Building on the successful top-down approach of previous editions, the Sixth Edition of _COMPUTER NETWORKING_ continues with an early emphasis on application-layer paradigms and application programming interfaces (the top layer), encouraging a hands-on experience with protocols and networking concepts, before working down the protocol stack to more abstract layers. This book has become the dominant book for this course because of the authors reputations, the precision of explanation, the quality of the art program, and the value of their own supplements.