In this course, we discuss peer-to-peer protocols and local area networks. Part one in this course is to answer the question of how does a peer-to-peer protocol deliver reliable data transfer service across unreliable transmission lines or networks. We focus on several medium access control protocols and their performance analysis. In the second part, we discuss how medium access control protocols coordinate the access to the communication channel so that information gets through from a source to a destination in the same broadcast local area network. We further discuss local area network and wireless LAN.