Signaling System No. 7 (SS7/C7): Protocol, Architecture, and Services

Appendix J. ITU and ANSI Protocol Comparison

This appendix highlights some of the key differences between the ITU-T C7 and ANSI SS7 protocols.

ITU-T protocols are used on the international plane; every country that wishes to connect to the International C7 network worldwide strictly adheres to these protocols. The comparison presented here is between the North American ANSI protocols (national plane) and the ITU-T recommendations that are to be adapted for use on the national plane. Apart from North America, China and Japan made some modifications outside of the ITU national recommendation framework; however, we do not discuss these here.

Message Transfer Part 3

ANSI [1] uses 24-bit Point Codes (PCs) for addressing, while ITU [52] uses 14 bits. This ...