Signalling in GSM networks

Application protocols

Protocol Stack of SS7

MTP - Message Transfer PartSCCP - Signalling Connection Control Part

UP - User Part AP - Application Part

CAPCAP INAPINAPMAPMAP ISUP ISUP

TCAPTCAP

SCCP SCCP

TUPTUP

MTP level 3 MTP level 3

MTP level 2 (link-layer protocol)MTP level 2 (link-layer protocol)

MTP level 1 (64 kbit/s PCM time slot)MTP level 1 (64 kbit/s PCM time slot)

routing

Protocol Stack of MTP and TUP/ISUP/NUP

Protocol Stack Functions

SS7 protocols in various network elements