Networks classification Essay Example for Free

Networks classification Essay In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software. Networking software applications are available to manage and monitor networks of all sizes, from the smallest home networks to the largest enterprise networks. Networks classification 1. Local Area Networks (LANs): These connect over a relatively small geographical are, typically connecting computers within a single office or building. In most cases they connect to a common electronic connection- commonly known as a network backbone. LANs can connect to other networks either directly or through a WAN or MAN. Most LANs connect workstations and personal computers. 2. Metropolitan Area Networks (MANs): These connect networks around a town or city. Short for Metropolitan Area Network, a data network designed for a town or city. In terms of geographic breadth, MANs are larger than local-area networks (LANs), but smaller than wide-area networks (WANs). An example of a Man is the Eastman (Edinburgh and Stirling MAN) network that connects universities and colleges. 3. Wide Area Networks (WANs) : These connect networks over a large geographical area, such as between different buildings, towns or even countries. 4. A campus area network (CAN) is a computer network made up of an interconnection of LANs within a limited geographical area. In the case of a university campus-based campus network, the network is likely to link a variety of campus buildings including, for example, academic colleges or departments, the university library, and student residence halls. 5. A personal area network (PAN) is a computer network used for communication among computer and different information technological devices close to one person. Some examples of devices that are used in a PAN are personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. A PAN may include wired and wireless devices. The reach of a PAN typically extends to 10 meters Topology Network topology is the arrangement of the various elements (links, nodes, etc.) of a computer or biological network. Essentially, it is the topological structure of a network, and may be depicted physically or logically. There are two basic categories of network topologies: 1. Physical topology refers to the placement of the networks various components, including device location and cable installation, 2. logical topology shows how data flows within a network, regardless of its physical design. The study of network topology recognizes eight basic topologies: †¢ Point-to-point = the simplest topology is a permanent link between two endpoints. †¢ Bus = A linear bus topology consists of a main run of cable with a terminator at each end (See fig. 1). All nodes (file server, workstations, and peripherals) are connected to the linear cable. Advantages of a Linear Bus Topology †¢ Easy to connect a computer or peripheral to a linear bus. †¢ Requires less cable length than a star topology. Disadvantages of a Linear Bus Topology †¢ Entire network shuts down if there is a break in the main cable. †¢ Terminators are required at both ends of the backbone cable. †¢ Difficult to identify the problem if the entire network shuts down. †¢ Not meant to be used as a stand-alone solution in a large building. †¢ Star = A star topology is designed with each node (file server, workstations, and peripherals) connected directly to a central network hub, switch, or concentrator (See fig. 2). Data on a star network passes through the hub, switch, or concentrator before continuing to its destination. The hub, switch, or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow. This configuration is common with twisted pair cable; however, it can also be used with coaxial cable or fiber optic cable. Advantages of a Star Topology †¢ Easy to install and wire. †¢ No disruptions to the network when connecting or removing devices. †¢ Easy to detect faults and to remove parts. Disadvantages of a Star Topology †¢ Requires more cable length than a linear topology. †¢ If the hub, switch, or concentrator fails, nodes attached are disabled. †¢ More expensive than linear bus topologies because of the cost of the hubs, etc. †¢ Ring = A network topology that is set up in a circular fashion in which data travels around the ring in one direction and each device on the right acts as a repeater to keep the signal strong as it travels. Each device incorporates a receiver for the incoming signal and a transmitter to send the data on to the next device in the ring. The network is dependent on the ability of the signal to travel around the ring. When a device sends data, it must travel through each device on the ring until it reaches its destination. Every node is a critical link. †¢ Mesh = The value of fully meshed networks is proportional to the exponent of the number of subscribers, assuming that communicating groups of any two endpoints, up to and including all the endpoints Advantages of Mesh topology 1) Data can be transmitted from different devices simultaneously. This topology can withstand high traffic. 2) Even if one of the components fails there is always an alternative present. So data transfer doesn’t get affected. 3) Expansion and modification in topology can be done without disrupting other nodes. Disadvantages of Mesh topology 1) There are high chances of redundancy in many of the network connections. 2) Overall cost of this network is way too high as compared to other network topologies. 3) Set-up and maintenance of this topology is very difficult. Even administration of the network is tough. †¢ Tree = A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable (See fig. 3). Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs. Advantages of a Tree Topology †¢ Point-to-point wiring for individual segments. †¢ Supported by several hardware and software venders. Disadvantages of a Tree Topology †¢ Overall length of each segment is limited by the type of cabling used. †¢ If the backbone line breaks, the entire segment goes down. †¢ More difficult to configure and wire than other topologies. †¢ Hybrid = Hybrid networks use a combination of any two or more topologies in such a way that the resulting network does not exhibit one of the standard topologies (e.g., bus, star, ring, etc.). For example a tree network connected to a tree network is still a tree network topology. A hybrid topology is always produced when two different basic network topologies are connected. Two common examples for Hybrid network are: star, ring network and star bus network †¢ Daisy chain = Except for star-based networks, the easiest way to add more computers into a network is by daisy-chaining, or connecting each computer in series to the next. If a message is intended for a computer partway down the line, each system bounces it along in sequence until it reaches the destinati on. A daisy-chained network can take two basic forms: linear and ring. o The straight-through cables are used when connecting Data Terminating Equipment (DTE) to Data Communications Equipment (DCE), such as computers and routers to modems (gateways) or hubs (Ethernet Switches). The cross-over cables are used when connecting DTE to DTE, or DCE to DCE equipment; such as computer to computer, computer to router; or gateway to hub connections. The DTE equipment terminates the signal, while DCE equipment do not. †¢ RJ stands for Registered Jacks. These are used in telephone and data jack wiring registered with FCC. RJ-11 is a 6-position, 4-conductor jack used in telephone wiring, and RJ-45 is a 8-position, 8-conductor jack used in 10BaseT and 100BaseT Ethernet wiring. †¢ UTP stands for Unshielded Twisted Pair. It is the cabling system with one or more pairs of twisted insulated copper wires contained in a single sheath. It is the most widely used cabling system in telecommunications and data communications environment today.