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What is TCP Protocol

If you've arrived here, you're definitely interested in learning more about TCP. One of the most important protocols in the Internet protocol suite is the Transmission Control Protocol (TCP). Its origins may be traced back to the first network deployment when it was used to supplement the Internet Protocol (IP). As a result, TCP/IP is a term that is frequently used to refer to the complete package. This article will take you through the entire concept, and at the end, you will not only know what TCP is, but you will be well-versed in the matter.

Security Tutorials Sep 17, 21 by Nisal N 9 min Read
What is TCP Protocol

If you've arrived here, you're definitely interested in learning more about TCP. One of the most important protocols in the Internet protocol suite is the Transmission Control Protocol (TCP). Its origins may be traced back to the first network deployment when it was used to supplement the Internet Protocol (IP). As a result, TCP/IP is a term that is frequently used to refer to the complete package. This article will take you through the entire concept, and at the end, you will not only know what TCP is, but you will be well-versed in the matter.

What is the Transmission Control Protocol?

Transmission Control Protocol is a standard for establishing and maintaining a network communication in which application software may interchange data. In simple words, It's a connection-focused communications system that makes it easier to send and receive messages across a network of computers.

It's also the most widely used protocol in Internet Protocol networks. TCP is used in conjunction with the IP, which specifies the way systems exchange data bits. 

TCP and IP are the fundamental rules that govern the internet. TCP is defined by the Internet Engineering Task Force (IETF) in RFC 793, a Request for Comment (RFC) standards protocol. They are often attributed to TCP/IP.

How does TCP/IP operate?

TCP permits information to be sent to both ends. This implies that TCP-enabled systems may transmit data in real-time, much like a phone call. Segments, also known as packets, are the primary units of data transfer in the protocol. 

Segments can contain control data concerning the payload and are restricted to 1,500 bytes. The TCP program in the operating system's network protocol stack is in charge of initiating and closing end-to-end connections along with data transmission.

TCP software is managed via particular gateways by various network programs, such as internet browsers or servers. Two specified endpoints must always be used to identify each connection (client and server). It makes no difference which side takes on the client role and which side takes on the server.

Since it is a connection-oriented standard, it establishes and maintains a connection until the computer programs on both ends have stopped communicating. It specifies the splitting of application data into packets that networks could perhaps deliver, receive and send packets from the network layer, maintain flow grip, cover re-transmission of scraped packets, and acknowledge all packets that reach because it is designed to offer error-free data transmission.

When a website transmits an HTML file to a user, it does so via the hypertext transfer protocol commonly known as HTTP. The HTTP program layer requests that the TCP layer establish the session and transmit the file. The TCP layer splits the file into data packets, numbers them, and sends them to the IP layer for transmission one by one.

Even though every packet in the transmission has identical source and destination IP addresses, packets may also be delivered through numerous paths. Depending on lost packet numbers, the TCP software layer in the client system waits till all the packets have reached before acknowledging those it gets and requesting re-transmission of those it does not. After that, the TCP layer puts the packets together into a folder and sends them to the intended receiver.

This fault detection procedure, which involves re-transmissions and rearranging packets after receiving, can add delay to a TCP stream. Highly time-sensitive systems like voice over IP (VoIP), video streaming, and gaming typically utilize a transport protocol like User Datagram Protocol (UDP) because it lowers delay and jitter (varying in latency) by eliminating the need to rearrange packets or retransmit lost data.

Since it has no method of determining whether the application has completed its back-and-forth transmission, UDP is categorized as a datagram protocol or connectionless procedure. Instead of repairing erroneous data packets as TCP does, UDP simply discards them and leaves more thorough error detection to the application layer.

So, why do we use the Transmission Control Protocol?

TCP is a protocol for arranging data so that it may be transmitted securely between the server and the client. It ensures data integrity is transferred across the network, no matter how much of it is exchanged. As a result, it's used to send data from other relatively high protocols that demand that all data be received. Here are some examples:

  • File Transfer Protocol (FTP), Secure Shell (SSH), and Telnet - For file sharing among peers and login into another user's system to view a file in the case of Telnet.
  • HTTP - It is used for web access.
  • For sending and receiving email, Post Office Protocol (POP), Simple Mail Transfer Protocol (SMTP), and Internet Message Access Protocol (IMAP) are used.

These instances are all part of the TCP/IP stack's app layer, and they all deliver data to TCP on the transport layer.

When should you choose TCP?

The sender and the recipient usually agree on the maximum size of the data packets to be transferred even before the first data is delivered (MSS). By default, segments can include up to 1,500 bytes of payload data, with at least 20 bytes for the TCP header and another 20 bytes for the IP header.

If you require a specific size, provide it in the Options box as mentioned above, but keep in mind that the payload data will be reduced proportionally.

With the maximum packet size of 1.46 kilobytes (0.00146 megabytes), a TCP packet can only deliver 1.46 kilobytes (0.00146 megabytes) of data. Web information such as pictures, which can be numerous hundred kilobytes in size, is sent through the TCP protocol using segmentation.

In this scenario, the data packet is separated into multiple blocks, numbered, and then delivered randomly before being transported. Because the receiver must accept the arrival of each segment and may reconstruct the true sequence based on the sequence numbers, the receiver can simply reassemble the sent payload data after the TCP transfer.

Also, note that the retransmission timeout (RTO) mechanism is utilized if the sender does not get acknowledgement for a sent segment. If this timeout elapses before a reaction has been sent after a packet is sent, the packet is immediately resent. The timer's duration is changed continually by an algorithm and is focused on the personal transmission speed.

Importance of Transmission Control Protocol

TCP is significant since it sets the rules and processes for the transmission of data across the internet. It serves as the cornerstone for the internet as we know it today, ensuring that data is sent consistently independent of location, technology, or software.

As a result, it is both adaptable and extendable, meaning that new protocols may be added to it, and they will be accommodated. It's also nonproprietary, which means it doesn't belong to anyone individual or corporation.

Things to know before you use TCP:

The TCP protocol has influenced the history and development of computer networks for more than half a century. TCP is readily coupled with the Internet protocol (IP), which has a lengthy history and numerous benefits over other protocols like UDP and SCTP. The following are the most significant characteristics:

  • After the three-way handshake, TCP is connection-oriented and allows two-way communication between two endpoints.
  • TCP is dependable because it assures that all data is fully delivered. The recipient may compile the data in the right sequence.
  • Exclusive data fragments till 1,500 bytes (involving headers) can be transmitted using TCP.
  • TCP is located in the OSI model's transport layer (layer 4).
  • TCP is widely known as the TCP/IP protocol stack since it is used in combination with the Internet Protocol (IP).
  • The default size of the TCP header measures 20 bytes. Additional choices of up to 40 bytes can be added.

Takeaway

This article not only covered what Transmission Control Protocol is but additionally, it talked about the functioning of TCP, its uses and its importance. The article also stated the most important facts regarding the Transmission Control Protocol

We hope that this article was able to address all of your concerns and was helpful as well. Share this with your friends and colleagues to help spread the word.

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Nisal N

Computers has always fascinated me since I was a kid and here we are. I love travelling for 2 reasons: the first one to see a new part of the world and second (the most important one) to experience the rich culture hidden among the country and people. I'm pretty good at cooking but very poor when it comes to baking.

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