This book is based on the authors' personal experiences in the technical field and public standards documents created by the 3rd Generation Partnership Project (3GPP), the Internet Engineering Task Force (IETF), and other standards development organizations. The opinions and views of the authors are solely those of the authors and do not necessarily represent the views of organizations where the authors work. Throughout this book the authors have attempted to make it clear when something is an opinion or a view of the authors. Some of the examples, feature lists, and identified ambiguities may not apply universally to all deployments and products.

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