Todd Wilson


Voice and telephony services have been viewed as constants for over the past hundred+ years. Picking up the telephone and hearing "dial tone" is something we don't think about, a simple thing in the life that households and organizations' all over the world take for granted. Over the past several decades, Private Branch Exchange (PBX) technology has proved its existence with great staying power. The phrase "five 9s" reliability has been a subject of many conversations pertaining to voice, and as time passes on, the PBX still gams more valuable trust and respect from its' users. It wasn't until approximately three to four years ago where the term "PBX" took on a new whole way of life. Traditional time-division multiplexing (TDM) technology was on the verge of being changed from one that provided digital capabilities, to one that provided full Internet Protocol (IP) integration into an existing data network. The TDM PBX was literally transformed overnight into an IP platform, causing a hundred years of technology and development to be readdressed and most likely looked upon as "legacy" technology moving forward. IP telephony technology is being looked at as the future of voice communications and as the integration of what used to be two separate worlds: voice and data. The overall architecture and feature parity with traditional PBX technology makes an easy selling point; however, it is the extra benefits and the overall reduction in costs that organizations' are seeing that makes this new technology so attractive. In general, IP telephony consists of transporting voice packets over a data infrastructure that supports the quality of service and resiliency that voice telephony demands. The underlying architecture is based upon IP technology and specific signaling standards that IP telephones and applications utilize to make IP telephony possible. As a result of the discussion aforementioned, the aim and direction of this thesis is built upon technical information, specifically regarding architecture, applications, protocols and the overall underlying principles of IP telephony. It is not intended as a sales pitch, rather intended to show the many advantages of IP telephony and how it is positioned as another IP-based solution into your existing data network. The following sections will be discussed: System Architecture Protocols Quality of Service Securing IP Telephony Cisco Infrastructure Components IP Telephony Case Study

Library of Congress Subject Headings

Internet telephony; TCP/IP (Computer network protocol); Telephone systems; Mobile communication systems

Publication Date


Document Type


Department, Program, or Center

Information Sciences and Technologies (GCCIS)


Perez-Hardy, Sylvia

Advisor/Committee Member

Troell, Luther


Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: TK5105.8865 .W567 2003


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