networking: Ever since the days of the Pony Express, people have lookedto getting information, whether personal or business, to its intended receiveras soon as possible. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-Category:CHOOSE ONEPaper Title:Text:networkingEver since the days of the Pony Express, people have looked to gettinginformation, whether personal or business, to its intended receiver as soon aspossible. The computer has evolved as a communications super-tool, enablingpeople to do just that. Networking has given individuals the power to transferideas, reports, and files quickly and efficiently. Networks also grant the powerto business professionals and families to conference with voice and video fromtheir individual offices or homes.
These abilities have made networkinginvaluable to many people in many different areas; however, networking can belimited to a small geographic region or even a single building and still havetremendous benefits. A Local Area Network (LAN) is a network of interconnectedworkstations sharing the resources of a single processor or server within arelatively small geographic area. LANs can be found in offices, schools,throughout whole buildings, and even dispersed throughout several buildings. Throughout these local networks, people are able to share files of information,communicate, and connect different departments to maximize efficiency.
A LAN iscomprised of several pieces of hardware that enable connectivity of the network;these include network interface cards, servers, bridges, repeaters, and hubs. ALAN can be comprised of all of these parts and more, but can also be constructedof less hardware. The hardware components of a specific network depend on theneeds of the network. A network interface card physically connects a computer toa transmission medium used on a network and controls the flow of informationfrom the computer to the network.
A network interface card has its own uniquehardware address that is embedded upon its manufacturing. The hardware addressis used to identify each NIC when information is being sent or received over anetwork. These cards are installed directly into the expansions slots of acomputer and in the case of portable computers require a specialized devicecalled a network adapter. Network interface cards have ports that are used toconnect the card to the transmission medium used throughout the network.
Different types of cards are designed to accept a certain type of transmissionmedium or network cable, which in turn determines the amount of information andthe speed at which that information can be sent. The NIC also contains atransceiver, which converts the computer output signal into a signal that can betransmitted over cable. In some instances a network interface card may alsocontain a boot chip, which enables a drive-less computer to access a network. Different cards are designed for different purposes, one type of card can beused by a client workstation solely to connect that computer to a network, whileothers are used by network servers that are specifically designed to transferlarge amounts of information. A hub is a device used to concentrate and organizenetwork wiring.
There are two basic types of hubs, active and passive. A passivehub is simply a device that allows wiring connections in an orderly way. Itrequires no power, and does no processing or regeneration of the traffic comingthrough it. Another type of hub is an active hub, which contains circuitry thatcan filter, amplify and control the traffic going through it. Hubs may alsocontain additional utilities, such as bridging, manageability, and repeaters.
Active hubs are based on an extension of the network repeater. It does this byaccepting network traffic on its input side, and then amplifying the signal onits output, allowing it to travel farther. A hub is a multi-port repeater. Physically, it appears as a box with one input port and a number of output portsthat are typically wired to end-user workstation connections, although serversand other devices can be attached as well. Signals on any port are transmittedto all the other ports. Although a basic hub provides a way to organize cablewiring, it does not segment or organize network traffic in any way.
Hubs areused in the design and implementation of a coherent and easily managed networkcabling system. In a typical design, a company may run cabling from a wall platein each user’s cubicle to a central wiring closet on each floor of the building. These cables, known as station drops are each connected to a port on the wiringhub. The hubs on each floor are then connected to the network backbone, whichruns from floor to floor in each wiring closet. This divides the network intological and physical groupings that simplifies troubleshooting and networkgrowth. Because of the signal boosting performed by the hub, it can also extendthe physical scope of the network.
A recent innovation is the concept of theswitching hub. A switching hub basically bridges the output as well as the inputports on the hub. With this arrangement, traffic from a port will not pass tothe hub unless it needs to access a different port than it came in on. If itneeds to pass across the hub to reach its destination, it only passes betweenthe two ports it needs, and is isolated from the rest of the ports. This cutsdown unnecessary traffic on all network segments attached to the hub, improvingthe capacity and speed of the network. A bridge is used to interconnect two ormore similar LANs or to divide a large network into smaller more manageableones.
Splitting of a large network with a bridge increases the efficiency of thenetwork and reduces the chances of an overload. A bridge is able to increaseeffectiveness of two connected networks because it only passes information isbound for the “far side” of the bridge if necessary. There are twotypes of bridges, simple and learning. A simple bridge receives packets ofinformation and retransmits them to all ports until that packet reaches thecorrect one. A learning bridge reads, stores, and learns the addresses of eachcomputer on the network.
The learning bridge then constructs a table toefficiently route packets to the correct port, without wasting resources sendingeach packet to every port. If a packet comes through the bridge intended for adestination not recorded on the bridging table, the bridge sends the packet outto all ports and records the accepting destination. A repeater is a device thatextends the length of transmission media over which network information ispassed. A repeater accepts network input, amplifies the signal, and retransmitsthe information.
Repeaters are especially useful when a network is cabledthroughout a large building, over several floors. They are also able to filterout interference or distortion before retransmission, but are unable to operateefficiently when attempting to transfer huge amounts of information. A repeateris a simple device contained in a stand alone box or within a hub-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-