SBC – Access front end node. It deals with access policies and media handling
CSCF – Signalling switching in IMS Core Nw. Does not handle media
HSS – Owner of registration data and triggers
ENUM – translator for E164 to IP
CPE – Access Router in customer’s premise
MGCF – Access Gateway for PLMN (MSS) handling signalling
MGW – Gateway for PLMN handling Media
MRF – IMS IVR for announcements and media bridging
TFTP – Device Configuration Manager
NPS – Network Presence Server
OLO – Other Licensed Operator
SCF -Service Control Function
SIM – Service Interaction Manager
SIP – Session Initiation Protocol
SMPP – Short Message Peer to Peer Protocol
SMSC – Short Message Service Centre
SPA – Service Package Application
SRF – Specialized Resource Function
SSF – Service Switching Function