The History of the Internet and its Protocols
Introduction
The internet revolutionized communication. It enabled messages to be sent across the world instantaneously, allowing us to have access to things like news and entertainment as soon as they happen. It has changed the way we live, and the way we work.
This “Information Superhighway” has an equally impressive infrastructure. The internet is highly modularized and runs on an extremely diverse set of hardware and software. In order for this diverse set of hardware and software to be able to communicate with each other, they need to agree on how they should communicate. They need to speak the same language.
These agreements are called communication protocols. Communication protocols often take the form of technical standards, which are documents maintained by various organizations such as the Internet Engineering Task Force (IETF), Institute of Electrical and Electronics Engineers (IEEE), and the International Organization for Standardization (ISO).
The set of communication protocols by which internet communications are standardized is called the Internet Protocol Suite. The Internet Protocol Suite is organized into four layers, from the ground-level communications (link layer) to higher-level communications (application layer). The Internet Protocol Suite grew over time as hardware and software requirements changed, but protocols became more important as computers were added to the early internet.
J.C.R. Licklider and the Conceptualization of the Internet

The earliest ideas for a computer network were formulated by computer scientist J. C. R. Licklider, who at the time was a Vice President at Bolt, Beranek and Newman (BBN). In 1960, Licklider published an essay titled “Man-Computer Symbiosis” in which the idea of a network of computers arises in his discussion of the mismatch is speed between man and computers. In the essay, he writes:
Any present-day large-scale computer is too fast and too costly for realtime cooperative thinking with one man. Clearly, for the sake of efficiency and economy, the computer must divide its time among many users. Timesharing systems are currently under active development. […]
It seems reasonable to envision, for a time 10 or 15 years hence, a “thinking center” that will incorporate the functions of present-day libraries together with anticipated advances in information storage and retrieval […] The picture readily enlarges itself into a network of such centers, connected to one another by wide-band communication lines and to individual users by leased-wire services. In such a system, the speed of the computers would be balanced, and the cost of the gigantic memories and the sophisticated programs would be divided by the number of users.
In October 1963, Licklider was appointed head of the Behavioral Sciences and Command and Control programs at the Defense Advanced Research Projects Agency (DARPA). Licklider stressed the importance of computer networking to his successors at DARPA, Ivan Sutherland, Bob Taylor, and MIT researcher Lawrence G. Roberts. At this point, the conceptual groundwork for the internet was born and the call to action was made.
The First Network and the Advent of Packet Switching

In 1965, the first wide-area computer network was built, which connected a computer in California with a computer in Massachusetts using a low speed dial-up telephone line. This network used circuit switching, which establishes a dedicated channel (or circuit) for the duration of a transmission. it wasn’t long until circuit-switched telephone lines were deemed inadequate.
In the years prior, Leonard Kleinrock of MIT had mentioned to Lawrence Roberts, a program manager and office director at DARPA, about the feasibility of using packet-switching techniques invented by computer scientist Donald Davies. Packet switching is when a message is divided into packets and the packets are sent individually. This allows packets to take different (and potentially more efficient) routes and be reassembled at the destination. This disassembling and reassembling of messages into packets is called demultiplexing (demuxing) and multiplexing (muxing) respectively.
In August 1968, a request for quotation (RFQ) was issued for the development of the packet switcher called an Interface Message Processor (IMP). The RFQ was won in December 1968 by a group headed by Frank Heart at Bolt Beranek and Newman (BBN). In September 1969, the first IMP was installed at UCLA under the guidance of Kleinrock. The computer at UCLA became the first node of what was called the Advanced Research Projects Agency Network (ARPANET) and what would later become the internet.
(Read more: IMP Protocol)
The Network Control Program

In the following years, more and more Hosts (network-connected computers) were being added to ARPANET. Multiple host computers of different types, speeds, word lengths, operating systems, etc. could be connected to a single IMP. To transmit data to another host on the network, a Host would pass a message to its IMP, which would then pass the message through other IMPs until it arrived at its destination IMP. The destination IMP would then pass the message to the destination Host.
During this time, there was a vision for a hierarchy of network protocols, including Host-to-Host chat (Telnet) and file-sharing (FTP), but first the groundwork needed to be laid down. The Network Control Program (NCP) was developed to establish connections, break connections, switch connections, and control flow. The NCP provided a transport layer and was the predecessor to the TCP/IP protocols in use today.
(Read more: RFC about NCP)
The Transition to TCP/IP and Beyond

In December 1970, the NCP was finished. As NCP was deployed from 1971–1972, people were starting to develop applications for it. Among these initial applications included electronic mail, which was introduced in 1972.
The NCP was tightly coupled to ARPANET infrastructure, and this caused some limitations. For instance, the NCP was unable to address networks further downstream than a destination IMP on ARPANET. The NCP also did not have the ability to resolve transport errors and packet loss. Khan therefore devised a plan for a new protocol, which would eventually be called the Transmission Control Protocol/Internet Protocol (TCP/IP).
Conclusion
In the early days of the internet, the IMP and the network lines fulfilled the role of the Link Layer, the NCP fulfilled the role of the Transport Layer, and the electronic mail was a successful example of the Application Layer. As requirements change and as there are advances in science and technology, new protocols will be developed to maintain and enhance the current state of the internet.
(Read more/listen: The Man Who Made You Put Away Your Pen)
References
- http://memex.org/licklider.pdf
- https://tools.ietf.org/html/rfc1180#section-3
- https://tools.ietf.org/html/rfc1122
- http://www.tcpipguide.com/
- https://technet.microsoft.com/en-us/library/cc958821.aspx
- http://www.dummies.com/programming/networking/network-basics-osi-data-link-layer/
- https://cse.sc.edu/~wyxu/515Fall08/slides/review-partial.pdf
- http://www.internetsociety.org/internet/what-internet/history-internet/brief-history-internet
- http://www.livinginternet.com/i/ii_ncp.htm
- http://bitsavers.informatik.uni-stuttgart.de/pdf/bbn/imp/BBN1822_Jan1976.pdf
- http://www.rfc-editor.org/rfc/rfc33.txt
- http://www.livinginternet.com/i/ii_ncp.htm
- Wikipedia