Evolution and Impact of Computer Networks: A Comprehensive Analysis

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A computer network refers to the infrastructure that allows two or more computers, often called hosts, to communicate with each other and share information as well as other resources. This is usually achieved by defining a set of rules known as protocols which must be observed by all the participating hosts. A computer network is made up of various components and the fundamental layout of both the hardware and software that determines how the network works constitutes the network infrastructure.

Network infrastructure therefore refers to the architecture in terms of the equipment as well as the connections that in total make up the entire network.

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In light of the above, this paper will evaluate network infrastructure and its business application. According to Bellis, little computer networking can be traced back to 1950’s and formed the foundation on which the internet is built (Bell, n. d). Prior to the widespread of the networking that eventually led to the birth of the internet, links were limited by their nature and communications could only take place between two stations.

A further growth saw the introduction of gateways and bridges, but these too were limited to single use. Among the earliest prevalent computer networking methods was the central mainframe method in which terminals were connected via long leased lines. This method was mainly to support research projects through collaboration. Such early networks included ARPANET which linked the University of California, Los Angeles and the Stanford research Institute.

By 1969, a four node network existed after University of Utah was added, and building on these ideas continued such that by the year 1981, the network had grown to over 213 nodes, with a node being added approximately every twenty days (Sunshine, 1989).

The concept of networks has from then continued to scale to the present wired and wireless states. 2. 0 Network Infrastructure The communication lines between computers can take different shapes and forms even in the same network.

They may be in form of copper wires which is the most common as well as telephone lines, optical fibers and nowadays radio channels that take different forms such as Bluetooth otherwise called wireless communication (Introduction to Computer Networks, n. d). At the lowest, a network may take the form of two computers connected through a cable as shown below. Fig. 1 Source: Introduction to Computer Networks A host is connected to another with the help of a line but in most cases, more than one host may be connected, and to the same node.

From a single host point of view, the entire network appears like a black box to which the many other hosts are connected. For communication to take place, different hosts are assigned different addresses while packets pass through different nodes, which in turn determine route such packets will be routed through over the network from one host to another, and the scenario can be represented as shown below. Fig. 2 Source: Introduction to Computer Networks 2. 1 Types of networks Networks may be categorized into groups depending on various criteria.

Such criteria may include geographical coverage and the speeds of nodes and hosts, access restrictions, the communication model employed by the communication nodes and the type of switching model employed by nodes the in the network. However, it should be noted that despite the various technologies and approaches used in network classifications, the underlying principles are the same irrespective of the network category. According to physical location or geographically, a network that covers a small area, spanning over a few kilometers is called a Local Area Network (LAN).

These networks are typically used to connect computers within the same building such as an office environment or even a set of closely located buildings such as in a University campus. For larger distances, the network is either referred to as Metropolitan Area Networks (MAN) or a Wide Area network (WAN). MANs cover a distance of few hundreds of kilometers and usually span over a city. WANs on the other hand are used for connecting hosts that are spread across a large area such as a country, a continent or even the entire globe.

LANs, MANs and WANs co-exist, as LANs are normally connected to the internet and can even access hosts from other remote LANs via MANs and WANs. According to access restrictions, networks can often be classified as either private or public. Private networks belong to the organizations that maintain them such as banks, airline companies, hospitals, insurance companies and so on. Public networks on the other hand are accessible to the general public but only upon payment of a connection fee.

Technically, both private and public could be LANs, MANs or even WANs but often, public networks tend to be WANs. As far as the communication models are concerned, the communication could either be point to point or a broadcast model. A point to point model is said to be in use where a message follows a certain specific route over the network to be received only by the intended host. On the contrary, a message is literary broadcasted over the network and can be seen by any host attached to the network .

An address on the message however indicates which node the message is intended for, while each node on the network looks at the message and ignores it if it does not match its address (Hekmat, n. d). Lastly, networks can be distinguished depending on the switching model that the nodes apply. In point to point, nodes often apply circuit switching or packet switching technology. In circuit switching, a dedicated communication path is usually established to be used by two communicating nodes, while data between the two is sent along as a continuous stream of bits.

The communication channel is retained as long as the two are communicating, after which it is released. In packet switching, data is chopped off into chunks of specific length called packets. These packets are passed from one node to the intermediate next, which temporarily stores it, waiting for the receiving node to be ready to receive it. Since packets are sent in bits, it is therefore not necessary to reserve a path during communication as different packets follow different paths and are later reassembled at the receiver’s end (Hekmat, n.

d). It should however be noted that other types of networks such as Global Area Networks (GAN) which is a model for developing specifications meant to support an communications across wireless LANs, Campus Area Networks (CANs) and Personal Area Networks (PANs) are coming up, but suh categories often tend to be superflous. 2. 2 Network Design For communication and exchange of data between any two nodes to occur, various underlying technologies must be in place and the interconnection is not as simplistic as it often appears.

The International Standards Organization (ISO) has a guide which is used as a reference model for network design and is popularly known as the Open Systems Interconnection (OSI) model. In this model, a layered archtecture of network is proposed, with each layer having a specified function, protocol and behaviour. It is against these layers that this research will discuss the various network infrustructure components. The various OSI model layers can be summarized as in the diagram that follow. The physical layer (Layer 1) transmits the electrical, light or other power through the communication medium such as cables.

It therefore defines such parameters as the cables to be used to send data and protocols. Data link layer (Layer 2) encodes and decodes the pieces of data into machine understable formats. Further, this layer checks for errors from the physical layer and does synchronization. The network layer(Layer 3) picks up the data from the data link layer and places it on the network, where the transport layer(Layer 4) provides end to end tranfer. The delivery depends on the session layer (Layer 5) which enhances connections between an application, initializes and terminates connections.

Layer 6 (Presentation layer) formats data to be sent over the network in addition to enhancing compatibility with the application layer. Lastly, layer 7(Application layer) is what supports user functions such reading an e–mail (Dave, 2008). The different layers are shown below. Fig. 3 Source: Dave 3. 0 Network Components The accomplishment of the various functions, and by various layers is however conceptual and various physical network components are used in practice. Such include cables, Network Adapter Cards, hubs, switching hubs, repeaters and bridges.

The two most popular cables in networking are the twisted pair (10BaseT) and the thin coaxial cable (10Base2). However, 10BaseT cables are the commonly used as they are thin, easy to use and are often supplied in custom lengths (NOSPINGroup, 2009). In addition they have connectors called RJ-45 connectors, that are synonymous to that of phone cord connectors. An example of an RJ-45 connector is shown below. Fig. 4 Source: NOSPINGroup A computer is connected to the network cabling with the help of Network Interface Card (NIC adapter).

The NIC adapter is often slotted into the machine’s expansion slots especially to enable speed critical applications such as databases or desktop video. However there are other devices called pocket adapters that connect a computer to the network via its printer port. Common NIC adapters take the form shown below. Fig. 5 Source: NOSPINGroup Having connected the different personal computers, a hub is then used to connect them centrally. It contains multiple ports and when a packet arrives through one port, it is copied over to all other ports.

This however does not change the destination address but rather just copies the data to all the nodes that are connected to the hub. A more advanced type of a hub is the switching hub that is able to treat each network card independently, thus not affecting their speeds. Faster connections can remain fast but still interact with lower connection speeds (NOSPINGroup, 2009). A switching hub is shown in the figure below. Fig. 6 Source: NOSPINGroup An entire network is formed by many small network segments that are joined together with the help of a bridge.

This is usually done in the data link layer (layer 2) of the OSI model. Bridges do not always copy traffic to all ports like hubs do, but rather, they identify which addresses are reachable through which ports. Once it has successfully associated a given address with a given port, it will send all traffic addressed to the identified address to that port only. However, it should be noted that bridges also send broadcasts to all the ports apart from the one the traffic was received from. A bridge representation is shown in the figure below. Fig. 7

Source: Network Hardware Components Data packets are usually forwarded across networks using headers and other techniques such as forwarding tables to determine the best path to forward the packets through. This is the work of a router, an electronic device that is more complex than a hub or a switch and often stands as the link between the internal private network and the rest of the world. Routers are placed at the network layer (Layer 3) of the Opens Systems Interconnection (OSI) model. Further, they are able to provide linkages between like and unlike media.

This is accomplished by examining the header of a given data packet and then making a decision on where in the next hop the packet should be sent to. Routers make use of preconfigured statistic routes, the status of their hardware interfaces as well as the set routing protocols to select the best route between any two networks, mainly LANs, WANs or still between a LAN and its Internet Service Provider (ISP). Advance in technology has seen Digital Subscriber Lines (DSLs) and modems for home use being integrated with routers to enable multiple home computers to access the internet (Network Hardware Components, 2007).

A typical router is shown in the figure below. Fig. 8 Source: Network Hardware Components As stated earlier in this research, networks notably MANs and WANs often span over many kilometers. The signal has to travel over many kilometers through a transmission medium thus undergoing degradation due to resistance and other effects. The signal therefore weakens as it travels and needs to be re-strengthened after a certain distance. This is the work performed by a device known as a repeater.

It is an electronic device that receives a signal and amplifies it, retransmitting it at a higher level or higher powers over an obstruction so as to enable it cover a longer distance. It should be noted that repeaters work with the actual physical signal and make no attempt to interpret it. Repeaters therefore operate on the physical layer (layer 1) of the OSI model (Network Hardware Components, 2007). A representation of a repeater is shown in the figure below. Fig. 9 Source: Network Hardware Components

The discussed components form a complete requirements list for a private network infrastructure that can now connect even to the internet. All nodes attached to the network are assigned identifiers called Internet Protocol (IP) addresses for unique identification. A complete network with the components in place is shown in the figure below. Fig. 10 Source: Network Hardware Components 4. 0 Application of Networks in Business The metaphor that a computer network, and more so the internet, is a superhighway that enables influx of people to their preferred locations of information and images is an apt one.

Computer networks implications to the society or at least to the portion of the society that can take advantage of technological innovations are deeply profound. The implication to that section of the economy that can actively and creatively make use computer networks to accomplish various business needs is even more momentous. The advance in technology that is enabling the sending and retrieval of information over networks for business purposes and their service delivery to the customer is no doubt raising businesses a notch higher.

Up until now, most businesses are using computers and computer technologies such as distributed systems that mimic the traditional physical stores or over the counter services, while enabling efficient and effective service delivery, that is not only timely but is also extremely accurate. According to an article by Anne Fischer on “Why use a network”, Anne reckons that connecting computers in a network lets people increase their efficiency through sharing files, resources and other facilities.

Consequently, networks have gained popularity in the recent past, so much that it has become a business norm, despite having appeared only in the past half century, primarily due to the arrival of the microcomputers that enabled users’ access to the same computer (Lent, 2004). A network enables sharing of resources. Through a network, different people are able to access and make use of the same file remotely. In addition, it prevents people from accidently creating different versions of the same information thus saving on memory storage. Moreover, any person who uses a computer is also likely to use a printer.

In a big organization, it would not be cost effective to have a printer for every working station. This problem is solved through the use of networks that make it possible for different work stations or even different offices to share the same printer (AllBusiness, 2010). Although a more expensive printer may be needed to handle the workload, it still makes more economic sense to use a network printer rather than connecting a printer to every work station. In business, collaboration especially in accomplishment of various tasks is often paramount.

However, it is usually hard for people to work together if no one knows what the other is doing. A network enhances collaboration among the various employees through file sharing as mentioned earlier, as well as using other services such as e-mails and other instant messaging tools. This way, workers are able to communicate quickly, effectively and easily as well as storing messages for future references and action. The most common means of sharing information especially in a corporate world is through the use of databases.

A university for example, deals with student details, both financial and academic. The two relate in that a university student must have met their financial obligation to qualify for academic services. Further, lecturers and professors need to post student grades to where students can access them. In such situations, keeping all these pieces of data in a database would make the university more efficient and effective, from where the different stakeholders can access what they need (AllBusiness, 2010). The other importance of networks is organization.

In the corporate world, organization especially among the various stake holders is important. Various stakeholders, with the help of interconnections, can be reached and networks make it possible even to arrange for meetings without having to constantly keep on checking on everyone’s schedules. Such applications often include other helpful features such as shared address books and to-do lists. Through such applications, network users can send each other everything ranging from memos, business quotations and informal hellos.

Advance in networks have also seen the development of technologies such as distributed systems that consist of multiple but autonomous computers that communicate with each other in order to achieve a common goal. Though the system appears as one coherent system to the user, the various functionalities are distributed across various networked machines. This has an advantage in that a complex task is shared up among the various machines thus enhancing load balancing within the system.

Further, it ensures scalability, openness and fault tolerance. Scalability refers to the ability of the networked system to accommodate more users as need be and without degradation in performance. Openness on the other hand ensures that more components can be added on to the network while fault tolerance ensures that a failure by one terminal does not mean total business collapse. Services of the failed terminal can still continue to be offered from other terminals as the functions are distributed (Coulouris, Dollimore, & Kindberg, 2005).

A typical example of distributed systems application is the banking systems explaining how one is able to withdraw cash from any Automated Teller Machines irrespective of their specific bank branch. Remote access of the organizational resources and greater mobility is also another major advantage that has emanated from networks and their use. Enhancing mobility while maintaining the same level of productivity has been achieved with users being able to access the same files, data and messages even when they are not in the office (AllBusiness, 2010).

This has given further impetus to businesses, where business transaction can be settled even with the use of handheld devices which make use wireless networks that are discussed next. 4. 1 Wireless networks Wireless communications are increasingly become more useful in more than voice calls. The increased and improved handsets and other mobile devices have improved transfers of data especially with the development of a range of sophisticated devices such as smart phones, hand-held PCs and Personal Digital Assistants (PDAs).

Different technologies such as Global Positioning System (GSM), Short Message Service (SMS), Wireless Application Protocol (WAP) and Global System for Mobile Communication (GSM) are used. In this mode of connection, different nodes are wirelessly connected. The original analog cellular systems are considered to be the first generation of mobile telephony and are often referred as 1G. These were deployed in the early 1980’s and it was not until 1990s that the second generations (2G) were deployed. The difference between the two is that the 1G used analog signaling while the 2G used digital signaling.

Years down the line, the third generation mobile telephony (3G) has emerged and is able to handle both data and voice applications. With these timelines, it is therefore certain to expect 4G mobile applications although their range of services may not be clear so far, but the various wireless technologies have impacted on businesses in various ways. With wireless networks, improved data communications have led to faster transfer of information with businesses as well as business partners transacting businesses easily. As an example, sales people have been able to remotely access stores and even check stock levels.

This has especially been the case considering that users can communicate even when on the move. They rarely loose touch with no extra cables and adapters being needed. It is worthwhile noting that wireless technologies have advanced to such levels such that it is possible to have chord less computer mouse and keyboards. With wireless technologies, office based workers can be networked without sitting at their dedicated machines and still continue to do productive work even while away from office. This has led to new styles of doing business and accomplishing official duties.

With home working, employees are able to execute their duties from home, while their organizations safe on office space and related cost (AllBusiness, 2010). Lastly Networks, whether wired or wireless have greatly impacted on education as well as e-businesses. As stated at the beginning, the aim of the first computer networks was to aid in research, mainly through linking various university and research institutions and therefore enhancing collaboration among researchers. Up to date, education still continues to be one of the areas where computer networks are greatly applied.

Long distance learning where a learner registers with a higher institution makes a good example. Such a learner is able to get all the learning material online and even collaborate with other scholars for purposes of discussions. In some instances, even examinations are administered online without having to attend any class that could even be located oversees. E-business has also benefited greatly from networks. People can now compare prices, place orders and even receive their supplies at the comfort of their desks thanks to computers and computer networks.

The concept of E-commerce through the internet has become common and even reduced the world into a global village. Even through a mobile device such as a web-enabled phone, it is now possible to transact business online with other online merchants all at click of a button. However, losses resulting from network failures can be serious and even detrimental to the business. As such, a network user should back up their data regularly, and a network helps one do exactly this back up (AllBusiness, 2010). This is done mainly through use of offsite servers or other backup systems.

Other network securities are addressed using technologies such as firewalls and data encryption technologies but in conclusion, the benefits accruing from computer networks are numerous and can not be emphasized more. 5. 0 Conclusion A critical evaluation of the mileage covered in technology, and more so in computer networks and connectivity reveals a fast paced growth, and neither has this technology reached the epic. Through various network components, it is possible to set up a network that can either be private or public depending on the technological needs of the individual or the business.

With more advancement in technology, it is nowadays possible to set up wireless networks that are faster in data transfers and enhance mobility. Whichever the type of connection, that both businesses and individuals have benefited greatly from computer networks is no doubt. Although network security is still a challenge, taking measures can help, and the future of the network technologies look bright. References AllBusiness. (2010). Why You Need a Computer Network. Retrieved July 6, 2010, from http://www. allbusiness.

com/technology/computer-networking/994-1. html Bell, M. (n. d). Inventors of the Modern Computer. Retrieved July 5, 2010, from http://inventors. about. com/library/weekly/aa091598. htm Coulouris, G. F. , Dollimore, J. , & Kindberg, T. (2005). Distributed systems: concepts and design. Boston: Addison-Wesley. Dave. (2008). CCNA Crash Course. Retrieved July 5, 2010, from http://davestechsupport. com/blog/2008/03/ Hekmat, S. (n. d). Communication Networks. Retrieved July 5, 2010, from www. pragsoft. com/books/CommNetwork Introduction to Computer Networks.

(n. d). Retrieved July 5, 2010, from http://www. functionx. com/networking/Lesson01. htm Lent, A. F. (2004). Why use a network? Retrieved July 6, 2010, from http://www. atarimagazines. com/compute/issue162/63_Why_use_a_network. php Network Hardware Components. (2007). Retrieved July 6, 2010, from http://mylovedreams. blogspot. com/ NOSPINGroup. (2009). Guide to Network Components. Retrieved July 5, 2010, from http://www. freepctech. com/pc/002/networks002. shtml Sunshine, C. A. (1989). Computer network architectures and protocols. New York: Plenum Press.