Ethernet and TCP/IP networks

The chapter describes the major hardware components of an IEEE 802.3 carrier sense multiple access (CSMA)/CD network and explains the operation of the CSMA/CD protocol. The chapter lists the fields in the Ethernet data frame, and describes the causes of Ethernet collisions and the process of reducing them. The 802.3 standard defines a range of cable types that can be used for a network based on this standard. These include coaxial cable, twisted pair cable, and fiber optic cable. There are different signaling standards and transmission speeds as well that can be utilized. Ethernet signals are encoded using the Manchester encoding scheme. This method allows a clock to be extracted at the receiver end to synchronize the transmission/reception process. The encoding is performed by a 20 MHz clock signal and the data stream. Collisions are a normal part of a CSMA/CD network. Time monitoring and detection of collisions are the methods by which a node ensures unique access to the shared medium. There are eight fields—preamble, start frame delimiter, source and destination address, length, information, pad, and frame check sequence—in each frame of an 802.3 network.