Internet Telephony Services for Presence With SIP and Extended CPL

Dongmei Jiang

Thesis submitted to the
Faculty of Graduate and Postdoctoral Studies
in partial fulfillment of
the requirements for the degree of

Master of Computer Science

Under the auspices of the
Ottawa-Carleton Institute for Computer Science

University of Ottawa
Ottawa, Ontario, Canada
December 2003

(C) Dongmei Jiang, Ottawa, Canada, 2003

Abstract


Internet Telephony is the next generation of telephony with many new
features and low cost. Because of the explosion of new features, it has
become critical to control and manage these features. The main challenge
in Internet Telephony is service programming. The Call Processing
Language (CPL) is a solution for end users to describe and control their
services in Internet Telephony. Current CPL focuses on call processing
services only. It is not adequate for the definition of many types of
new services, such as the combination of telephony services with email,
instant messaging, presence etc. This thesis extends CPL to describe
new Internet Telephony services including presence services and call
processing services related to presence. In the thesis, the presence
system is systematically described in a three-layer architecture. End
user's presence services and system basic services are clearly separated
in the architecture. Presence information, as the basis of presence
services, is extended from traditional "online" and "offline" indicators
to include broader meaning, such as location, phone line status, role and
availability status etc. Through CPL extensions for presence, user's new
presence services and new presence related call processing services are
illustrated by using various examples. A simulation system is implemented
to demonstrate the Internet Telephony services specified in extended
CPL. End users can create and modify their own services via the Graphic
User Interfaces (GUIs) and access their services at any location through
the Internet. The simulation system is verified with various test cases.

Keywords: Feature, Service, Policy, Internet Telephony, Presence, SIP,
CPL, PIDF