Theory Of Packet Switching

Published Date: 02 Nov 2017

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History of the Internet

The Internet can be defined as massive network comprising of many networks. It is an infrastructure for networking. Millions of machines/computers are connected together globally. This way, a network is formed whereby any of the connected computers can communicate with each other (Abbate 6).

The internet cannot be looked at as a single invention, rather an idea that evolved over decades to what it is now through innovations. It has grown exceptionally fast due to its impact in the many areas of peoples’ lives; for example social circles, education, business, military and many more. The internet is perceived to have started in the early 1990s, but it actually started back in the 1950s (Hauben 8).

Internet Origins

In a wide context, war was responsible for most inventions in 1950s. There was the Korean and Cold War. In the Cold War, USA was pitted against Eastern Bloc and Soviet Union. There was terror of nuclear weapons by Soviet Union against the US soil. When Russians launched the Sputnik satellite, the Americans felt they were being overtaken in terms of technology. This satellite was launched in 1957, threatening the security of the US. It was feared that the Russians would militarize space and also gain an advantage over America.

The US reacted by coming up with ideas to protect themselves and diminish the strategic advantage by Russia. This led to the creation of ARPA (Advanced Research Project Agency). This is currently called DARPA (Defense Advanced Research Projects Agency). This agency was created to innovate technologies to provide high tech edge to the US military, for protection and security. The launching of DARPA was in the late 1950s, but the first system of type of web or interconnected net was formed in 1962. This was an idea by J. C. R. Licklider. He wrote a number of memos on a ‘Galactic Network’ as he called it. The network was essentially capable of information access in the electronic form. This could either be done by programs in computers in a large network or by data. The key factor was all computers in this network would in some way be connected to each other (Markoff 57).

A commissioned study by USAF on the understanding of the best ways of creation of a decentralized communications network to be used in running the military branch during as well as after nuclear strikes was another prominent event in the internet history. The decentralization was to ensure control over airplanes, bombers and nuclear weapons by the military no matter the damage extend. This was overseen by Paul Beran, a RAND Corporation member. He suggested a packet switching technology in networks as a way to achieve the USAF goals (Reid 77).

Theory of Packet Switching

This was developed in 1961 by Leornard Kleinrock. The idea behind it was the inclusion of both the origin as well as destination of in data packets that could be transferred from location to location. Contrary to data that was sent then, this technology enabled data packets to be resent easily from where they originated, should they get lost somewhere on the journey. This was a major improvement over the circuit system that was used by telephone companies at the time.

Many experiments were carried out in the 1960s trying to create efficient and productive computer networks. In 1965, an experiment involving a TX-2 computer in Massachusettes and another Q-32 in California was conducted. It emerged successful and is considered the first success in connecting two computers using a dial up telephone line of low speed. It demonstrated the capacity of computers to connect and share data and programs. This meant that the packet switching technology had to be used to advance the technology since the telephone circuit sets that were used then were impractical (Hanfer & John 97).

ARPANET (The First Internet)

This was the original internet, and the first computer network configuration. It was also a massive springboard with innovations too many of the technologies used today. It was physically constructed in 1968 and had its base as the Honeywell minicomputer. In fact, four Honeywell minicomputers were networked to create the initial ARPANET. The computers/nodes were at four different locations, that is University of California (Santa Barbra), University of California (Los Angeles), SRI (Stanford) and University of Utah. Originally, the network was to have 2.4kbps as the line speed, but there was technology available such that the line speed was boosted to 50 kbps. In 1969, the ARPANET (first internet) was in place, and during 1970s the internet begun building up practicality and steam (Salus 105).

Internet in 1970s

More experiments were conducted with ARPANET. 19 other computers were connected to the network. This number of host computers making up the network’s backbone totaled to 23 computers in 1972. The line speed still remained at 50kbps even with the additional computers. With the ongoing experimentations and innovations and protocol developments, an initial host protocol called Network Control Protocol (NCP) was created (Graham, p.122).

In this same year, the email was created, being cited as the ‘killer app’ of the internet. This made the use of ARPANET to be spread in just the early days and also kept fueling its growth in the preceding years as well as decades. The email was created by Ray Tomlinson who worked for the BBN Corporation. He lay down the foundation on how to send and read messages over ARPANET. This invention was initially crude, but constant innovations over the years have made the email friendlier to the user. The burgeoning network got a social dimension from this application (Battlle 189).

Creation of a New Protocol

Currently, a computer connected to the internet can communicate with millions of millions of other computers. The ARPANET used the NCP protocol which gave it a disadvantage in that only specific computer types could work with the protocol. Many computers wanted to join the ARPANET, in early 1970s, but the NCP protocol only utilized a few. This prompted the creation of a new protocol which would be an open source protocol and more inclusive. This gave the creation of the TCP/IP in 1973. It was, however, first used in 1974 in communication between computers. The first 2 internet pioneers considered to have utilized this protocol were Bob Kahn and Vint Cerf. Within a few years, ARPENET required TCP and NCP was not needed anymore. This protocol is still used to date (Campbell & Aspray 95).

The Expansion of ARPANET

The 1970s saw to the unfolding of numerous innovations, which led to the expansion of ARPANET, past the US and into the world. The Sputnik satellite got the internet idea into motion and less than two decades later, it again caused the initial transatlantic link to be developed. For the very first time, the ARPANET expansion did not need a fixed line. It used waves from satellite radio for data packet transmission. The SATNET was the very first satellite link. It effectively brought a connection between Europe (Norway specifically) and the USA. Norway then connected remaining parts of Europe to the computer network. The ARPANET ceased to be just a project for the military and grew bigger. The SATNET project satellites were owned by several countries’ consortium, not by US military (Salus 240).

Improving the Connectivity

Even with the expansion of the SATNET and the ARPANET, thee connection still entailed many cables which was quite unorganized. This prompted the Ethernet cable creation, which is still in use to date. A number of home computers use fixed lines that connect computers via Ethernet cables to modems then to the Internet Service Provider (ISP). The Ethernet provides an easier, practical and more economical way for quicker and data movement from computer to computer or any other device, at a high speed. Ethernet cables made Local Area Network connections simpler and also increased the communication speed between the computers (Battlle 266).

The 1970s also saw the development of the Unix to Unix Copy (UUCP). The innovator for this was Steve Bellovin. This protocol was developed for those computers which ran on Unix platforms, for easy sending and receiving of files. The development of this protocol over the years has made Usenet as it is currently called. This is a network of news group used to send data files, news and emails all over the internet by millions of internet users (Markoff 155). By the 1979, the ARPANET had 111 computers connected to the network, but the speed stayed at 50 kbps.

Internet in 1980s

Many innovations took place, in the 1980s, which brought many drastic changes to the internet. The innovations were facilitated by the availability of much faster, smaller and affordable computers as well as the hardware. Many users and organizations could now access computers. In this decade, the computer hosts in the internet grew to 200,000 from 150. Organizations were created to manage the growing number of internet users (Hauben 45).

ARPANET still dominated the internet in the 1980s even with the establishment of other networks. It was initially for use by the military, but other government programs and research institutions utilized the ARPANET. An example was the National Science Foundation which created the Computer Science Network (CSNET). The network was specifically meant for the conduction of scientific research. Many institutions and organizations were not capable of connecting to ARPANET much as they wanted to. Communication between different research institutions was made easier by CSNET. In 1981, a plan enabling computers, which either used CSNET or ARPANET, to connect to both networks was put in place. This facilitated easier communication for both of the networks with each other (Salus, p. 201).

The Domain Name System (DNS) was another innovation that improved the mode of communication between computers. It was created in 1984. Before this innovation, long numbers were inputted to contact other computers, which was cumbersome. It was hard to memorize and also took a long time. With the DNS system, names have IP (Internet Protocol) numbers. When a name is put in the internet browser, the computer searches for its IP address. When this system became operational, it was not necessary to remember numbers, only names. In 1983, all computers connected to CSNET and ARPANET had to have TCP/IP protocol to connect, the NCP did not work anymore (Reid 302).

By 1985, hardware and technology prices become more affordable. The ARPANET now had over 1,000 host computers connected to it. The Department of Defense felt that the availability of military programs on the network would facilitate easy attacks to the country, hence the separation of the network into MILNET (for the military) and the current ARPANET with no military components for other disciplines. It was still supported by the Department of Defense despite the military not utilizing the network (Campbell & Aspray, p.56).

CSNET sought for a network upgrade by contracting MCI Corporation. The line speed up until now was only 56kbps. New technological innovations saw to the implementation of circuits offering faster speeds for data transfer (25 times faster). New lines called the T-1 lines were implemented with speeds of up to 1.5Mbps. These lines needed new technology. For instance, IBM came up with advanced routers, and the network was to be managed by Merit Company. The new network went online in 1986, and was called National Science Foundation Network (NSFNET). CSNET kept up its operations despite this. By the end of 1980s, the development of T-3 lines was underway, and they were implemented in 1991. This facilitated data transfer speed of up to 45 Mbps (Graham 66).

Internet in 1990s

The internet continued to grow with more innovations being made. Popularity among individual users brought in a social side as well as a commercial side. With the invention of T-3 lines, the CSNET was not needed anymore. This gave room for the rise of a new network called National Research and Education Network (NREN). This was meant to facilitate networking research at high speeds. The early 1990s, the connection of host computers to the internet was around 300,000 (Hanfer and John 89).

The World Wide Web

It was created by Sir Tim Berners-Lee, Robert Caillau and Sir Sam Walker in 1989, who were researching at the European Organization for Nuclear Research (CERN), but was publicly introduced in 1991. This web facilitates easier access to data on the internet. It makes use of hypertext links (code pieces linking sites and computer hosts). Today’s internet is accessed through browsers like Mozilla Firefox or Internet Explorer. The initial browser called Mosaic came up in 1993. It was created by NCSA and headed by Marc Andreessen; and was a graphical browser that was easy to use. Its popularity paved way for the Netscape browser. The web and browsers help view and other media types, as well as navigating form page to page easily by use of hyperlinks. This web became popular because the hypertext links did not have to be bi-directional as required by other platforms. It also did not have licensing restrictions. Other platforms needed special hardware, which was costly, in addition to the software costs (Abbate 77).

Browser wars came up in the 1990s as many people who used the Microsoft Windows software went online. Microsoft effectively promoted Internet Explorer (IE) by bundling it with Windows 98. Netscape fell from its 85% browser share in mid 1990s to less than 1% in 2003, and is currently defunct (Graham, p.88).

Search Engines

The fast web growth made it hard to keep track of its contents, hence a directory was needed. The first search engine created and which was successful was Yahoo. Two students created it, one being Jerry Young. He created ‘Jerry’s Guide to the World Wide Web’ in 1994 but Yahoo (Yet Another Hierarchical Officious Oracle) was incorporated in 1995. It was initially a website directory, but is now a web portal offering many web oriented services like email, news, IM and streaming radio (Reid 110).

Google took over some years later, being the largest worldwide company in terms of market capitalization. It was initially a research project in a university seeking ways to make web searching more effective. Initial engines used on page data and mega tags to include and rank web pages in directories, which caused no relevant results, to turn up on the sought information. Google created the page rank. It is an algorithm basing relevance of web pages on weighted sum of page ranks which are linked in correspondence to the page. The higher the correlation between web pages and topics, the higher the page relevance to the search term (Battlle 120).

AOL (America Online) also came up in the 1989s, offering its own software which included the most wanted web services like email. It focused on those who perceived the internet as foreign technology that was hard to use, and it used dial up connections. It offers an easy and non-technical way for web and internet experiences. Its services have, however, diminished since the broadband came up (Graham 52).

Social networks have also come up in the last two decades; for example, facebook, twitter, tagged and other sites. Individuals are able to communicate with friends and keep track of their activities through the social networks. Blogging has also come up, where discussions on issues are held.

Conclusion

The internet has been growing since the idea was fast brought up. Its growth has mainly been fueled by things like emailing, social networking and online dating. There are now commercial enterprises taking place on the internet like Amazon, Ebay, Yahoo and AOL. Business has become more convenient and easier with the voice over internet protocol (VOIP), email, online banking, cloud computing and other services. The internet is definitely expected to grow even bigger and more advanced in the years to come.