Although there are many similarities between 3G, 2.5G and 2G wireless networks (and many components are shared or connected through interoperable functions), there are also many differences between them.

The following table compares the essential protocol stacks involved in the core network, the radio access portion, and other areas of the three network categories.

Feature 3G 2.5G 2G
Core Network 3G MSC/VLR (with added interworking and transcoding), GMSC, HLR/AuC/EIR, 3G-SGSN, GGSN, CGF GMM/SM,MM,CM,BSSAP, RANAP,GTP,SCCP, MTP3B, M3UA, SCTP, Q.2630.1 (NNI), TCAP, MAP, ISUP, MTP3, MTP2, MTP1, Q.2140, SSCOP ATM, IP transport MSC/VLR, GMSC, SGSN, GGSN, HLR/AuC/EIR, CGF GMM/SM/SMS, MM, CM, GTP, SNDCP,NS, FR, LLC, BSSGP, BSSAP, BSSAP+, SCCP, TCAP, MAP, ISUP, MTP3, MTP2, MTP1 TDM, Frame Relay transport MSC/VLR, GMSC, HLR/AuC/EIR MM, CM, BSSAP, SCCP, ISUP,TCAP, MAP, MTP3, MTP2, MTP1 TDM transport
Radio Access Node B, RNC, MS W-CDMA, CDMA2000, IWC-136 GMM/SM, MAC, RLC, PDCP,RRC,Q.2630.1(UNI+ NNI),NBAP, RNSAP, RANAP, SCCP, MTP3B, M3UA, SCTP, GTP-U, Q.2140, Q.2130, SSCOP, CIP BTS, BSC, MS TDMA, CDMA, EDGE MAC, RLC, GMM/SM/SMS, LLC, SNDCP, BSSGP, NS, FR,RR, BSSAP, SCCP, MTP3, MTP2, MTP1 BTS, BSC, MS FDMA, TDMA, CDMA MM, CM, RR, LAPDm, LAPD, BSSAP, SCCP, MTP3, MTP2, MTP1
Handsets New type of terminal Multiple modes Voice, data and video terminals WAP, multimedia management New type of terminal Dual mode TDMA and CDMA Voice and data terminals WAP, no multimedia support Voice only terminals
Databases Enhanced HLR, VLR, EIR, AuC HLR, VLR, EIR, AuC HLR, VLR, EIR, AuC
Data Rates Up to 2Mbps Up to 57.6 Kbps (HSCSD) Up to 115Kbps (GPRS) Up to 384 Kbps (EDGE) Up to 9.6 Kbps
Applications Internet, multimedia SMS, Internet Advanced voice, Short Message Service (SMS)
Roaming Global Restricted, not global Restricted, not global
Compatibility Compatible to 2G, 2G+ and Bluetooth Not compatible to 3G Not compatible to 3G