MESSAGE Transfer PART level 3 (MTP3) is the NETWORK layer inthe SS7 protocol stack. It routes SS7 signalling messages topublic network nodes by means of Destination Point Codes,and to the appropriate signalling entity within a NODE bymeans of a Service Info Octet. MTP3 is specified as part of the SS7 protocol and is also referred to as part of theB-ICI interface for ATM. MTP3 sits between MTP2 and the userparts (ISUP, TUP, SCCP and TCAP) of the SS7 protocol stack.B-ISUP is an Application Layer protocol run over MTP3.

Message Transfer Part level 3 (MTP3) is the network layer inthe SS7 protocol stack. It routes SS7 signalling messages topublic network nodes by means of Destination Point Codes,and to the appropriate signalling entity within a node bymeans of a Service Info Octet. MTP3 is specified as part of the SS7 protocol and is also referred to as part of theB-ICI interface for ATM. MTP3 sits between MTP2 and the userparts (ISUP, TUP, SCCP and TCAP) of the SS7 protocol stack.B-ISUP is an Application Layer protocol run over MTP3.