Computer Networks and Network Designs - Coursework Example

Computer Networks and Network Designs Name Tutor Course Date Abstract Computer networks are classified in a number of ways depending on scale, components as well as connection method. This paper will give an in-depth definition of these networks and where they should be best applied. IEEE defines standards for the different types of networks and topologies. The most common network used in organizations is the LAN as it only covers a small geographical areas. The WAN is most common among campuses and large organizations that extend up to more than one building for example a business park. The OSI and PCP/IP network models will be discussed in depth in this paper exploring the different layers of these models and their functions. Much emphasis will be given to the OSI network model as it is the most commonly used model. The final section in this paper will focus on an example of a network design between a main office and remote site and answer arising questions on what network has been used to setup and describe any limitations that may arise due to the choice of the network. Keywords (Networks, topology, network design) Table of Contents Abstract 2 Introduction 4 Components of a Network 4 Types of Networks 5 Local Area Network (LAN) 5 Applications of Local Area Networks 5 Metropolitan Area Network (MAN) 6 Wide Area Network (WAN) 6 Network models based on layers and the role of network standards 6 Network Layers 6 OSI Network Model Standard 7 Physical Layer 7 Data Link Layer 8 Network Layer 8 Transport Layer 8 Session Layer 8 Presentation Layer 9 Application Layer 9 TCP/IP Network Model Standard 9 The internet as a communications channel 10 Emerging data communication technologies 12 Network Design 13 Total number of machines to be networked 13 Physical network topology 14 Choice of topology, technology, advantages and disadvantages 14 Communication between the two sites and technologies available 16 Conclusion 16 References 17 Introduction Each of the previous three centuries was dominated by a single new innovation. The 18th century was the period of the mechanical systems going hand in hand with the Modern Revolution. The 19th century was the age of the steam motor. In the 20th century, the key innovation was data or information assembling, processing, and distribution. Among different advancements, we saw the establishment of global telephone networks, the innovation of radio and TV, the conception and remarkable development of the PC industry, the launching of satellites for communication, furthermore, of course, the Internet. As an aftereffect of fast technological advancement, these territories are quickly joining in the 21st century and the contrasts between gathering, transporting, storing, also, processing data are rapidly vanishing. Organizations that have hundreds of offices spread over a wide topographical territory routinely hope to be able to look at the current status of even their most remote station at the push of a button. As our capacity to collect, process, and disperse data develops, the interest regularly advanced data processing develops considerably faster. Components of a Network There are three common and most basic components of a data communications network: Server or host computer: This a machine that provides service to a client. It stores data or software that can be accessed by a client Client: This is a computer for example a PC that is connected to a network and is used to gain access to shared resources on the network. This falls in three major categories: terminal, workstation and special purpose terminals. Circuit: This is the pathway that allows transmission of messages. This can be twisted pair cable, fiber optic cable or even coaxial cable. Other circuits are such as microwave transmission [Ton02]. Types of Networks A computer network, otherwise known as a data network is a telecommunications network that allows data exchange between computers. In a computer network, devices that are networked pass data across connections and communicate with each other. The data transferred is transferred in form of packets. There are a number of communication networks and they are discussed below as follows: Local Area Network (LAN) Local Area Network, commonly known as LAN is the kind of network that is designed for smaller spaces such as offices, a group of buildings or an organization. Workstations and personal computers are connected via LANs. To achieve efficiency, the network designer will make use of the appropriate topology. LAN can be as simple as connecting two computers to exchange files or can be as complex as connecting systems (from computers to printers to fax machines and scanners) in an entire building to exchange information. Applications of Local Area Networks A single computer in a network can be centrally positioned to function as a server and the others as clients. Software can be installed on the server and it is shared by the clients. By connecting computers locally in a building in such a way that they can communicate with each other even without internet connection. Being able to share common resources such as printers, faxes and scanners are some of the common applications of LAN [Cla03] Metropolitan Area Network (MAN) It is an extended and bigger version of a Local Area Network. This type f network is designed in such a way that it extends over an entire city. The term is commonly used when the interconnection of computers in a city merges into a single large network. MANs are however smaller than Wide Area Networks and are usually characterized by connections that very high speed using a fiber optic cable or any other digital media. Wide Area Network (WAN) This a computer network that covers a relatively large geographical area. In the typical sense a WAN is made up of two or more LANs. Computers that are interconnected on a wide area network are most of the time connected via public networks for example a telephone system. Another way they can be connected is via leased lines or satellites. The largest WAN know is the internet. Network models based on layers and the role of network standards Network Layers The concept of layers in networking or rather systems administration was implemented to suit the changes in technology and innovation. Each layer of a particular system model may be in charge of an alternate capacity of the system. Every layer will pass information to and from a subsequent layer as data is processed. There are two major network models: The OSI network model standard and the TCP/IP or DOD network model standard [Moh14]. OSI Network Model Standard The layers in a network are arranged from a lower level to a higher level starting with the physical components which is the hardware to the higher levels. Below discussed are the layers in an OSI model network. Fig1. OSI Model Physical Layer This is the actual hardware. This is a layer that deals with the transmission of raw bits of data via a communication channel. In the design it is important to make sure that when one side of the network transmits 1 bit of data, the other side receives 1 bit and not 0. The physical layer portrays some kind of cabling framework as the transmission media. It additionally depicts the system topology and how the transmission media is to be conveyed. A few samples incorporate the transport, star, and ring topologies. Data Link Layer Puts information in frames and guarantees error free transmission. Likewise controls the timing of the system transmission. Includes type of frame, location or address, and information on error control. IEEE separated this layer into the following two sub-layers: Logical Link Control (LLC) and Media Access Control (MAC). Network Layer The system layer is in control of the operation of a sub-net, provision of routing, controlling congestion and accounting. The network layer gives provides two types of services: connection-less and connection oriented services. Transport Layer The main function of the transport layer is to acknowledge information or receive data from the session layer, divide it into smaller units, pass them to the network layer, and guarantee that the bits conveyed are the same as the bits transmitted without adjustment, loss or duplication. In the event that a mistake happens amid transmission, the transport layer must rectify it. Session Layer The session layer allows two or more people to communicate through what are referred to as sessions over a network. The applications on whichever end of the session can trade information or send parcels of data to another during the lifetime of a session. Presentation Layer The format of data transferred in the process of communications within the networks is catered for in this layer. It is responsible for the semantics as well as the syntax of the information that is transmitted. Application Layer This is the layer that appears at the top of the OSI model. It provide the following services: File Transfer, Access and Management (FTAM) Virtual Terminal (VT) Electronic Mail and Messaging Handling (MHS) Directory Services (DS) Common Management Information Protocol (CMIP) TCP/IP Network Model Standard Another famous network model is the TCP/IP Model and it has four layers- Link, Network, Transport and Application layers. It is important to note that these network models are important to consider when choosing a network model for use. The most critical concept to be understood in network models and layers is data encapsulation. Every layer in a network will either encapsulate data that is being streamed or include additional information or will manage handling of data [Moh14]. Fig2.TCP/IP Model The internet as a communications channel The internet is linking millions of people all over the world in a new “space” and transforming the way people think, the nature of people’s sexuality, the form of the communities that exist and defines people’s identities. The internet is vast and can be described in so many words for example: it is a library, a telephone, a shopping mall, a medium for broadcasting information and a public educational institution and so much more. The initial configuration of the internet included one component which was a mail network that was in electronic format. The initial development was for the sole purpose of acing as an alternative security network for the telephone in an instance where there is a nuclear attack. Its universal availability is the perfect adoption of two very important components: a universal and worldwide email network. This include a system of communication that works side-by-side with the World Wide Web which is made up of the largest library and information storage. The combining of the two components that is communication and information to come up with one system, has created room for the instant and worldwide availability to people of both personal as well as public information while giving them a chance to also contribute to both types of information [Aha14]. The internet has so many features. The first and foremost is that it is free. It is also medium that is not controlled allowing personal as well as virtual mobility. This is to mean that there are no laws, either institutional or governmental for browsing the communication lines on the internet. It also enables co-presence of people in both the physical and the virtual spaces at the same time. The emailing system allows for communication over long distance and making of calls or sending emails at no cost at all. The internet extends the spaces that people live in beyond their actual location. Cyberspace is divide into two major classes: information cyberspace and communications cyberspace. This section will focus on communications cyberspace. Communications cyberspace basically refers to the cyberspace of people who communicate with each other through the many different channels of communication. For example, video communications which involves the transmission of real space that is the background of the parties that are communicating plus images of themselves. Another example is the electronic or rather the invisible space of communication which is in the non-video format. This caters for emails, faxes, short message service and even audio telephone calls. This communications cyber space can be shared in many ways. First, it can be shared by smaller groups. Secondly, it can be accessed by larger groups through social networking sites for example blogs or other platforms for networking such as Myspace, Facebook, and Twitter. Most of this information is not recorded and if so, it is only used by the parties that are communicating. The initial access to the internet involved preparations to access a computer and a limited time session for access. However, emerging technologies such as broadband for desktops as well as mobile broadband for the laptops and smartphones have made the internet available to so many people. The internet in itself has become the heart of the people and takes up an integral part of the world. Organization are now switching from the physical to the virtual world and over time in the coming years, this will be a virtual world because of the internet. Emerging data communication technologies There have been great advancements in the field of information technology in the past few years. In this section, we will highlight the emerging technologies with specific reference to Wireless Local Area Networks (WLANs). The IEEE 802.11 gives a description of the WLANs which provides a faster access speed with each generation. The initial wireless stations could only provide speed of up to 1 Mbps but in the recent past these stations provided up to 1300Mbps. The main problem that is associated with the wireless is security. Anyone who has a radio receiver can be able to eavesdrop in a WLAN and at the same time, anyone with a transmitter can be able to send a signal to a WLAN. The IEEE standard for this that is 802.11 provides a Wireless Equivalent Privacy (WEP) that acts as a mechanism for confidentiality however, it is not foolproof [Sal04]. Another emerging technology in data communications is the Bluetooth. The problem with making use of this wireless technology is that fact that it is limited in physical range as well as bandwidth. This is a technology that has been developed to connect various devices that are wireless such as a PDA and a laptop or a cellphone. The global demand for broadband technologies has led to the existence and installation of fiber optics all over the world. The adoption of the DWDM-Dense Wavelength Division Multiplexing, the capacity of carrying information in fiber networks has massively increased. Network Design The design will comprise of a main site and a remote site all interconnected. At the heart of the network architecture there is a dynamic routing and switching network. The services that are used within the organization are operating on this network. Fig3. Network Design Total number of machines to be networked Assuming that the main site has about 50 workstations on different floors. Every floor in the organization has a central printer and scanner that services it. The remote site is just one single floor with not more than 10 workstations, a single printer. To be able to have access to the main site, there is an intranet that has been set up to ease communication between the main site and the remote site. The workstations in the remote site have access to one server that is connected to the intranet. Physical network topology In a connection such as this, one cannot make use of only one type of topology because there are different layers of connection as well as access. Consider the main site. Machines on a particular floor can be connected using bus topology. For example, if a particular floor houses only the IT or finance department, they will be connected via a single backbone. This will ease communication between the members of that particular department, enhance sharing of files and media and simplify communication. The network technologies that are considered for this kind of topology are 10Base-2 known as “ThinNet” and 10Base-5 commonly known as “ThickNet” (Anandalingam & Raghavan, 2003). Considering that every floor has a single printer and scanner, the star topology will be used to connect the workstations directly to the printer or scanner. This will enable users to print directly or scan directly from the printer onto their systems. The devices will connect to the printer hub using and Un-shielded Twisted Pair Ethernet. Start topology will make use of the IEEE 802.15.4. All the nodes on the network will connect to one central PAN coordinator. In as much as the FFDs are in range of each other, they are not allowed to communicate with each other if not the main node. Choice of topology, technology, advantages and disadvantages The choice of topology presents several advantages. Considering the bus topology makes it easy for installation for the fact that the main site is relatively large. Not much cabling is required but make it effective and high performing, this topology will be restricted to individual floors. The choice of star topology for access to resources such as scanner and printer, will ensure that failure of one workstation on the network does not affect the entire network. Failure of the printer or scanner however will mean that the entire floor network is affected and this is when interconnecting floor resources becomes handy. Fig4. Star Topology With the use of wireless devices such as the printers, it will make the network much more efficient. For example, one can use a wireless device such as the mobile to print without necessarily having to be configured on the organization network. Wireless devices such as laptops especially the personal laptops for members of the organization make use of the Virtual Private Network to access the resources of the organization. The virtual private network has its restrictions that will ensure the safety of documents and information of the organization. With the virtual private network, the employees can have access to files even in the comfort of their homes. This means that there is mobility of resources making the work more efficient. Communication between the two sites and technologies available The two sites will communicate with the use of the intranet. With the intranet, the HQ site can share applications, resources and information with one single license. The intranet makes the network cost effective and creates a single platform where information can be shared. The disadvantage however is that in cases where the intranet is down, the filed office or remote site has no way to communicate with the main site. Common applications will be posted on the intranet and they can be accessed by the remote site from there. Additionally, with the common intranet, there exists a common server and database. That is, the information about every machine or workstation on the network is stored on a central database. This makes it easier for the main site to deploy application on the machines on the network including the remote site. The existence of a server at the remote site enables it to create their own database and store their information this is a backup countermeasure that will make sure that they are secure just in case there is a problem with the main site. For example, if a server in the HQ crushes, they still have a backup of their information and can still have access to some resources though limited. Conclusion The three most important components of a network are a server, client and circuit. Depending on the size of the organization or the purpose, one is at liberty to choose the type of network to make use of. In many cases, organizations make use of hybrid topology to achieve maximum results and efficiency. The intranet has become very useful in the recent past among organizations that have more than one office as it helps with the deployment of applications, sharing of files and information and generally easing the access to files and applications when out of office. Wireless networks have become increasingly popular; from wireless printers to scanners and all that is required is compatibility. Organizations therefore choose what best suits their needs, communicate to their service providers and get it configured. References Ton02: , (Kenyon, 2002), Cla03: , (Clark, 2003), Moh14: , (Alani, 2014), Aha14: , (Kelleman, 2014), Sal04: , (Salgar, 2004), Read More