The Connections In Physical Structure Information Technology Essay

The Connections In Physical Structure Information Technology Essay Two or more computers connected together and they able to share the data and other resources, then we can say that the computers in the network. Networks are two types Wireless Network. Wired Network. Wireless Network: wireless communication is one the fastest-growing technology. Connection using some telecommunication network whose inter connections between nodes is implemented without the use of physical cable. Radio waves are used to transmit the data between computes. Wired connection: wired connection means connection through a physical cable (back bone). There are two types of connections in physical structure. Point to point Multipoint. Point to point: The point to point provides a dedicated connection between two devices .the entire capacity of the link is reserved for transmission the data between those two devices only. Multipoint: a multipoint connection is one in Network Topologies: The term topology refers to the way in which a network is laid out. Two are more computers connected through a cable to a link; two are more links from topology. Topology of a network is representation of the connection of all links and nodes together. There are basically 4 types of topologies are possible Bus Topology: In bus topology using a single cable to connect all devices. One long cable acts as a backbone to link all the devices in a network. Devices are connected to the bus cable by drop lines and taps. A drop line is a connection running between the systems/nodes and main cable. A tap is a connector that either splices into main cable or punctures the sheathing of a cable to create a contact with the metallic core. As a signal travel along the cable, some of its energy is transformed in to heat. Therefore, it become weaker as it travels tap to tap. Because of that we have a limited number of taps. And have to maintain proper distance between those taps. The advantage of bus topology includes ease of installation. The cable which is used as a backbone is laid along the most sufficient path, and then connected to the nodes by drop lines of various lengths. Because of that, a bus uses the less hardware compared to other topologies like ring star mesh. The main advantage of this network is redundancy will be eliminated. The disadvantage of this network is it will be helpful if we have a limited number of devices. If more than few dozen computers will be added to the cable, performance will become low. If cable fails, the entire network becomes unusable. Ring Topology: In a ring network, every system will connect exactly with the two neighbors for communication purpose. All messages travel through a ring in the same direction (clock wise or anticlockwise). If any cable or device breaks the loop and can take down the entire network. A ring is relatively easy to install. To add or delete a device we require only two connections. Generally in the ring network, information will go every time repeatedly. If one device does not working properly it gives an alarm. The alarm alerts the network operator to problem and where it happen Anyhow, unidirectional traffic can be a disadvantage. In a simple ring network a brake in the ring will disable the entire network. This problem will be achieved by switch cable of closing off the break. Star Topology: in a star topology each device will connect to a central hub. The devices are not directly connected with each other. The hub acts like a central server, if one device wants to send the data to another, its sends the data to the hub which then relay the information to another connected device Each device needs only one link and one I/O port to connect it to any number of hubs. Thatà ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬Ãƒ ¢Ã¢â‚¬Å¾Ã‚ ¢s why it is very is to install and reconfigure. Less cable is needed to configure the star topology .and additions moves and deletions are very easy. Between the hub and device. If Tree Topology: tree network topology is a central node is connected to one or more other nodes that are one level lower in the hierarchy. It is combination of the bus and the Star Topologies. The tree like structure will allows you to have many servers on the network and you can branch out the network in many ways. Levant systems in their own network and yet connect to the big network in some way. Mesh Topology: In mesh topology every device has a direct link to all devices in the network. If a device wants some data information will pass between those only directly, the main advantage of this topology is redundancy will be redjuced . Calcutation of how many nodes will connected to a mesh topology: In mesh each node must connected with another nodes (ie node 1 will connect to the n-1 nodes). We need n(n-1) physical links.however, If each physical link allows communication in both dirrections (duplex mode). We can devide the number of links by 2. In other words we can say that in a mesh topology , we need n(n-1)/2 Suppose if we are connecting 15 nodes in a mesh topology, then the number of cables required; N = n (n-1)/2 N = Number of cables = 15 (15 à ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬ 1)/2 n = Node = 15*14/2 = 15*7 = 105 So the total number of cables required for connecting 15 nodes = 105. OSI MODEL: OSI model is established in 1947, (Open System Interconnection Reference Model) That covers all the aspect of network communications is the open system interconnection model. It was first introduced in 1970à ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬Ãƒ ¢Ã¢â‚¬Å¾Ã‚ ¢s. An open system is a set of protocols that allows any two different systems to communicate regardless of their underlying architecture. The purpose of OSI model is to show how a facility communication between the systems without changing their logic of understanding and designing a network architecture that is flexible, and transferable. It is developed as part of open system interconnection. In its most basic form it consists of seven separate but related layers. The OSI model is a layered framework for design of network systems that allows communication between all types of computer systems. It consists of seven layers, each of which defines a part of the process of moving information across the network. http://homepages.ius.edu/RWISMAN/B438/HTML/ch1_8.jpg Physical layer: physical layer coordinates the functions required to carry a bit stream over a physical link. It deals with mechanical and electrical specifications of interface and transmission medium. This layer deals with the physical devices of the media being used to transmit the information. The physical layer notifies the data link layer that a frame has been received and passes it up. The physical layer is responsible for movements of individual bits from one node to next node. DATA LINK LAYER: The data link layer transforms the physical layer, a raw transmission facility to a reliable link. The data link layer deals with providing one or more data link connections between two or more network entities. Data link layer performs the error check discards the frame if an error is detected. The responsibilities of the data link layer are Framing, Error control, Flow control, Access control. NETWORK LAYER: Network layer is responsible for the source-to-destination delivery of a data, possible across multiple networks. The layer provides switching and routing facilities. Creating the logical circuits for transmitting the data from node to node. If two systems are connected to a same link, there is no need of network layer. If two systems are connected to different networks there is often required the network layer to complete the transmission between sources to destination. The other responsibilities of the network layer are logical addressing, routing etc. TRANSPORT LAYER: Transport layer Manages source-to-destination message delivery in network. Provides reliable and sequential packet transfer through error recovery and flow control mechanisms Provides connectionless oriented data (packet) transfer. The main responsibilities of transport layer are service point addressing, segmentation and reassembly, connection control, flow control. SESSION LAYER: In some processes the physical, data link and network layers are not provide sufficient Service. The session layer is network dialog controller. The session layer responsibilities are synchronization and dialog control. PRESENTATION LAYER: The presentation layer deals with the syntax and semantics of the information exchanged between two systems. It masks the differences of data formats between dissimilar systems. The presentation layer is responsible for translation, compression and encryption. Presentation layer will encodes and decodes data; encrypts and decrypts the data; compresses and decompresses data. APPLICATION LAYER: APPLICATION LAYER enables the user, access the network. Interface to user processes for communication and data transfer in network Provides standardized services such as virtual terminal, file and job transfer and operations application layer is responsible for providing service to the user.

The Advantages and Disadvantages of Globalization

Globalization is such a commonly used term in the twentiethcentury. It simply means that the world has become integrated economically, socially, politically and culturally through the advances of technology, transportation and communication. It is undeniable to say that globalization has resulted in both positive and negative effects which must be addressed accordingly. To begin with, globalization has contributed to the worlds economies in many beneficial ways. The advances in science and technology have allowed businesses to easily cross over territorial boundary lines. Consequently, companies tend to become more productive, competitive thereby raising quality of goods, services and the worlds living standard. Secondly, several companies from the more developed countries have already ventured to establish foreign operations or branches to take advantage of the low cost of labor in the poorer countries. This kind of business activity will provide more influx of cash or investment funds into the less developed countries. However, one cannot deny the negative effects which havederived from globalization. One crucial social aspect is the risk and danger of epidemic diseases which can easily be spread as the mode transportation is easier and faster in todays advance society. This is evidenced in the recent birds flu disease which has infected most Asian countries over a short time frame. As large corporations invest or take over many off shore businesses, a modern form of colonization will also evolve which may pose certain power pressure on the local governments of the less developed countries. Unemployment rates in the more developed regions like Europe may also escalate as corporations choose to outsource cheaper work force from Asian countries. In conclusion. I like to reiterate that globalization is inevitable and we must urge individuals, companies and governments to use a more balanced approach by taking appropriate steps to deal with matters relating to the financial or economical gains verses the social, political or ecological concerns of the world.

The Theory Of The Philosophy - 1354 Words

Kantian is regarded as one of the perfect theories ever as far as an issue of morality is concerned. The theory is based on the concept of what is morally permissible by many. This means that the theory defines whether an action is morally right or wrong by evaluating how it is permissible by many in the society. Kant, a German philosopher argued that what is accepted in the society is what makes people’s lives good and that is what is moral. The theory states that even the simple things should not be ignored as far as they are accepted by universal law which is the majority people. The theory gives people the sole right to determine whether something is morally right or wrong. In the book, clones are mere ends because they were brought to†¦show more content†¦This shows that the society in the book viewed the act of cloning as an immoral act and thus according to Kantian theory, the act of cloning was morally wrong. Generally, cloning according to this theory is mora lly wrong because the majority in the society rejects the acts (Johnson 112). A right-based on moral theory, this is a theory that deals with rights of person when determining what is moral. Rights of person are usually the ones that determine the good life of a person and thus they are more related to molarity. The theory explains that very categories of individuals have their rights which they enjoy and they are not supposed to be compromised where these rights are based on what makes the lives of these people good. The theory further states that anything that compromises these rights is said to be immoral (Mackie 34). This theory can be applied directly to the book. To start with, clones as described earlier in the paper are humans. If they are humans, they have all the rights of human beings. For example, they have the right to make their own decisions, they have the right to live and they also have the right to have children. However, clones in the book have been denied or the above rights because Kathy and her partners cannot reproduce and they die before their age, they give out their organs against their will and they do what the school says, but not what they want. This shows that school has compromised their rights. In this case, the

Short Story - 794 Words

Billy Weaver was walking down the street after getting off the train when something in a window front caught his eye. If was as if he was a rat that smelled cheese and trying to sniff it out. The sign read, â€Å"Breakfest n’ Bed† It felt as if he’d been staring at the sign for hours. He walked up to the door and knocked on the door. Not after two seconds of knocking on the door it opened. There stood a woman, old, small, and looked like a normal grandmother. â€Å"Hello there,† the women said, â€Å" Please come in.† Billy was still stunned at how fast the door opened, but followed the women inside. â€Å"Please hang up your jacket and hat please.† Billy noticed that his jacket was the only one up on the coat hanger. He didn’t mind much of it and continued†¦show more content†¦Everyone needs to sign the guest book because it’s against the law if you don’t, and we don’t want the law involved, do we? â€Å"No ma’am.† The landlady nodded her head and left. Billy examined his room and then left to go sign in the book. As he was walking down the stairs, he passed a door that was cracked open just enough a small dog could fit in. Billy couldn’t resist and took a peek in. Billy saw a young man lying in his bed, but jumped back when he saw the man’s eyes staring at him as if he’s seen a ghost. Billy started walking down the stairs, but had the feeling of running. Once Billy got down the stairs he wandered around until he stumbled upon the guest book. Billy signed his name but saw two very familiar names above his. One was Gregory Temple, and the other was Christopher Mulholland. Billy could have sworn that he’d seen those names before, but couldn’t remember. â€Å"Please sit with me,† the landlady told Billy. Billy sat down next to the landlady wary of of his surroundings. â€Å"Would you like some tea?† â€Å"Umm†¦ no thank you, i’m quite alright,† Billy responded. â€Å"Did you sign the guest book, dear?† â€Å"Yes, yes I did ma’am,† â€Å"You seem worried, why do you seem worried,† the landlady inquired â€Å"Just a bit homesick that’s all. Well it’s getting quiet late I must be off to bed,† â€Å"Okay, dear,† the landlady said with a grin. 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