Note: Many topics at this site are reduced versions of the text in "The Encyclopedia of Networking and Telecommunications." Search results will not be as extensive as a search of the book's CD-ROM.

OSP is a client/server protocol that Internet service providers use to exchange authorization, accounting, and usage information to support IP telephony. OSP is defined by ETSI (European Telecommunications Standards Institute) Project TIPHON (Telecommunications and Internet Protocol Harmonization Over Networks).

OSP provides a way for ISPs to support billing for voice and fax over IP services. According to 3Com, a vendor of OSP equipment, an OSP clearinghouse can perform call authorization, and routing and rating functions among multiple service providers and interdomain networks, and provide usage reporting through call detail records for interservice provider billing. The protocol is implemented in voice telephony gateways such as softswitches, H.323 multimedia conferencing gateways, and SIP (Session Initiation Protocol) proxies.

Settlements are based on per-minute charges like the existing PSTN. With settlements in place, IP telephony can expand beyond the confines of single service providers or confederations of service providers into a global service.

Copyright (c) 2001 Tom Sheldon and Big Sur Multimedia.
All rights reserved under Pan American and International copyright conventions.