Unit 9- Computer NetworkAssignment 1

ContentsTask 13Different type of network:31.LAN32.WAN43.MAN44.PAN4Topologies51.Ring52.Star53.Mesh54.Tree65.BUS6OSI and TCP/IP Layer model7Physical7Data link7Some layer 2 Protocol include8Ethernet 802.3:8Token-Ring 802.5:8Network9Protocols:9IP9Apple Talk9Transport9Protocol:9TCP9UDP9Session10Presentation10Application10FDDI:10Wireless technologies103G11Bluetooth11802.1111Infrared11Application layer protocols11DNS11DHCP11HTTP12POP12SMTP12Task 213Why different network standards and protocols are necessary13Task 313Peer-to-peer and client-server network13Peer-to-peer:13Benefits14Client-server:14Benefits14

Task 1Different type of network:There are different type of network based on their size of data transfer speed and their reach. 1. LAN- is known as Local Area network, it is a type of network that connects group of computer which all belongs to the same organisation. E.g. house, company. LAN connection can be very fast due to data traveling over a small geographic are, it can usually operate at speed of Giga bit.[endnoteRef:1]By expanding the definition of a LAN to the services that it provides, two different operating modes can be defined: [1: kioskea. ().Types of networks.Available: http://en.kioskea.net/contents/266-types-of-networks. Last accessed 25/09/2013.]

In a "peer-to-peer" network, in which communication is carried out from one computer to another, without a central computer, and where each computer has the same role. in a "client/server" environment, in which a central computer provides network services to users.

2. WAN is known as Wide Area Network, it connects LANs to one another over a wide range distance. The speed is determents on the cost of the connection such as quality of the cable and length of the cable. WANs can be choose the appropriate path for the data to reach a network node by using a router.

3. MAN- is known as Metropolitan area network, this connects LANs to one another over a wide range, for example your area where you live will be a WAN then your house would be a LAN and all the other house as well. This then connects to the WAN to be connected to the internet. A MAN is made from switches and routers to connected to one another using a high-speed line such as fibre optic cable

4. PAN Is known as Personal Area Network, it can be set up by person to transfer files like email, digital photo and music. You can use your mobile phone as a modem to allow other devices to be connected like a PDA, Laptop and mobile phone. Personal area network can be constructed with a cable or wireless, and USB, however it has a restriction range of less than 10 meters. PAN is a special type of LAN that support one person instead of a group.

Topologies1. Ring: this network is one of the easiest to use, it is simply for sending packages by using one wire. The message goes through all the computer till the destination, this has a disadvantage displays all the message on each computer which it travel before it gets to the destination.

2. Star: the star topology uses hub which all the computer is all connected to it, it is easy to install and use, however all data must pass through the hub.

3. Mesh: this type of topology is difficult than other topologies but its similar system, all the computers are connected with each other on the network. The benefit from this is that if one computer fail/disconnected, the other computer still can be communicated, the data can be still be send to the right one.

4. Tree: tree topology is combination of star and line topology, it contain 10 star topology in a tree, a star topology can contain up to 30 computers usually. They are connected to other star network using line topology.

5. BUS: in this network all the computers are connected to one cable, this is the cheapest and easy way of installing a small network, for example you can connect two or more computers in your home which is linked to a central cable know as a bus. This can allow the computers or devices to be communicated.

OSI and TCP/IP Layer model

In OSI model there are 7 type of player, this comes in stages. The first layer is:Physicalphysical layer is the first layer of the OSI (Open System Interconnection), this is because its where the transmission and receives raw bit stream. This is an important layer due to carrying the signal for all the other layers. It carries out the binary transmission, voltage levels and data rate, this layer also represents physical properties such as cables and network cards. The cable that the physical layer uses would be Coaxial and UTP. Coaxial cableUTP Cable Data link This layer is the second layer of the OSI model, in this layer it controls the communication between the network layer and the physical layer. The function on this layer is to get the data that it receives and divide into distinct frames that can be transmitted by the physical layer. The frames are groups of information which are bits it a way of sending data along with address information and error checking.

Some layer 2 Protocol include:Ethernet 802.3:Ethernet is a protocol which computers are connected to a cable which uses a method called CSMA/CD (Carrier Sense Multiple Access/collision Detection). This method works by each computer which is connected to the cable listens before it sends anything along the network. If the network is clear, the computer will send the signal, however if other computer is already transmitting on the network. The computer will have to wait until the line is clear. If two computer transmit at the same time, a collision will occur. Then the two computer will have to wait and send one by one. This protocol can transmit over wireless point, twisted pair, coaxial, or fibre optical cable at a speed of 10Mbps up to 1000Mbps. The Ethernet protocol allows for linear bus, star, or tree topologies.

Token-Ring 802.5:Token- ring Protocol is when all the computers are connected to each other and the signal travels from one computer to another in a ring motion. This protocol works by moving around the computer in a ring motion with an electronic token which passes through all the computer in the ring, the information is only transmitted when the token is held, if a computer does not have information to transmit, it simply passes on to the next workstation. The token ring protocol requires a star-wired ring, using twisted pair or fibre optical cable, the transmission speed of 4 Mbps or 16Mbps.

NetworkNetwork is the third layer of the OSI model, in this layer it involves in the Address, this determines the best path or routes that the data is travelling. There are three type of way which data can be routed to their destination. First, static rout which dont change. Second, static line only used by the sender and receiver. Third, send through network using changing paths in order to prevent hold-up. One of the main function is to allow two different networks using conflicting addressing schemes to be able to send data to each other. The equipments that is at this layer is a Router which uses IP address to route packets. Protocols:IP: Internet protocol is the method of sending data from one computer to another on the internet. IP address is the identity of a computer on the internet. When sending and receiving data from the internet it is divided in to small parts called packets. Each packets can be send in different routes across the internet, however each packets will come in different order. To put them back together Transmission Control Protocol (TCP) is used.

Apple Talk:Apple talk is protocol made for apple computer, it a Local Area Network communication which it can support up to 32 devices. The data transmission at speed of 230.4 Kbps, the radios of the divides can be up to 1000 feet apart.

TransportTransport is the fourth layer of the OSI model, it used to ensure that the data send from one computer arrives reliably. When the data arrives it is responsible for the coming packets into their original state and without errors. To ensure the data is delivery without any errors, the transport layer builds an error control mechanism provided by the network layer. This layer is also responsible for the flow control, which is the rate of transmission. It is determined on how fast the receiving computer can accept the data segments.Protocol:TCP: TCP protocol is when the sender and the receiver using a socket which determined by the IP address. The packets are tracked until the delivery is made to insure it had delivered to the receiver and if not it can be resent. It is a reliable protocol to be use, this is mostly used in secure website for example Emails.UDP: UDP protocol is unreliable because its not guaranteed that the packets will be delivered between the sender and receiver. Since there arent any way of tracking the packets, there are no way of asking the sender to retransmit because of an error. This protocol is commonly used in YouTube. Which the packets some in any order. SessionSession is the fifth layer of OSI model, it is responsible for creating communication between two nodes on the network. It opens and closes the communication link between the two. The session is refers to a connection for data exchange between two parties, this can allow data to be send in either direction at the same time or only one direction. When a large file is been transmission and the system crashes, checkpoint allows the system to start downloading at the last known checkpoint.

Presentation Presentation is the sixth layer of OSI model, its main objective is to translate between the application and the network. It translates the raw data into the form that the application layer can accept. Syntax layer is when the data is encrypts to be sent across the network which gives freedom from capabilitys problems. This layer also reduces the number of bits needed to send the packets of information. The data encryption and decryption is the security for the data. For example when receiving jpeg image it comes packets and the presentation layer will translate the raw data into the form that the application can accept.

ApplicationApplication is the seventh layer of OSI model, its role is to provide services that support the user to the software such as interface, file transfer, email, etc. in this layer there are many protocols are used to give the application access to the network. When transferring files, some computer store file names or represent text line differently, this layer takes care of the incompatibilities and allows good transfer between systems.

Network protocols and standardsNetwork protocols are rules for communication between computers on a network. The protocols include how they are accessed, topologies, and type of cables they use and the speed of the data transfer. FDDI:Fibre Distributed Data Interface Protocol is join two or more Local Area Network (LAN). To use this protocol it will need token-passing. There are two ring topology in FDDI, transmission occurs on one of the ring, if a break occurs the system will still move the information using the second ring to create a new complete ring. This protocol transmission speed is at 100Mps over a fibre optic cable.

Wireless technologiesCommunication channels between computers by radio waves or microwaves. Wireless networking is a more modern then wired networking which relies on copper and/or fiber optic cabling between network devices. It needs modems to send the signal to the receive. For example Wireless LANs or local area networks provide flexibility and reliability for business computer users.3GIt is the third generation of wireless technology. 3G is mostly used with mobile phones and handsets as a means to connect the phone to the Internet in order to make voice and video calls, to download and upload data and to surf the net. 3G network can has speed of up to 3Mps which can download 3minutes of Mp3 song in 15second. BluetoothIt is a device that allows you to exchange date from a short distance by radio frequency. Its normally found on a mobile phone or a computer. Bluetooth network can transmits signal up to 10 meters of distance. Bluetooth communication speed of 1 Mbps. 802.11 802.11 is wireless LAN and has speed of 1 or 2 Mbps, it transmission in the 2.4 GHz using two type of frequency, hopping spread spectrum and direct sequence spread spectrum. Infrared Infrared is a method of communication with other devices using a short range wireless signal. Infrared can transfer files and other data within the two devices. Its communication range is sort, placing two infrared devices within less than 5 meters of each other. [footnoteRef:1]IrDA-SIR (slow speed) infrared supporting data rates up to 115 Kbps [1: http://compnetworking.about.com/od/homenetworking/g/bldef_infrared.htm]

IrDA-MIR (medium speed) infrared supporting data rates up to 1.15 Mbps IrDA-FIR (fast speed) infrared supporting data rates up to 4 Mbps

Application layer protocols: DNS[footnoteRef:2]DNS is application layer that translate domain names in IP address, this is a protocol that automatically translate the name we type in in our web browser in to IP addresses of the web server you are entering. The reason that it translate to IP addresses is because domain name are in alphabetic, however the browser understand IP address. Example of IP address is 198.105.232.4 [2: http://compnetworking.about.com/cs/domainnamesystem/g/bldef_dns.htm]

DHCPDHCP is a communicate method used by devices such as router, computer or network adopter to request IP address from a server.[footnoteRef:3]Definition:DHCPallows a computer to join an IP-based network without having a pre-configured IP address. DHCP is a protocol that assigns unique IP addresses to devices, then releases and renews these addresses as devices leave and re-join the network.Internet service providers usually use DHCP to help customers join their networks with minimum setup effort required. Likewise, home network equipment likebroadband routersoffers DHCP support for added convenience in joining home computers tolocal area networks [3: http://compnetworking.about.com/cs/protocolsdhcp/g/bldef_dhcp.htm]

HTTPHyper Text Transfer Protocol is a protocol used by the World Wide Web, this is determent how the text are transferred. It also sees what action is needed by the web server and browser should take in order for the web server to direct the request web pages. Modern browsers doesnt required HTTP in front of the URL because its the default method of communication. The HTTP recovers the Web page from the World Wide Web by communicating with web browser to the web server.POPPop stands for Post Office Protocol, its job is to retrieve emails from email server. Most emails application use the POP protocol however, the newer email uses IMAP (internet Message access Protocol) SMTPSMTP is known as Simple Mail Transfer Protocol, this is used to allow software to transmit email over the internet. This only works for outgoing messages, most emails are designed to use SMTP for communication when sending email.

Task 2Why different network standards and protocols are necessary The reason that protocol are necessary because they are sets of rules which is used allow communicate between computer, if same protocols are used it can improve in data transfer. The most common used protocol is TCP/IP, they both have different objective, TCP (Transmission Control Protocol) and IP (Internet Protocol). [endnoteRef:2]An example of Protocol is when two people talking on the phone, one talks and other listens. Then they reverse, and the talkers becomes the listener. If both talk and both listens there are no data been exchanged. [2: http://answers.yahoo.com/question/index?qid=20080229131516AAhHb3b]

Different networks standards are needed because they all are different, they communicate differently. Networks are like languages, they all have different language, when communicating with other devices you will need to make sure that the device you are using has the same language as the device you are communicating, if the both device dont have the same language it will not understand the communication, therefore the network will not work to its standers. Network standards are also set of rules so that the hardware is compatible with other similar computer this is because if each company has its own protocol standards and this will not allow it to talk with other computer or devices. So network standards and protocols are need because they are what allows different company computers running different software to communicate with each other. Protocols and standers are what makes different computer with different components communicates with each other, this is why standards are introduced in to manufactures in terms of computer and the components. [endnoteRef:3]An example is if you and your neighbours were all using the same type of routers and all had wireless enabled with the WEP key not activated then you would have a problem. Its important to set different protocols so that you can identify which computers is using what and where it is. [3: http://answers.yahoo.com/question/index?qid=20080229131516AAhHb3b]

Task 3Peer-to-peer and client-server network Peer-to-peer:Peer-to-peer network is a network that has no central computer that acts as a client server, this means the computers are independent. Peer-to-peer network is found at home and other small business. Peer to Peer allows group of computer to be on the same network to connect each other and directly access files from one another, when Peer to Peer is used in Business, it can be a benefit for employees to share files without the expense of physically sharing files. To set up Peer to Peer network you will need networking program like Gnutella Net, this software is allows users to exchange all type of files. To share the files in the peer to peer network, the user will need to enter IP address of another computer in the same network, this will then make a one to one connection with both users which then, he/she can share files between them.

Benefits Peer-to-peer networks is easy to set up and you will not need special knowledge to operate because each users will not need to set their own permission as which file would like to share, and the network doesnt require network operating system. Peer-to-peer network is cheap to set up, you will not need an expensive server because each computers are used to reach the files. If one computer in peer-to-peer network fails to run, it will not disrupt the rest of the network. However, peer-to-peer has much as disadvantages, the files are stored on individual computer, this means that the files are not centrally organised and it will hard to locate if the user done not have filling system. The peer-to-peer does not have security other than permission and to login to the computer. The files cannot be centrally backed up.Client-server:Client server network is an online network which has a main computer that acts as a server, this computer then directs the network services to the other computer. It allows staff to store their works centrally, the client server will have all the shared files and other information saved on the computer. Client server are mainly used in large businesses because it many have different departments, each department can use a server to connect to each other. Its more secured then peer-to-peer network, you have assign passwords to own individual profiles so that nobody can access your document. As your work is on the server it easily to make a back0ip of it, in case you lost the work, it can be easily recovered. Benefits In Clients server network the shared data is controlled, all the files are stored in the central computer, it is also frequently backed-up and secured. However, the disadvantage of client server network is that the servers are expensive to buy and if a part of the network corrupts it can do a lot of disruption. I think that Bob and Bill should get Peer-to-peer network, because you will not need to spend any money on setting up or buying a central computer, however Bill has an old desktop which had no network capabilities. Bill will need to spend money to buy a Network Interface Card in order to connect the desktop to a network. Peer-to-peer network doesnt require any special knowledge of networking to set up and maintain. With this type of network they will be capable of playing games against each other due to sharing files and internet. When connecting a printer to peer-to-peer network they need to make sure that they connect the printer to the fast performing computer. Bill and Bob are able to share comics, films and music by setting up the permission which is the access to the files, this will determine who can access the file and who cant.

P.Jesugeevegan