* Mobile Subscriber ISDN Number (MSISDN)
--> is a number uniquely identifying a subscription in a mobile network.
--> it is the telephone number of the SIM card in a mobile/cellular phone.
--> it is Mapped to the Mobile Station Roaming Number (MSRN) by HLR.
* International Mobile Subscriber Identify (IMSI)
--> is a unique number associated with all mobile phone users.
--> Stored in SIM/HLR
* Temporary Mobile Subscriber Identity (TMSI)
--> is randomly assigned by the VLR to every mobile in the area, the moment it is switched on.
--> is local to a location area
--> is assigned by VLR and stored in VLR
* International Mobile Equipment Identity (IMEI)
--> Unique ID to handset, used by air interface
2. Encoding
* MSISDN = CC + NDC + SN
--> MSISDN: Mobile Station ISDN Number
--> CC: Country Code
--> NDC: National Destination Code
--> SN: Subscriber Number
* IMSI = MCC + MNC + MSIN
--> IMSI: International Mobile Subscriber Identity
--> MCC: Mobile Country Code
--> MNC: Mobile Network Code
--> MSIN: Mobile Station Identification Number
* MSRN = CC + NDC + SN
--> MSRN: Mobile Station Roaming Number
--> CC: Country Code
--> NDC: National Destination Code
--> SN: Subscriber Number
* LAI = MCC + MNC + LAC
--> MCC: Mobile Country Code
--> MNC: Mobile Network Code
--> LAC: Location Area Code
* IMEI = TAC + FAC + SNR + spare
--> IMEI: Internal Mobile Equipment Identity
--> TAC: Type Approval Code
--> FAC: Final Assembly Code
--> SNR: Serial Number
* IMEISV = TAC + FAC + SNR + SVN
--> IMEISV: International Mobile Equipment Identity and Software Version Number
--> SVN: Software Version Number
* CGI = MCC + MNC + LAC + CI
--> CGI: Cell Global Identity
--> CI: Cell Identity
--> BSIC: = NCC + BCC
--> BSIC: Base Station Identity Code
--> NCC: Network Color Code (3bits)
--> BCC: Base Station Color Code (3bits)
* LN = CC + NCD + LSP
--> LN: Location Number
--> CC: Country Code
--> NCD: National Destination Code
--> LSP: Locally Significant Part
* RSZI = CC + NDC + ZC
--> RSZI: Regional Subscription Zone Identity
--> CC: Country Code
--> NDC: National Destination Code
--> ZC: length of the Zone code (2 octets)
3. Usage
* Information resident in MS & SIM
--> IMSI
--> TMSI
--> IMEI
--> misc. information
* Routing Information used by Network
--> MSISDN
--> MSRN
4. Numbering and Routing
