This book introduces the characteristics and application of BGP, including five parts sorted into 12 chapters. Part one is understanding advanced BGP, chapter one introduces the basic features of BGP and compares the features between BGP and IGP; chapter two reviews the path attributes of BGP, based on which, illustrating the path selection algorithm at the same time of introducing BGP process and memory usage, path selection information bank and the exchange characteristics of IOS; chapter three expounds the content of performance tuning of BGP, including thinking on TCP, queue optimization and so on; chapter four illustrates many strategy control skills of BGP, including strengthening filter list of BGP strategy, route map, strategy list and so on. Part two and part three introduces enterprise and service provider BGP network, content form chapter five to chapter nine is the core of this book, analyzing the BGP network design of enterprises and operators, including BGP framework and comparison, the internet interface of enterprise network, route reflection and migration alliance, network architecture of service provider. Part four introduces multi-protocol extension of BGP framework, chapter ten to chapter twelve breaking through traditional BGP field to introduce new application in other fields. Part five contains appendix and offers relevant materials.