Interfaces and Protocol in GPRS Network

Interfaces : 

Gn : Interface between SGSN and GGSN
Gp :  Interface between SGSN and GGSN in visitor PLMN
Gr : Interface between SGSN and HLR
Gs : Interface between SGSN and MSC

Gb : Interface between SGSN and BSS
Gd : Interface between SGSN and SMS-GMSC/SGSN
Gi : Interface between GGSN and PDN
Gf : Interface between SGSN and EIR

Procotols :

DTAP : Direct Transfer Application Part exist between MS and MSC

LLC: Logical Lnk Control creates as secure and reliable link between MS and SGSN

BSSGP : Base Station System GPRS protocol transfers control,signaling and user data information between BSS and SGSN

SNDCP :  LLC containes SNDCP(Subnetwork Dependent Convergence Procotol) message exist between MS and SGSN which performs segmentation,multiplexing and reassembly

MAP: Mobile Application Part  is an SS7 Procotol used by multiple nodes such as HLR,VLR,MSC,EIR,AUC,SMSC,SGSN

TCAP: Transaction Capabilities Application Part is used by GPRS network node to exchange MAP data

GTP : GPRS Tunneling is based on IP network used by SGSN,GGSN to transfer control and data message over Gn interface

BSSAP : Base Station Subsystem Application Part or BSSAP+(support for GPRS procedure) is used to transfer message between MSC/VLR and SGSN over Gs interface.