As development work on wide area networks progressed in the early 1970s, leading to the emergence of the Internet, the TCP / IP protocol was also developed. TCP stands for Transmission Control Protocol, while IP stands for Internet Protocol. The adoption of TCP / IP protocols as the Internet protocol led to the integration of networks into a large network that has grown rapidly to a mark of approximately 2.267 million users at the end of December 2011 (Internet World Stats). Today we have many application service protocols that coexist with TCP / IP as the underlying protocol.

TCP / IP is a transport protocol. It can be used to support applications directly, or other protocols can be overlaid on TCP / IP to provide additional functionality. These protocols include:

• HTTP (Hypertext Transfer Protocol): used by web browsers and web servers to exchange information. On the other hand, when a secure connection is required, the SSL (Secure Socket Layer) protocol or its successor protocol Transport Layer Security (TLS), which use encryption, are used to create a secure connection through the web browser, but this time instead of HTTP. use HTTPS.
• SMTP (Simple Mail Transfer Protocol) – Used to send and receive e-mail through the TCP / IP protocol. Due to its limitation in the message queue, it is normally used with other protocols such as POP3 or IMAP.
• TELNET (Telecommunications network) – Used to connect to remote hosts through a telnet client. This results in your computer becoming a virtual machine while you work on the remote computer as if you were at your desk.
• FTP (File Transfer Protocol): Used to transfer files from one host to another using the FTP client software over a TCP / IP network.
• NNTP (Network News Transfer Protocol) – Used to transport news articles between news servers.

TCP (Transport control protocol) and UDP (User Datagram Protocol) are both Internet protocols used to transport data. IP (Internet Protocol) functions as the underlying protocol of the virtual Internet network. It is found under the UDP and TCP protocols. The IP datagram provides the basic transmission mechanisms for all TCP / IP networks. This includes the Internet, ATMs, local area networks such as Ethernet, and token ring networks. TCP is reliable and connection-oriented. Establish the connection first before transmitting the data and the data can flow in either direction. UDP is a datagram protocol with limited capabilities. You have no guarantee of the arrival of the message at the other end. Datagram packets arrive at their destination in any order and will need to be reassembled. Sometimes UDP is preferred over TCP where there is small amounts of data to transmit, therefore the amount of data received at the destination does not take long to reassemble, making it faster. UDP is also a preferred option for sending data packets that need no response. It also provides a checksum capability to ensure that all data has arrived.

Application protocols are on top of the two basic components of Internet protocols; namely UDP and TCP. These two protocols have a unique trade-off. UDP provides a simple message relay protocol that is flawed by default but has minimal costs due to the fact that there is no need for liability for message relay failures. This protocol is often used for retransmissions; as in video streaming. TCP has guaranteed message delivery, but at the expense of additional messages with much higher latency and storage costs.