This is all about telecom core signalling. Core network signalling is used to make a call, SMS and data in 3G, 4G and LTE network. There are various protocols used for core network signalling.
This is the legacy protocol used for signalling for Voice and SMS. For Voice ISUP protocol is used for call setup and for SMS GSM MAP is used over SS7 or Sigtran. With the internet growth for speed and stability. The legacy SS7 protocol signalling is also used over IP network this is called Sigtran. The transport layer protocol SCTP is used for sigtran. In Sigtran there are adaptation layer are defined for the various user.
M3UA, this layer is defined for the MTP3 users in the SS7 protocol. The users of MTP3 are Isup and SCCP. With this layer SCCP and ISUP signalling can be done over SCTP/IP.
SS7 protocol
3G Data Core:
Nodes :
SGSN, HLR and GGSN
Protocols:
GSM-MAP, GTP
3G Voice Core:
Nodes:
MSC, HLR, GMSC and VLR
Protocols:
GSM-MAP, Codecs.
SMS Core :
Nodes:
SMSC, VLR, MSC
Protocols:
GSM-MAP
SS7 or Sigtran
M3UA, this layer is defined for the MTP3 users in the SS7 protocol. The users of MTP3 are Isup and SCCP. With this layer SCCP and ISUP signalling can be done over SCTP/IP.
SS7 protocol
3G Data Core:
Nodes :
SGSN, HLR and GGSN
Protocols:
GSM-MAP, GTP
3G Voice Core:
Nodes:
MSC, HLR, GMSC and VLR
Protocols:
GSM-MAP, Codecs.
SMS Core :
Nodes:
SMSC, VLR, MSC
Protocols:
GSM-MAP