Networking knowledge

Office World News, Nov 2000 by Wood, Roxanne

The flow of data has become cyber sophisticated, and out reaches the expectations of business past. With just a click, networking has revolutionized human interaction, and developing business relationships. In information technology (IT), a network is a sequence of points linked by communication paths, which enhance the integration of data, voice, and video.

Businesses increase productivity, reduce expenses, and provide new capabilities by establishing a network. Sharing computing resources with other users is the most basic network feature. These resources include printers, CD-ROM drives, files, fax boards, Zip drives, tape backup drives, and on top of the list today Internet connections. Networks are even being made available to remote employees, whether at home or on the road.

Traditionally there are two types of network architecture: client/server and peer-to-peer. In a client/server architecture, each workstation or node is grouped either as a server or a client. Clients are usually common or desktop computers on which users run their every day applications. Servers are powerful computers that take care of drives, applications, databases, sharing files, etc. Client computers depend on servers for resources, such as directories, printers, files, and others. With a peer-topeer network, each workstation, sometimes called a node has equivalent importance, capabilities, and roles. They are generally easier to setup, not as costly, less secure, and may be harder to maintain.

The term wide area network (WAN) distinguishes a larger telecommunication structure from a local area network (LAN). A wide area network may be privately -owned or rented, however the term generally implies the incorporation of public (shared user) networks.

Most LAN systems installed today are called lOBase-T, which allows for speeds of data transmission of up to 10 Mbps. Recently however, Fast Ethernet 10OBase-T is being used. It supports the transfer of data at 10OMbps, as well as Gigabit Ethernet that supports data transfer rates of 100OMbps. Fast Ethernet is generally used at the backbone (A bigger transfer line that transports data brought together from smaller lines that interconnect with it) of the network, and on occasion continue to the desktops. At the backbone center of the network Gigabit Ethernet is used.

Ethernet is a technology that is used to implement most local area networks. It is a network protocol that was originally designed in 1976 by Xerox Corporation, DEC, and Intel. This protocol uses a star or bus topology. The cabling foundation for a common Ethernet LAN generally employs coaxial cable or twisted pair wires. Ethernet utilizes Carrier Sense Multiple Access with Collision Detection (CSMA/CD). This is an access procedure that controls simultaneous access from the network devices.

Moving right along, the- topology or configuration of a network pertains to the logical and physical arrangement of the devices of a computer system. It is common to have a combination of the basic topologies when designing a network. Deciding on the appropriate one is determined by specific business and network requirements.

The main local area network (LAN) topologies, commonly used in business are the bus, ring, and star.

Bus Topology-This a simple and inexpensive topology. It is practical for small LANs, providing basic connectivity. A single cable, called the, backbone or bus interconnects all network devices. Terminating resistors terminate the ends of the cable. A bus topology is used for Ethernet systems.

Ring Topology-These topologies are more expensive and more difficult to install, however they offer high- bandwidth (a measure of the range of frequencies a signal occupies) and can cover large distances. For example, it takes more bandwidth to download a photo in one second than it takes to download a page of text in one second. In a closed loop all networked devices are connected to one another. This is so that every device on the network is connected by the same signal path to two other devices, one on either side of each other. The ring allows for information to be transmitted in an unidirectional manner. Acting as a repeater, each device responds to and accepts packets addressed to it, and then moves on to forward the other packets downward to the next workstation.

Star Topology-Because star . topology is scaleable, easy to W 0 V-1install and manage, and most of all somewhat inexpensive they are dominant in today's LAN's. Another attractive feature about the star is that each device in this topology can get to the media independently. Although, potential bottleneck may occur because all of the devices are connected to a central hub.

Switched Topology.Somewhat like the star topology W W. is a new comer to this group. The structure is the same as the star, but instead of there being a central hub there is a switch. Switches improve performance in a LAN because each port, and the device that it connects to has its own specific bandwidth. Reducing the sharing of bandwidth increases the available bandwidth throughout the network.