Handovers & Security in GSM

Handovers:

Between 1 and 2 – Inter BTS / Intra BSC.

Between 1 and 3 – Inter BSC/ Intra MSC.

Between 1 and 4 – Inter MSC

Security in GSM:

On air interface, GSM uses encryption and TMSI instead of IMSI.

SIM is provided 4-8 digit PIN to validate the ownership of SIM.3 algorithms are specified :

- A3 algorithm for authentication
- A5 algorithm for encryption
- A8 algorithm for key generation