Internet protocol based telephone system in which telephone traffic is transmitted at least in part over an Internet protocol based network retaining terminal telephones and exchanges

摘要

Subscribers (10,20) are respectively connected to access nodes (11,21) connected to a computer or Internet protocol (IP) based packet switching network (30), I.e. the Internet, while telephony servers (40,50) control establishment of calls to and from the subscribers. A telephony number server (60) is a database containing lookup tables for converting a telephone number identifying a subscriber into an IP address or address of the telephone server. Signaling between the subscribers and exchanges is carried out using a V5.1 protocol for public switched telephone networks and integrated services digital network (ISDN) base rate interface for ISDN primary rate interfaces. The standard user to network protocol is overlaid on an IP based network protocol. Independent claims are included for a method of establishing telephone calls between subscribers, for telecommunication means, for an access link and for a telephone exchange.