This Chapter introduces the lower four layers of the OSI reference model with respect to the TCP/IP protocol suite. The physical and data link layer protocols covered in this Chapter are strictly Ethernet-based. The reason for not including other physical and data link layer protocols is that the Ethernet standards are the most commonly used protocols employed in modern-day Layer 12 networks.
The basics of IP are discussed in this Chapter, as well as the IP-based protocol quartet that is directly transported over Layer 2: ARP, ICMP, PIM, and IGMP.
Understanding TCP is essential to the concepts detailed in later chapters. The basics of TCP operation including the TCP three-way handshake for TCP connection establishment are covered in this Chapter. A more detailed examination of TCP is given through traffic control studies of the TCP sliding window and congestion control mechanisms.