Distributed calling system

Abstract

Telephone service is supplied using a distributed architecture that employs a collection of resources each of which exposes a hierarchical namespace. The architecture includes two fundamental resource types, the device server and the call coordinator, which are interconnected by a network employing a common protocol, eg., TCP / IP. The interaction between the various resources follows "client-server" principles to implement end-to-end communication. Device servers represent physical / logical telephone devices, which include a) end-point device servers and b) gateway device servers. End-point device servers 1) represent controls for communication, such as keypads, indicator lamps, and displays, and 2) perform media rendering, e.g., voice digitization, transport, and reconstruction. Gateway device servers have two "sides". One side is implemented to appear to a call coordinator as if it were a device server, and the other side has an interface adapted to interwork with a preexisting island of telephone service. In the term "device server", "server is used in the conventional manner of the "client-server" architecture, where the server serves request from the clients and does not take action unless it is in response to a client request. A call coordinator functions in the role of the "client". The device servers are unaware of communication state, which is maintained by the call coordinator and exposed as a hierarchical namespace. The call coordinator treats the processing of a call as a sequence of steps each of which can be implemented by a small piece of computer executable code called a "feature applet".

Description

technical field [0001] The present invention relates to providing communication services using a distributed call system. Background technique [0002] A well-known problem in the telephone industry is that the systems that provide telephone service, such as central offices (COs), private branch exchanges (PBXs), and Internet telephony servers, are functionally separate islands, each of which has its own own specific syntax and semantics. In addition, each larger island has its own sub-islands, which likewise adopt their own syntax and semantics. For example, the CO employs a) Signaling System 7 (SS7), b) Integrated Services Digital Network Primary or Basic Rate (ISDN-PRI / BRI), c) T1 flashing / starting, d) analog loop starting, and e) analog Ground starts; while internet telephony has a) H.323 and b) Session Invitation Protocol (SIP). Using different syntax and semantics makes it difficult to interconnect the various islands, and it is practically impossible to provide fea...

AI Technical Summary

Problems solved by technology

Using different syntax and semantics makes it difficult to interconnect the islands, and it is practically impossible to provide features where the islands work seamlessly together

Images