2G/3G PS Core Network Interfaces (GPRS/UMTS)
Hello.. You can find the full course through the following link,
https://mpc-courses.teachable.com/p/l...
or you can visit https://MobilePacketCore.com
Gb is the interface between the BSC and the SGSN.
Iu PS is the interface between the RNC and the SGSN.
Gn/Gp is the interface between the SGSN and the GGSN.
Gr is the interface between the SGSN and the HLR.
Gi is the interface between the GGSN and the PDN.