Networking Essay, Research Paper
networking
Ever since the days of the Pony Express, people have looked to getting
information, whether personal or business, to its intended receiver as soon as
possible. The computer has evolved as a communications super-tool, enabling
people to do just that. Networking has given individuals the power to transfer
ideas, reports, and files quickly and efficiently. Networks also grant the power
to business professionals and families to conference with voice and video from
their individual offices or homes. These abilities have made networking
invaluable to many people in many different areas; however, networking can be
limited to a small geographic region or even a single building and still have
tremendous benefits. A Local Area Network (LAN) is a network of interconnected
workstations sharing the resources of a single processor or server within a
relatively 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 is
comprised of several pieces of hardware that enable connectivity of the network;
these include network interface cards, servers, bridges, repeaters, and hubs. A
LAN can be comprised of all of these parts and more, but can also be constructed
of less hardware. The hardware components of a specific network depend on the
needs of the network. A network interface card physically connects a computer to
a transmission medium used on a network and controls the flow of information
from the computer to the network. A network interface card has its own unique
hardware address that is embedded upon its manufacturing. The hardware address
is used to identify each NIC when information is being sent or received over a
network. These cards are installed directly into the expansions slots of a
computer and in the case of portable computers require a specialized device
called a network adapter. Network interface cards have ports that are used to
connect the card to the transmission medium used throughout the network.
Different types of cards are designed to accept a certain type of transmission
medium or network cable, which in turn determines the amount of information and
the speed at which that information can be sent. The NIC also contains a
transceiver, which converts the computer output signal into a signal that can be
transmitted over cable. In some instances a network interface card may also
contain 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 be
used by a client workstation solely to connect that computer to a network, while
others are used by network servers that are specifically designed to transfer
large amounts of information. A hub is a device used to concentrate and organize
network wiring. There are two basic types of hubs, active and passive. A passive
hub is simply a device that allows wiring connections in an orderly way. It
requires no power, and does no processing or regeneration of the traffic coming
through it. Another type of hub is an active hub, which contains circuitry that
can filter, amplify and control the traffic going through it. Hubs may also
contain additional utilities, such as bridging, manageabili
Active hubs are based on an extension of the network repeater. It does this by
accepting network traffic on its input side, and then amplifying the signal on
its 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 ports
that are typically wired to end-user workstation connections, although servers
and other devices can be attached as well. Signals on any port are transmitted
to all the other ports. Although a basic hub provides a way to organize cable
wiring, it does not segment or organize network traffic in any way. Hubs are
used in the design and implementation of a coherent and easily managed network
cabling system. In a typical design, a company may run cabling from a wall plate
in 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 wiring
hub. The hubs on each floor are then connected to the network backbone, which
runs from floor to floor in each wiring closet. This divides the network into
logical and physical groupings that simplifies troubleshooting and network
growth. Because of the signal boosting performed by the hub, it can also extend
the physical scope of the network. A recent innovation is the concept of the
switching hub. A switching hub basically bridges the output as well as the input
ports on the hub. With this arrangement, traffic from a port will not pass to
the hub unless it needs to access a different port than it came in on. If it
needs to pass across the hub to reach its destination, it only passes between
the two ports it needs, and is isolated from the rest of the ports. This cuts
down unnecessary traffic on all network segments attached to the hub, improving
the capacity and speed of the network. A bridge is used to interconnect two or
more similar LANs or to divide a large network into smaller more manageable
ones. Splitting of a large network with a bridge increases the efficiency of the
network and reduces the chances of an overload. A bridge is able to increase
effectiveness of two connected networks because it only passes information is
bound for the "far side" of the bridge if necessary. There are two
types of bridges, simple and learning. A simple bridge receives packets of
information and retransmits them to all ports until that packet reaches the
correct one. A learning bridge reads, stores, and learns the addresses of each
computer on the network. The learning bridge then constructs a table to
efficiently route packets to the correct port, without wasting resources sending
each packet to every port. If a packet comes through the bridge intended for a
destination not recorded on the bridging table, the bridge sends the packet out
to all ports and records the accepting destination. A repeater is a device that
extends the length of transmission media over which network information is
passed. A repeater accepts network input, amplifies the signal, and retransmits
the information. Repeaters are especially useful when a network is cabled
throughout a large building, over several floors. They are also able to filter
out interference or distortion before retransmission, but are unable to operate
efficiently when attempting to transfer huge amounts of information. A repeater
is a simple device contained in a stand alone box or within a hub
31b