First Wide Area Computer Network example essay topic

History of the internet Introduction The Internet has revolutionized the computer and communications world like nothing before. The invention of the telegraph, telephone, radio, and computer set the stage for this unprecedented integration of capabilities. The Internet is a world-wide broadcasting capability, a mechanism for gathering information, and a medium for communication and interaction between individuals and their computers without regard for geographic location. The Internet represents one of the most successful examples of the benefits of sustained investment and commitment to research and development of information infrastructure.

Beginning with the early research in packet switching, the government, industry and academia have been partners in evolving and deploying this exciting new technology. Today, the average person commonly uses terms like and web. The Internet today is a widespread information infrastructure, the initial prototype of what is often called the National Information Infrastructure. Its history is complex and its influence reaches not only to the technical fields of computer communications but throughout society as we move toward increasing use of online tools to accomplish electronic commerce, information acquisition, and community operations. The Initial Internet Concepts The original ARPANET grew into the Internet.

Internet was based on the idea that there would be multiple independent networks, beginning with the ARPANET as the pioneering packet switching network, but soon to include packet satellite networks, ground-based packet radio networks and other networks. In this approach, the choice of any individual network technology was not dictated by a particular network architecture but rather could be selected freely by a provider and made to interwork with the other networks. Up until that time ther was only one general method for federating networks. This was the traditional circuit switching method where networks would interconnect at the circuit level, passing individual bits on a synchronous basis along a portion of an end-to-end circuit between a pair of end locations. Kleinrock had shown in 1961 that packet switching was a more efficient switching method. Along with packet switching, special purpose interconnection arrangements between networks were another possibility.

While there were other limited ways to interconnect different networks, they required that one be used as a component of the other. In an open-architecture network, the individual networks may be separately designed and developed and each may have its own unique interface which it may offer to users and other Internet providers. Each network can be designed in accordance with the specific environment and user requirements of that network. There are generally no constraints on the types of network that can be included. The idea of open-architecture networking was first introduced by Kahn shortly after having arrived at DARPA in 1972.

This work was originally part of the packet radio program, but then became a separate program in its own right. At the time, the program was called Internetting. Kahn first contemplated developing a protocol local only to the packet radio network, since that would avoid having to deal with the multitude of different operating systems, and continuing to use NCP. However, NCP did not have the ability to address networks (and machines) further downstream than a destination IMP on the ARPANET and thus some change to NCP would also be required. (The assumption was that the ARPANET was not changeable in this regard). NCP relied on ARPANET to provide end-to-end reliability.

If any packets were lost, the protocol would come to a halt. Kahn decided to develop a new version of the protocol which could meet the needs of an open-architecture network environment. This protocol would eventually be called the Transmission Control Protocol / Internet Protocol (TCP / IP). While NCP tended to act like a device driver, the new protocol would be more like a communications protocol. Four ground rules were critical to Kahn's early thinking: + Each distinct network would have to stand on its own and no internal changes could be required to any such network to connect it to the Internet. + Communications would be on a best effort basis.

If a packet didn't make it to the final destination, it would shortly be retransmitted from the source. + Black boxes would be used to connect the networks; these would later be called gateways and routers. There would be no information retained by the gateways about the individual flows of packets passing through them, thereby keeping them simple and avoiding complicated adaptation and recovery from various failure modes. + There would be no global control at the operations level. Other key issues that needed to be addressed were: + Algorithms to prevent lost packets from permanently disabling communications and enabling them to be successfully retransmitted from the source. + Providing for host to host "pipelining" so that multiple packets could be enroute from source to destination at the discretion of the participating hosts, if the intermediate networks allowed it.

+ Gateway functions to allow it to forward packets appropriately. This included interpreting IP headers for routing, handling interfaces, breaking packets into smaller pieces if necessary, etc. + The need for end-end checksums, reassembly of packets from fragments and detection of duplicates, if any. + The need for global addressing + Techniques for host to host flow control.

+ Interfacing with the various operating systems + There were also other concerns, such as implementation efficiency, internetwork performance, but these were secondary considerations at first. Kahn began work on a communications-oriented set of operating system principles while at BBN and documented some of his early thoughts in an internal BBN memorandum entitled. At this point he realized it would be necessary to learn the implementation details of each operating system to have a chance to embed any new protocols in an efficient way. Thus, in the spring of 1973, after starting the internetting effort, he asked Vint Cerf to work with him on the detailed design of the protocol.

Cerf had been intimately involved in the original NCP design and development and already had the knowledge about interfacing to existing operating systems. They teamed up to spell out the details of what became TCP / IP. The give and take was highly productive and the first written version of the resulting approach was distributed at a special meeting of the International Network Working Group (IN WG) which had been set up at a conference at Sussex University in September 1973. Some basic approaches emerged from this collaboration between Kahn and Cerf: + Communication between two processes would logically consist of a very long stream of bytes (they called them octets).

The position of any octet in the stream would be used to identify it. + Flow control would be done by using sliding windows and acknowledgments (acks). The destination could select when to acknowledge and each ack returned would be cumulative for all packets received to that point. + It was left open as to exactly how the source and destination would agree on the parameters of the windowing to be used.

Defaults were used initially. + Although Ethernet was under development at Xerox PARC at that time, the proliferation of LANs were not envisioned at the time, much less PCs and workstations. The original model was national level networks like ARPANET of which only a relatively small number were expected to exist. Thus a 32 bit IP address was used of which the first 8 bits signified the network and the remaining 24 bits designated the host on that network.

This assumption, that 256 networks would be sufficient for the foreseeable future, was clearly in need of reconsideration when LANs began to appear in the late 1970's. The original Cerf / Kahn paper on the Internet described one protocol, called TCP, which provided all the transport and forwarding services in the Internet. Kahn had intended that the TCP protocol support a range of transport services, from the totally reliable sequenced delivery of data to a service in which the application made direct use of the underlying network service, which might imply occasional lost, corrupted or reordered packets. A major initial motivation for both the ARPANET and the Internet was resource sharing. For example allowing users on the packet radio networks to access the time sharing systems attached to the ARPANET. Connecting the two together was far more economical that duplicating these very expensive computers.

However, while file transfer and remote login were very important applications, electronic mail has probably had the most significant impact of the innovations from that time. Email provided a new way of how people could communicate with each other, and changed the nature of collaboration, first in the building of the Internet itself and later for much of society. There were other applications proposed in the early days of the Internet, including packet based voice communication, various models of file and disk sharing, and early worm programs that showed the concept of agents and, of course, viruses. A key concept of the Internet is that it was not designed for just one application, but as a general infrastructure on which new applications could be conceived. History of the Future The Internet has changed much in the two decades since it came into existence.

It was conceived in the time of time-sharing, but has survived into the time of personal computers, client-server and peer to peer computing, and the network computer. It was designed before LANs existed, but has accommodated that new network technology, as well as the more recent ATM and frame switched services. It was seen as supporting a range of functions from file sharing and remote login to resource sharing and collaboration, and has spawned electronic mail and more recently the World Wide Web. But most important, it started as the creation of a small band of dedicated researchers, and has grown to be a commercial success with billions of dollars of annual investment. One should not conclude that the Internet has now finished changing. The Internet, although a network in name and geography, is a creature of the computer, not the traditional network of the telephone or television industry.

It will, indeed it must, continue to change and evolve at the speed of the computer industry if it is to remain relevant. It is now changing to provide such new services as real time transport, in order to support, for example, audio and video streams. The availability of pervasive networking along with powerful affordable computing and communications in portable form, is making possible a new paradigm of nomadic computing and communications. This evolution will bring us new applications. It is evolving to permit more sophisticated forms of pricing and cost recovery, a perhaps painful requirement in this commercial world. It is changing to accommodate yet another generation of underlying network technologies with different characteristics and requirements, from broadband residential access to satellites.

New modes of access and new forms of service will spawn new applications, which in turn will drive further evolution of the net itself. The most pressing question for the future of the Internet is not how the technology will change, but how the process of change and evolution itself will be managed. As this paper describes, the architecture of the Internet has always been driven by a core group of designers, but the form of that group has changed as the number of interested parties has grown. With the success of the Internet has come a proliferation of stakeholders - stakeholders now with an economic as well as an intellectual investment in the network. We now see, in the debates over control of the domain name space and the form of the next generation IP addresses, a struggle to find the next social structure that will guide the Internet in the future. The form of that structure will be harder to find, given the large number of concerned stake-holders.

At the same time, the industry struggles to find the economic rationale for the large investment needed for the future growth. Origins of the Internet The first recorded description of the social interactions that could be enabled through networking was a series of memos written by J.C.R. Licklider of MIT in August 1962 discussing his Galactic Network concept. He wanted a globally interconnected set of computers through which everyone could quickly access data and programs from any site. The concept was very much like the Internet of today. Licklider was the first head of the computer research program at DARPA, starting in October 1962. While at DARPA he convinced his successors at DARPA, Ivan Sutherland, Bob Taylor, and MIT researcher Lawrence G. Roberts, of the importance of this networking concept.

Leonard Kleinrock at MIT published the first paper on packet switching theory in July 1961 and the first book on the subject in 1964. Kleinrock convinced Roberts of the advantage of communications using packets rather than circuits, which was a major step along the path towards computer networking. The other major step was to make the computers talk together. To explore this, in 1965 working with Thomas Merrill, Roberts connected the TX-2 computer in Mass. to the Q-32 in California with a low speed dial-up telephone line creating the first wide-area computer network ever built. The result of this experiment was the realization that the time-shared computers could work well together, running programs and retrieving data as necessary on the remote machine, but that the circuit switched telephone system was totally inadequate for the job.

Kleinrock's conviction of the need for packet switching was confirmed. Due to Kleinrock's early development of packet switching theory and his focus on analysis, design and measurement, his Network Measurement Center at UCLA was selected to be the first on the ARPANET. All this came together in September 1969 when BBN installed the first IMP at UCLA and the first host computer was connected. Computers were added quickly to the ARPANET during the following years, and work proceeded on completing a functionally complete Host-to-Host protocol and other network software. In December 1970 the Network Working Group (NW) working under S. Crocker finished the initial ARPANET Host-to-Host protocol, called the Network Control Protocol (NCP). In October 1972 Kahn organized a large, very successful demonstration of the ARPANET at the International Computer Communication Conference (I ).

This was the first public demonstration of this new network technology to the public. It was also in 1972 that the initial hot application, electronic mail, was introduced. In March Ray Tomlinson at BBN wrote the basic email message send and read software, motivated by the need of the ARPANET developers for an easy coordination mechanism. Commercialisation of the Technology Commercialisation of the Internet involved not only the development of competitive, private network services, but also the development of commercial products implementing the Internet technology. In the early 1980's, dozens of vendors were incorporating TCP / IP into their products because they saw buyers for that approach to networking. Unfortunately they lacked both real information about how the technology was supposed to work and how the customers planned on using this approach to networking.

Many saw it as a nuisance add-on that had to be glued on to their own proprietary networking solutions: SNA, DECNet, Netware, NetBios. The DoD had mandated the use of TCP / IP in many of its purchases but gave little help to the vendors regarding how to build useful TCP / IP products. In 1985, recognizing this lack of information availability and appropriate training, Dan Lynch in cooperation with the IAB arranged to hold a three day workshop for ALL vendors to come learn about how TCP / IP worked and what it still could not do well. The speakers came mostly from the DARPA research community who had both developed these protocols and used them in day to day work. About 250 vendor personnel came to listen to 50 inventors and experimenters. The results were surprises on both sides: the vendors were amazed to find that the inventors were so open about the way things worked and the inventors were pleased to listen to new problems they had not considered, but were being discovered by the vendors in the field.

After two years of conferences, tutorials, design meetings and workshops, a special event was organized that invited those vendors whose products ran TCP / IP well enough to come together in one room for three days to show off how well they all worked together and also ran over the Internet. In September of 1988 the first Interop trade show was born. 50 companies made the cut. 5,000 engineers from potential customer organizations came to see if it all did work as was promised. It did. Why Because the vendors worked extremely hard to ensure that everyone's products interoperate d with all of the other products - even with those of their competitors.

The Interop trade show has grown immensely since then and today it is held in 7 locations around the world each year to an audience of over 250,000 people who come to learn which products work with each other in a seamless manner, learn about the latest products, and discuss the latest technology. In parallel with the commercialisation efforts that were highlighted by the Interop activities, the vendors began to attend the IETF meetings that were held 3 or 4 times a year to discuss new ideas for extensions of the TCP / IP protocol suite. Starting with a few hundred attendees mostly from academia and paid for by the government, these meetings now often exceeds a thousand attendees, mostly from the vendor community and paid for by the attendees themselves. Network management provides an example of the interplay between the research and commercial communities. In the beginning of the Internet, the emphasis was on defining and implementing protocols that achieved inter operation. As the network grew larger, it became clear that the sometime ad hoc procedures used to manage the network would not scale.

Manual configuration of tables was replaced by distributed automated algorithms, and better tools were devised to isolate faults. In 1987 it became clear that a protocol was needed that would permit the elements of the network, such as the routers, to be remotely managed in a uniform way. Several protocols for this purpose were proposed, including Simple Network Management Protocol or SNMP (designed, as its name would suggest, for simplicity, and derived from an earlier proposal called SNMP), HEMS and CMIP. A series of meeting led to the decisions that HEMS would be withdrawn as a candidate for standardization, in order to help resolve the contention, but that work on both SNMP and CMIP would go forward, with the idea that the SNMP could be a more near-term solution and CMIP a longer-term approach. The market could choose the one it found more suitable. SNMP is now used almost universally for network based management.

In the last few years, we have seen a new phase of commercialisation. Originally, commercial efforts mainly comprised vendors providing the basic networking products, and service providers offering the connectivity and basic Internet services. The Internet has now become almost a "commodity" service, and much of the latest attention has been on the use of this global information infrastructure for support of other commercial services. This has been tremendously accelerated by the widespread and rapid adoption of browsers and the World Wide Web technology, allowing users easy access to information linked throughout the globe. Products are available to facilitate the provisioning of that information and many of the latest developments in technology have been aimed at providing increasingly sophisticated information services on top of the basic Internet data communications.

Conclusion What is the reason for the immense success of the World-Wide Web The system requirements for running a server are minimal, so even administrators with limited funds had a chance to become information providers. Because of the intuitive nature of hypertext, many inexperienced computer users were able to connect to the network. Furthermore, the simplicity of the HyperText Markup Language, used for creating interactive documents, allowed these users to contribute to the expanding database of documents on the Web. Also, the nature of the World-Wide Web provided a way to interconnect computers running different operating systems, and display information created in a variety of existing media formats. The possibilities for hypertext in the world-wide environment are endless. With the computer industry growing at today's pace, no one knows what awaits us at the turn of the 21st century.