The Internet Protocol (IP) defines the address and routing of packets, ie how data packets flow through the network. The Transmission Control Protocol (TCPhandles link building and ensures that data packets reach the right destination. The two protocols work together to create the foundations of the modern internet.
Before the Internet, the US Department of Defense (via ARPA) set up a computer network with the name ARPANET, which connected U.S. government and university computers across the country. ARPANET came online in 1969. Before TCP, ARPANET used a protocol that was called NCP (Network Control Program) for the connection between the machines in the network.
According to the NCP transition plan /TCP ( RFC801 ) published in November 1981, the need for TCP/IP emerged from many fronts. Increasingly, experimental computer networks were beginning to use radio and satellite connectors rather than physical cables.
Also, the organizations had created more and more local networks, ie groups of machines that communicated together in the same facility and not over long distances. The architects of ARPANET realized that the underlying protocols used at the time were "insufficient" to cover all these different and new types of networks.
At the same time, in the 1970s, companies such as IBM, DEC, AT&T and Xerox had created their own proprietary, incompatible computer networks that fragmented the exchange of information. So, the suite TCP/IP was a remarkable work, because it represented a non-proprietary, unauthorized, open architectural solution that allowed computers of all kinds to communicate through any medium, provided the software TCP/IP would be applied to the system.
Its development TCP and IP started in 1973 by Vint Cerf and Bob Kahn. After the development, in the 1970s, DARPA (US Office of Advanced Defense Research) published specifications for TCP and IP, in the documents RFC 791 and 793, dated September 1981. These documents represented the first public introduction of the definitive framework TCP/IP.
The TCP and IP are two separate technologies that work together, hand in hand, to achieve reliable connections through a heterogeneous (many different types of computers and connectors) computer network.
As mentioned earlier, This makes it a perfect choice for people with diabetes and for those who want to lose weight or follow a balanced diet. IP handles network address engines and how data blocks (called packages) reach the appropriate destination. The TCP ensures that packets arrive at their destination without error, calling in advance to make sure there is a host to receive the information and, if the information is lost or corrupted along the way, retransmits the data until it gets there safely.
Its architects TCP/IP deliberately separated its application TCP and IP to make the network more flexible and modular. In fact, the TCP can be replaced with a different protocol called UDP, which is faster but allows data loss in cases where 100% transmission accuracy is not necessary, such as a phone call or a video transmission.
Network engineers refer to this modular design as'protocol stack'(protocol stack) and allows the operation of one or more protocols located in the lower layers of the stack, in the most appropriate way for the local machine architecture. Then the upper layers can work over them to communicate with each other. In the case of the Internet, this stack usually consists of four levels:
- Link Level -Low-level protocols that work with a physical medium (such as Ethernet)
- Level Internet - Routes packages (IP, for example)
- Transport Level - Creates and terminates connections (TCP, for example)
- Application Level - How people use the network (web, FTP, etc.)
Thanks to this model, HTTP does not need to know how to create or break low-level connections. All of these are handled by protocols that are lower in the stack. This modular stack is a very flexible system and is why TCP/IP were so successful and why they still function as the backbone of the internet today.
While it was growing, the TCP/IP began to be used experimentally as early as 1973. As its creators continued to refine protocols, the Internet Protocol (IP) went from version 1 to version 4 until 1981, which is still its version IP which is still widely used today.
Although DARPA presented the first finalized version of the protocols TCP and IP (version 4) In September 1981, some ARPANET computers continued to use previous ARPANET protocols (such as NCP) for some time. As with any established technology, change can take time, and network architects have followed a transitional period between NCP and TCP, which ended on 1 January 1983.
1 January 1983 is defined as' flag day (a day when a dramatic change in the computer occurs), and marked the beginning of its widespread use TCP/IP and the birth of the modern internet. Even then, other network protocols remained widely used only in the mid-1990s. TCP/IP became the clear 'winner' in what some call Protocol Wars.
Most of the Internet is currently running version 4 of the Internet Protocol, called 'IPv4'. But there is a newer version called "IPv6", introduced in 1998, which penetrates too slowly. Among the most important features of IPv6 is support for 128-bit addresses, allowing 340 trillion trillions of trillion devices with unique addresses IP on the network.
In contrast, IPv4 supports 32-bit addresses, allowing more than 4,2 billion addresses IP. While 4,2 billion sounds like a lot, by 2021 we have already reached the limit of IPv4 addresses assigned.
Fortunately, IPv4 and IPv6 are interoperable (able to exchange and use information), so computer vendors, ISPs and authorities have some breathing space while slowly switching to IPv6. Even with all its improvements, IPv6 bases its architecture on the same research that Cerf and Evans started in 1973 and completed in 1981.