Forty years ago, in September 40, DARPA published the final specifications of the TCP / IP protocol suite, which sets out the basic rules for how the Internet works.
See more articles from iGuRu.gr when you search for news on Google.
While TCP / IP was not widely adopted until 1983, this milestone is important because the Internet was based on TCP / IP.
What is TCP / IP?
TCP/IP is a protocol suite consisting of two main protocols designed by Vint Cerf and Bob Kahn, the Transmission Control Protocol (TCP) and the Internet Protocol (IP), respectively.
The Internet Protocol (IP) defines packet addressing and routing, that is, how data packets flow through the network. The Transmission Control Protocol (TCP) handles establishing connections and ensuring that data packets reach their proper destination. The two protocols work together to create the foundation of the modern Internet.
Why was TCP / IP created?
Before the internet, the US Department of Defense (through ARPA) created a computer network called ARPANET, which connected US government and university computers across the country. ARPANET came online in 1969. Before TCP, ARPANET used a protocol called NCP (Network Control Program) to connect between machines on the network.
According to the NCP/TCP Transition Plan ( RFC801 ) published in November 1981, the need for TCP/IP arose from many fronts. More and more, experimental computer networks were beginning to use radio and satellite links 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. Thus, the TCP / IP suite 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 TCP / IP software would be implemented on the system.
The development of TCP and IP began in 1973 by Vint Cerf and Bob Kahn. Following development in the 1970s, DARPA (the U.S. Defense Advanced Research Projects Agency) published specifications for TCP and IP in RFCs 791 and 793 , dated September 1981. These documents represented the first public introduction of the definitive TCP/IP framework.
How does TCP / IP work?
TCP and IP are two separate technologies that work hand-in-hand to achieve reliable connections through a heterogeneous (many different types of computers and connectors) computer network.
As mentioned earlier, IP handles addressing machines on the network and how blocks of data ( called packets ) get to their proper destination. TCP ensures that packets reach their destination without error by calling ahead to make sure there is a host to receive the information and, if the information is lost or corrupted en route, retransmitting the data until it gets there safely.
The architects of TCP / IP deliberately split the application of TCP and IP to make the network more flexible and modular. In fact, 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 video transmission.
Network engineers call this modular design a ' protocol stack ' and it allows one or more protocols located at the lower layers of the stack to be handled in a way that is most appropriate for the architecture of the local machine. The upper layers can then operate on top of them to communicate with each other. In the case of the Internet, this stack typically consists of four layers:
- Link Level -Low-level protocols that work with a physical medium (such as Ethernet)
- Internet level - Routes packets (IP, for example)
- Transport Level - Creates and terminates connections (TCP, for example)
- Application Level - How people use the network (web, FTP, etc.)
Web-based protocols (such as HyperText Transfer Protocol, or HTTP) are located at the Application Level and run over TCP and IP.
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 was so successful and why it still serves as the backbone of the internet today.
When was TCP / IP used?
While in development, TCP / IP began to be used experimentally as early as 1973. As its creators continued to refine protocols, Internet Protocol (IP) went from version 1 to version 4 by 1981, which is still is the IP version that is still widely used today.
Although DARPA introduced the first finalized version of the TCP and IP protocols (version 4) in September 1981, some ARPANET computers continued to use the previous ARPANET protocols (such as NCP) for some time. As with any established technology, change can take time, and the network architects followed a transition period between NCP and TCP, which ended on January 1, 1983.
January 1, 1983, is designated as ' flag day ' (a day when a dramatic change in computing occurs), and marked the beginning of the widespread use of TCP/IP and the birth of the modern Internet. Even then, other network protocols remained widely used, and it was not until the mid-1990s that TCP/IP became the clear 'winner' in what some call the Protocol Wars.
The future of TCP / IP
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 late. Among the most important features of IPv6 is the support for 128-bit addresses, allowing 340 trillion trillions of trillion devices with unique IP addresses on the network.
In contrast, IPv4 supports 32-bit addresses, allowing for over 4,2 billion IP addresses. While 4,2 billion sounds like a lot, we have already reached the limit of IPv4 addresses allocated as of 2021 .
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.
Happy birthday, TCP / IP!
Dimitris hates Mondays...
