Packet Guide to Voice over IP

Preface

A short while ago, as network engineers made plans for the future, one of the considerations was the eventuality of Voice over the Internet Protocol, or VoIP. For several years, VoIP was always “on the horizon” or “around the corner,” as many believed that it was coming but were unsure about the timing. The question was whether network designers and educational programs should become early adopters, building in capacity and knowledge now or whether they should make it part of the next deployment cycle. Pulling the trigger early might put you at risk of making the wrong decision in terms of vendor or protocol. Adopting late might put you behind the competition or make you rush to deploy a system that is not well understood by the local staff.

Voice over the Internet Protocol, a.k.a. Voice over IP, or VoIP, is a huge topic. Those trying to really understand how VoIP systems operate and the issues associated with their deployment must delve into protocols and architecture requirements such as power over Ethernet, or PoE. New security issues arise because voice is now packetized on the data network and accessible via ubiquitous wireless links. Quality-of-service issues associated with mixing data and voice on the same network cause headaches as network administrators are inundated with real-time data. Interconnecting IP voice connections with the public switched telephone network (PSTN) and unified communications (UC) brings additional concerns and increasing workloads to the ...