This book provides a systematic progression from the legacy networks of the past to the Next Generation Convergent networks of the future. The books aims at providing complete background and relevant details that are required to plan, design and deploy modern day core/backbone telecommunication networks. This is book would be useful to individuals associated with most of the areas of the vast telecom as well as data networking spectrum including planning, engineering, network management & operations, installation and commissioning as well as operations and maintenance, besides any knowledge seeker