The IT Stuff

The Internet Protocol Suite (commonly known as TCP/IP) is the set of communications protocols used for the Internet and other similar networks. It is named from two of the most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were the first two networking protocols defined in this standard.
The [...]

The Transmission Control Protocol (TCP) level of the TCP/IP transport protocol is connection-oriented that is it  means that, before any data can be transmitted, a reliable connection must be obtained and acknowledged.
There are two scenarios where a three-way handshake will take place:

Establishing a connection (an active open)
Terminating a connection (an active close)

1. TCP(Transmission Control Protocol).

TCP (Transmission Control Protocol) is the most commonly used protocol on the Internet. The reason for this is because TCP offers error correction. When the TCP protocol is used there is a “guaranteed delivery.” This is due largely in part to a method called “flow control.” Flow control determines when data [...]

The four layers of the TCP/IP model are:

Application (Process)
Host-to-host (Transport)
Internet
Network Access (Physical and Data link)

The two protocols that function at the host-to-host layer of the TCP/IP model are TCP and UDP. (TCP is a connection-oriented, reliable protocol. UDP is a connectionless and unacknowledged protocol.).The protocol number for TCP is 6. The protocol number for UDP [...]