary transmission on a physical link Electrical, mechanical, procedural, and functional specification

GSM Mobility Management

Mobility Management is one of the features of the GSM network that allows the mobile phones to make or receive calls while moving one place to another.

Mobile device uses the location update procedure to update the current location information to the cellular network. Mainly there are three different reasons for a mobile station to do a location update.

• Normal location update
• IMSI attach
• Periodic registration

Whenever a mobile station moves from one location to another or comes to an active state (IMSI attach), the mobile station will check the Location Aread Identity (LAI) stored in its SIM against the LAI of the cell. When both LAIs are different, mobile station will initiate a location update process. The network also has a provision for periodic registration to avoid the unnecessary paging of the mobile if MSC never receives the IMSI detach message.

Normal location update

Mobile station will initiate a normal loaction update procedure as when it finds a change of location area. As soon as a mobile station changes the location ares, it will compare the LAI stored in the SIM with the current LAI. If the two differs, then mobile station has to update the new location information to ensure that the mobile station will be paged to corret location.

The location update procedure will start with the mobile station sending the new location information to the network. After the authentication, the MSC will update its VLR. If the mobile station is new to this MSC, then MSC will interact with the HLR to get all the necessary information about the subscriber and then updates its VLR.

IMSI attach

When a mobile station switched on, ie, moved from an idle state to active state, it will try to attach to the network. This process of attachment is called IMSI attachment. During the IMSI atatch procedure, if the MSC finds that the mobile station is new, then MSC will query the corresponding HLR and then it will update the VLR with status “IMSI Attached”. During the process, the HLR will update its own data base and sends a message to the old MSC where the mobile station was located before to update its VLR.

Similarly, when a mobile station is switched off or sim card is removed, the mobile station will sends a message to the VLR and the VLR will mark the mobile station status as detached. Once the status is updated in the VLR, the incoming call to the mobile station will not be paged.

Periodic Registration

It is not necessary that the MSC will always gets the IMSI detach request from the mobile station whenever the later is switched off. So there will be a possibility of unnecessay paging of the mobile whenever there is an incoming call. The periodic registration is provisioned to avoid such unnecessay paging.

After each registration, the mobile station and MSC will reset their timers and when the timer in mobile station expires, the mobile station will perform a location update. If the mobile station does not perform a location update within the time, then the MSC will update the VLR and HLR with status a “detached”.

Standardization of CdPA

Different formats
Format	Numbers
National format	0 9443 124365
International format	91 9443 124365
Unknown format	0091 9443 124365 (Longest unknown format, a complete phone number up to 20 digits)