Networking and the Internet touch our lives in untold ways every day. From onnecting our computers together at home and surfing the net at high speeds to editing and sharing digital music and video, computer networking has become both ubiquitous and indispensable. 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.