BUSINESS DATA COMMUNICATION AND SECURITY, Assignments of Computer Networks

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BUSINESS DATA COMMUNICATION AND SECURITY

Assignment 1

Patrick Brijraj

1. What is an application-layer message? A transport-layer segment? A network layer datagram? A link-layer frame? Elaborate on your answers. Application Layer Extrapolating from the authors (Vasudevan, Subashri & Kothari, 2015, p.32),concerning the application layer, one can see that on the OSI model the application is on the highest level and is closest to the end user for the purposes of operability of the computer on a network, beneath it are several other layers in which messages are being passed on with great complexities. On this layer is where all software application resides on, to which instructions sets in the form of protocols are given to computers from a client user perspective requested information which in turn will relay to lower levels on the OSI model for the purpose of transmitting data signals to a target system called the server that will respond. Typical example of first line application would be the internet browser, here the users frequently use the HTTP protocol, which is intrinsically a get command which the network understands. Further network application type instruction sets are FTP a (File Transfer Protocol), SSH (Secure Shell), SFTP (Secure FTP), Telnet, RDP (Remote Desktop Protocol) depending on specific protocol needs, each request would generate different outcomes, from data sharing, transfer, or access in to a machine. Transport Layer The authors Vasudevan et al. (2015, p. 30 - 31), highlights that on the fourth layer there are two protocols available a Transmission Control Protocol (TCP) and a User Datagram Protocol (UDP) found on the Transport Layer. The Transport layer essentially is responsible for the verification and the integrity of the data feed during the end to end transmission in comparison to the lower layers that may drop packets. The author Vasudevan et al. (2015, p. 30-31), goes on to solidify the process in that the, “Transport layer makes sure that it establishes, maintains and terminates the connections after transfer of data is complete”.

control, error notification and topology. It acts as a mediator between the network and physical layers. This layer is further broken into two sub layers. Media Access Control layer (MAC) and Link Logic Control layer (LLC). Media Access Control Layer The author defines the purpose of the MAC layer in operation in that it, provides regulated access to the network medium. If there are lot of stations connected to a same medium (channel), identification of the stations is still done successfully. This identification goes easier due to the MAC address. Since the MAC address is burnt into the ROM of interface cards it is not changeable and it remains unique. In short, this layer controls how a computer on the network gains access to the data and permission to transmit it, Vasudevan et al. (2015, p. 30- 31). Link Logic Control Layer The author also defines the purpose of the Link Logic Control layer in operation in that it, LLC provides enormous support for the flow control and error checking. Also, this sequences the control bits. LLC sits over the MAC layer. The devices that operate on layer 2 are very important for a network to be up and active. Bridges, Switches operate in this layer and they make sure that communication is uplifted, Vasudevan et al. (2015, p. 30-31).

2. Name the advantages of optical fiber over twisted-pair and coaxial cable. Please elaborate on your answer. According to authors, Forouzan; Leon-Garcia; Tanenbaum (as cited in Kelechi, n.d., p. 2 - 6 ), explained that telephone companies over the years have invested heavily into the fiber optic infrastructures for its high‐speed connection. Fiber Optics, it is known as the most sophisticated cables used in long distance network connection. Transmission is done through light ray signal transmission rather than electrical signal. It has inner core, surrounded by cladding, of glass that conducts light. Cladding is a layer of glass material that reflects light back into the core. Each fiber is surrounded by plastic sheath. Twisted Pair consists of two insulated copper wires arranged in a regular spiral pattern. Can be used to transmit both analog and digital transmission. Is limited in distance, bandwidth and data rate. The attenuation for it, is a very strong function of frequency. Unshielded twisted pair , Inexpensive, easiest to install but suffers from external interference example ordinary telephone wire. Shielded twisted pair, Metal braid or sheathing that reduces interference – Reduces noise, more expensive, harder to handle because its thick and heavy, easy to install with increase speed. Previously coaxial cables were a major role player used within the digital telephone network industry and was able to carry up to 600 Mbps of digital data. Coaxial Cable consists of the following layers in its construction, copper conductor, insulation layer of plastic foam, second conductor of shield of wire mesh tube or metallic foil, outer jacket of tough plastic and can be used for longer distances and support more stations on a shared line than twisted pair. However, the optic fiber solution proved to be faster than coaxial cable in that it, “serves as a backbone for many networks due to its wide bandwidth, is cost‐effective” and was the motivation for the transition onto the optic fiber network infrastructure. SONET network is an example of fiber optics. Notably a few cable TV companies still use a combination of coaxial cabling and fiber optics and could be based on client and user spend appetites, noting that these can be setup within a Local Area Network and Fast Ethernet System.

4. Explain and elaborate on the impact that communication network applications have had on business and everyday life. According to authors, Capron; McMahon (as cited in Kelechi, n.d., p. 24 - 28 ), Computer networks use electronic mail (e-mail) as the choice for most of the communication. By using networks, information can be sent to a larger audience in an extremely fast and efficient manner. A network with two clients and one server. a. Resource sharing (hardware, software, information, …) b. Providing communication medium (e-mail, videoconferencing) c. Doing business electronically (B2B, B2C, e-commerce) Networks for People Access to remote information e.g.: financial, shopping, customized newspapers, on-line digital library, WWW. Person-to-person communication email, video conference, newsgroup. Interactive entertainment VOD, interactive movies or TVs, game playing. According to the two authors books, Tanenbaum; Economides (as cited in Kelechi, n.d., p. 36 - 46), Communication network impacts the markets by offering products and services using an electronic platform which directly and indirectly creates jobs while generating revenue. It has a macro and micro impact to financial flow in a country, for business and the quality of life based on the supply and demand principle that are linked to systems, interconnected system and networks. Contributing to network externality in that the consumer’s perspective: is the added benefit a consumer gets as additional consumers join the same network or use the same product. The competitive firm’s perspective: A rival’s “network externality” is a barrier to entry. The Vertical Dimension: Network Effects and Complementary Goods, the benefit of a network or software platform may derive from the availability of complementary products. This is sometimes called an “indirect” network effect or “feedback effect.”

5. Why are standards important for protocols? Please elaborate. It creates a universally accepted way in which to build protocols, with less communication failures impacting business continuity as compared to the previously in house built protocols brought to market that may have created duplication if any because of similar protocols being created from different technology companies but may have differed in design, form and certain performance, which created the opportunity for a potential data mapping failures that made debugging, a challenge. During this time there was no central body controlling protocol standards. To resolve the inconsistency a reference model called Open Systems Interconnection (OSI) architecture and a formal body were created. In addition, the OSI was supported with a second standard called International Telecommunications Union (ITU), where a series of protocols based on the OSI architecture was published like the X.25, X.400, X.500, (Peterson & Davie, 2007, p. 55). The objective of standards in this context is to govern good communications and protocols for data related matters on the network to minimize predictable error through ensuring a certain network architectural pattern is abided and to promote transparency networking coding protocol practices, that any new protocol development is to be reviewed at a central body like the OSI and ITU for ratification for usage. Further having endorsed standards provides assurance with an international accepted way of doing transmissions. It may assist in a smoother resolution during network troubleshooting.

7. Compare the network topologies (Star, Bus and Ring). What capabilities and what limitations do they have? Please elaborate on your answer. According to two authors books, Capron; McMahon (as cited in Kelechi, n.d., p. 33 - 39) the following topologies types Star, Bus and Ring in respect to their capabilities, strengths and weaknesses where listed with further extrapolations provided, Star The outer circles could be anything from printers, laptops, devices and computers connected in a star configuration and is referred to as hosts. At the centre point circle is a hub, referred to as a node. The central hub from a high level is responsible for communication flows on the network. Which firms up the following findings from Capron; McMahon (as cited in Kelechi, n.d., p. 33 - 34) the following capabilities relating to the central hub within the star topologies achieving the following, “All messages routed through hub, Hub prevents collisions, Node failure – no effect on overall network, Hub failure – network fail”, (Kelechi, n.d., p. 33). The strengths and weaknesses can be summarized from authors, Capron; McMahon (as cited in Kelechi, n.d., p. 34) concerning strengths and weaknesses, Strengths as, “No single point of failure, Easier troubleshooting, Easy to design and implement, Changes are easy and No manual termination”, (Kelechi, n.d., p. 34). In addition, weaknesses as, “Expensive equipment (hubs), Single point of failure in case of hub failure, Requires termination, Too much cabling”. (Kelechi, n.d., p. 34).

Bus Based on the authors, Capron; McMahon (as cited in Kelechi, n.d., p. 37-38), the Bus network technical capability can be best described as: Single pathway in which message transmission occurs, All nodes and host are attached to the single network line, when collisions occurs it will resend , similar to the principle of parallel electrical circuit connection on the Bus top topology if there is communication signal or Node failure this will not have an effect on overall network, (Kelechi, n.d., p. 37). Further noting on their strength and weaknesses are as, strengths: From a spend point of view it is inexpensive, it is easy to design and implement such an infrastructure. The weaknesses, thou it is easy to implement when trying to isolate for trouble shooting it is difficult , following the principle of parallel electrical circuit connection a single point of failure would not jeopardize the entire eco‐system, however should there be a break in the wire it would mean no network as this governs the entire communication lines, (Kelechi, n.d., p. 38). Ring Based on the authors, Capron; McMahon (as cited in Kelechi, n.d., p. 35-36), the Ring network technical capability can be best described as, communication is transmitted around a circular connection in a one direction. There is no privacy during the passing of information through the nodes as it can see the data by establishing if it is addressed to this node and if it

APA Reference Benitez, C.J. (2019, May 8). How to Make Your Computer Bluetooth Capable. Retrieved from https://helpdeskgeek.com/networking/how-to-make-your-computer-bluetooth-capable/ Kelechi, A. (n.d). Basic concepts of connectivity and networking [PDF document]. Retrieved from lecture Notes Web site: https://zm-vle- uu.unicaf.org/pluginfile.php/81071/mod_folder/content/0/Reading%20Material%2 0 Week% 01.pdf?forcedownload= Kelechi, A. (n.d). Reading Material Week 3c [PDF document]. Retrieved from lecture Notes Web site: https://zm-vle- uu.unicaf.org/pluginfile.php/81077/mod_folder/content/0/Reading%20Material%2 0 Week% 03c.pdf?forcedownload= Kelechi, A. (n.d). Transmission Media [PDF document]. Retrieved from lecture Notes Web site : https://zm-vle- uu.unicaf.org/pluginfile.php/81071/mod_folder/content/0/Reading%20Material%20Week% d.pdf? Moss, C. (2019, September 9). The last places on Earth with no internet. The Telegraph. Retrieved from https://www.telegraph.co.uk/travel/lists/the-last-places-on-earth-with-no- internet/ Pérez, A. (2014). Network security. Retrieved from http://ebookcentral.proquest.com. Peterson, L. L., & Davie, B. S. (2007). Computer networks: A systems approach. Retrieved from http://ebookcentral.proquest.com Vasudevan, S. K., Subashri, V., & Kothari, D. (2015). Computer networking. Retrieved from http://ebookcentral.proquest.com