Understanding TCP and UDP
As we discussed earlier in this chapter in the Transport layer section, TCP and UDP are the main protocols that are used to transfer data across a network. The delivery mechanisms that they have are different from each other. TCP has acknowledgments, sequence numbers, and flow control in transferring data process to provide a guaranteed delivery, whereas UDP does not provide a guaranteed delivery but provides a delivery with best efforts.
Transmission Control Protocol
TCP performs a three-way handshaking process before the protocol establishes the session. This is done in order to provide a guaranteed delivery. Refer to the following figure to understand the three-way handshaking process:
From the preceding image, imagine that Carol's device wants to transfer data to Bryan's device and that they need to perform a three-way handshaking process. First, Carol's device sends a packet to Bryan's device with the synchronize (SYN) flag enabled. Once Bryan...
