TCP is an acronym for Transmission Control Protocol and it ensures management and control for data transmissions. It is a protocol that belongs to Layer 4 of the OSI model, more precisely the Transport level.
TCP is a protocol that we use at all the time without realizing it. For example, when we download a file from the Internet, or access a web page or connect in any way to a network device, we use this protocol in all of these situations.
TCP allows us to have the data connections precisely as they were meant to be.
So when we download a file through FTP, the TCP protocol will ensure that each bit in the received data is identical to the data on the download server, ensure that the packets keep their order, and if packages are lost on the road it will resend them.
The advantages of the TCP protocol:
1. Ensures that packages are resent if they are “lost on the road”.
2. Ensures that the order of the packages that arrive are the same as the order they were sent from the server.
3. Establishes a connection between the client and the download server.
TCP ensures package order and retransmission in the event of packet loss with sequence numbers.
Each packet or group of packets has a sequence number associated. If the recipient receives a certain number of packets defined by the sequence number, then it will send back a confirmation message called ACK for these received packets.
Thus, it’s easy for the recipient to figure out what packages they have reached and what packages they need to retransmit. If the source does not receive an ACK acknowledgment for some packages, then it will retransmit those packages.
The initial goal of the “Internet Protocol” network layer was to ensure packet routing within a single network. With the emergence of interconnection between networks, this layer has been added to the communication capabilities between a source network and a destination network.
In the TCP / IP stack, the IP protocol provides packet routing from a source address to a destination address, using some additional protocols, such as ICMP or IGMP. Determining the optimal path between the two networks is at this level.
Communication at the IP level is uncertain, the error correction task being placed at higher levels, for example through the TCP protocol. In IPv4 and not IPv6, packet integrity is provided by checksums.
It deals with all issues related to the actual transmission of an IP packet on a physical connection, including aspects of technologies and transmission media, like OSI Data Link and Physical Layer.
Any device on a network that uses TCP/IP must have an IP address.
IP addresses are essentially unique computer names in a numeric format used to transfer data to the network. IP addresses allow the TCP/IP protocol to confirm requests and receive data from different devices on the network.
The benefits of using TCP/IP:
1. is a protocol independent of any manufacturer;
2. not protected by copyright law;
3. can be used for local LAN as well as global WAN networks;
4. can be used on almost any type of computer.
TCP/IP is a stable, well-defined and complete set of protocols that ensure the transfer of data packets with a very low error rate through a non-homogeneous computer network.