Transport Layer – TCP and UDP
Oliver C. Ibe · 2017
This chapter discusses the transport-layer protocols, which include transmission control protocol (TCP) and user datagram protocol (UDP). It covers TCP basics, TCP window flow control, TCP congestion control and UDP model. To avoid congestion collapse, several congestion control schemes have been proposed for TCP. These include slow start, congestion avoidance, fast retransmit and fast recovery. TCP uses several methods of communication to handle the reliable delivery of data. TCP is used for applications that require high reliability but are less time critical, whereas UDP is used for application that are time sensitive but do not require high reliability. A TCP connection is established between a client host and a server host. A SYN flood attack occurs when a client sends a great number of SYN requests to the server and when the server returns a SYN ACK, the client simply ignores it and does not return an ACK.