The Connections In Physical Structure Information Technology Essay

The Connections In Physical Structure Information Technology EssayTwo or more(prenominal) computers affiliated together and they able to sh atomic number 18 the data and other resources, then we can say that the computers in the ne iirk.Networks are two typesradio receiver Network.Wired Network.Wireless Network wireless communication is one the fastest-growing technology. Connection using some telecommunication network whose inter connections amongst nodes is implemented with bring out the use of physical melody. wireless 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 pointMultipoint.Point to point The point to point provides a dedicated connection between two pulls .the entire capacity of the striking is reserved for transmission the data between those two devices only. Multipoint a multipoint connection is one inNetwo rk Topologies The end point 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. analysis situs of a network is re first appearance of the connection of all links and nodes together. There are basically 4 types of topologies are possibleBus regional anatomy In autobus topology using a single cable to connect all devices. One colossal cable acts as a backbone to link all the devices in a network. Devices are connected to the bus cable by toss 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 transform in to heat. Therefore, it become weaker as it travels tap to tap. Because of that we have a limited result 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 shout out star occupy. 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, surgical operation 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, nurture will go every time repeatedly. If one device does non work properly it gives an alarm. The alarm alerts the network operator to problem and where it happenAnyhow, 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 shutting off the break.Star Topology in a star topology from each one 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 some other, its sends the data to the hub which then relay the information to another connected deviceEach device needs only one link and one I/O port to connect it to any number of hubs. Thats 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. Be tween the hub and device. IfTree Topology tree network topology is a central node is connected to one or more other nodes that are one level pooh-pooh 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 mainadvantage of this topology is redundancy will be redjuced .Calcutation of how many nodes will connected to a mesh topologyIn 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 wor ds we can say that in a mesh topology , we need n(n-1)/2Suppose if we are connecting 15 nodes in a mesh topology, then the number of cables requiredN = n (n-1)/2 N = Number of cables= 15 (15 1)/2 n = Node= 15*14/2= 15*7= 105So the total number of cables required for connecting 15 nodes = 105.OSI MODELOSI 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 1970s. An open system is a set of protocols that allows any two different systems to communicate regardless of their fundamental 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 create as part of open system interconnection. In its most basic form it consists of seven separate but related layers.The OSI model is a shape 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 crossways the network.http//homepages.ius.edu/RWISMAN/B438/HTML/ch1_8.jpgPhysical layer physical layer coordinates the functions required to carry a bit stream over a physical link. It deals with mechanical and galvanic 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 accepted and passes it up. The physical layer is responsible for movements of individual bits from one node to next node.DATA LINK LAYERThe 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. D ata link layer performs the error check discards the frame if an error is detected. The responsibilities of the data link layer are Framing, fracture control, Flow control, Access control.NETWORK LAYERNetwork 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 synthetical 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 etceteraTRANSPORT LAYERTransport layer Manages source-to-destination message delivery in network.Provides reliable and sequential packet transfer through error recovery and feed control mechanismsProvides connectionless oriented data (packet) transfer.The main responsibilities of transport layer are service point addressing, segmentation and reassembly, connection control, flow control.SESSION LAYERIn some processes the physical, data link and network layers are not provide sufficientService. The session layer is network dialog controller.The session layer responsibilities are synchronization and dialog control.PRESENTATION LAYERThe 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 LAYERAPPLICATION 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 t ransfer and operations screening layer is responsible for providing service to the user.