e today can have far-reaching effects on the produc- tivity and cost-effectiveness of your company's communications. As an equipment ven- dor, we advise numerous customers on the available options and network designs and provide anecdotes as to what has worked and warnings to what has not in this epic jour- ney to end-to-end rich media communications. This book lays out charts and navigational assistance to help you sail these waters suc- cessfully. A variety of decision makers can benefit from this book, whether you are inter- ested in the details of the industry transition from Time Division Multiplexing (TDM) SIP, you are an executive who has to decide where to direct the communications invest- ments of your company, or you are an IT staff member or consultant challenged with implementing these technologies. The book is divided into three easy-to-use sections to address each of these interest groups: Part I, "From TDM Trunking to SIP Trunking," is for the beginner or executive read- er and covers an overview of the industry transition, trends in the communications industry, an introduction to transitioning your network from TDM to SIP trunking, and a sample cost analysis. Part II, "Planning Your Network for SIP Trunking," is for the IT staff member or con- sultant responsible for the planning, architecture, design, and rollout logistics of the network transition. This section provides information on the network design consid- erations, dial plan operation, phases of rollout, service provider offering evaluation, and much more. Part III, "Deploying SIP Trunking," is for the network engineer who implements the changes and configures the equipment. This section provides information on net- work deployments and configuration examples including several case studies. XX SIP Trunking Goals and Methods The goal of this book is to help you understand, decide, and execute the transition from using TDM trunking to SIP trunking in your network for PSTN access. If you have already made the decision to go forward with this 