3. BSS (Base Station Subsystem)
- For 2G includes BTS (Base Transceiver Station) and BSC (Base Station
Controller)
- For 3G includes NodeB and RNC (Radio Network Controller)
- Provides radio coverage to prescribed geographical areas, known as
the cells. It contains equipment required to communicate with the MS.
4. NSS or Core Network
- Includes MSC, SGSN, GGSN, HLR, EIR, AuC
- Carries out call switching, packet switching and mobility management
functions
5. Mobile Station
Consists of Mobile Equipment and SIM
• IMEI (15 digits)
• IMSI
• MSISDN
• Authentication Key (Ki) (128 bits)
• SMS messages and contacts
• Other parameters updated by the
network
6. Home Location Register (HLR)
- A database that stores large number of subscriber
information including IMSI, MSISDN, current subscriber
location, subscriber barrings, static IP, QoS, etc.
Equipment Identity Register (EIR)
- keeps a list of mobile phones which are to be banned from the
network
7. Serving GPRS Support Node (SGSN)
- Mobility management functions (attach, detach, routing
area update)
- store and maintain subscriber information in the SGSN
location register
- session management functions (PDP context
activation/deactivation)
8. Gateway GPRS Support Node (GGSN)
- Gateway between the GPRS mobile and external packet data networks
- Packet handling functions (forwarding incoming user data from a SGSN
to a Gi interface and vice versa)
- session management functions
- User administration (e.g. IP address and DNS address assignment for
the registered MS)
9. GPRS Mobility Management
functionalities
• PDP Context Activation and Deactivation
Session Management functionalities
• GPRS attach and detach
• Security
• Routing Area Update
19. What is PDP Context?
• It is a data structure present on both the SGSN and the GGSN which
contains the subscriber's session information when the subscriber has
an active session.
• When a mobile wants to use GPRS, it must first attach and then
activate a PDP context.
