The SPIRITS Architecture
Igor Faynberg, H. Lu, M. Weissman · 2001
This document describes the architecture for supporting SPIRITS services, which are those originating in the PSTN (Public Switched Telephone Network)and necessitating the interactions between the PSTN and the Internet. (Internet Call Waiting, Internet Caller-ID Delivery, and Internet Call Forwarding are examples of SPIRIT services.) Specifically, it defines the components constituting the architecture and the interfaces between the components.