Transcript Getting To Know Networks

“Getting
to Know Networks”
What Is a Network?
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A network is a collection of computers hooked up together,
usually by cables or telephone wires, for the purpose of
sharing information and resources.
Commonly connected devices include personal computers
(PCs), ipods, ipads, cell phones, workstations, printers, fax
machines, pagers, and various data-storage devices.
Advantages of Networks
The most obvious benefit is that you can store virtually any
kind of information at a central location on the network as well
as access it from any connected computer. Other advantages
are:
1. Cost-effective Resource Sharing—peripherals can be
shared.
2. Streamlined Business Processes—tasks such as employee
collaboration on projects and holding meetings can take less
time and cost less.
3. Cheaper Sales Process—networks connect businesses to
customers through the electronic storefront: a Web site
allows customers to search for and order products and
services.
Advantages, Continued
4. Secure Management of Sensitive Information—the
ability to protect network resources and files. Proper
security features will control who will have access to
sensitive data, equipment, and other resources.
5. Worldwide, Instantaneous Access to Information—you
will be able to distribute critical information to many
locations anywhere in the world, almost instantaneously.
Recent Networked Peripherals
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Recently, other types of devices have become networkconnectable, including interactive televisions,
videophones, handheld devices (PDAs), cell phones, ipods,
and navigational systems like GPS (Global Positioning
Systems) and environmental control systems.
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Now networked devices everywhere will provide two-way
access to a vast array of resources on a global computer
network through the largest network of all—the Internet.
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Remember, a peripheral is any device connected to a
computer that performs a specific function (for example, a
printer).
Types of Network Stations
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LAN—Local area networks operate primarily over a small
area, such as an office building. The cables that hook parts
of the network up together are owned by the user.
WAN—Wide area networks covers a large area, such as all
the branches of a bank. It is usually connected through
leased telephone lines and satellite hookups.
Hardware Needed
1. Network Interface Cards—an expansion board inserted
into a computer so the computer can be connected to a
network.
2. Networking Software—directs the communication
functions, security protection, and data and peripheral
sharing within a group of computers. Examples include
Novell and Windows NT.
3. Networking Cabling—a bundle of wires with connectors
at both ends used to link parts of a computer system.
What about Cables?
A variety of cable types and sizes are available. Some of the
cables include:
 Coaxial Cabling—known as coax, it is the original
network cable, much like the cable used for cable TV. The
problem is that coax is expensive, stiff, has a wide diameter,
and is hard to run through walls.
 Twisted Pair Cabling—a commonly used cable made of
two insulated intertwined wires.
 Fiber Optics—hollow, strand-like cables that carry pulses
of light to transmit digital information.
What’s Network Physical Topology?
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“Network topology” refers to the layout of a network. Due
to the specific nature of computer network technology,
networks must be arranged in a particular way in order to
work properly. These arrangements are based on the
network hardware’s capabilities and the characteristics of
the various modes of data transfer. Some of them include:
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Ring
Bus
Star
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What Is a Ring Topology?
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Individual devices are connected
to a central hub, just as they are in
a star network. However, within
each hub the physical connections
form a ring.
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Each node is dependent on each
other, and information is sent in
one direction. Therefore, a
disruption at one node will cause
the nodes after to fail.
What Is a Bus Topology?
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A cable starts at what is called a
“head end,” and branches at
various points along the way.
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Information is sent in two
directions. However, if one node
becomes interrupted, the entire
system breaks down.
This topology is susceptible to
bottlenecking and single-point
failure.
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What Is Star Topology?
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The simplest form of the physical
star topology consists of multiple
cables—one for each network
device—attached to a single, central
connection device called a hub. All
information must go to the hub first.
The actual layout of the
transmission media need not form a
recognizable star pattern.
LAN Office Layout
Star Topology
secure room
network server
printer
10Base-T hub
scanner
twisted-pair cable
network
administrator
USB cable
workstation
digital camera
The Future of Wireless Technology?
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Wireless topologies differ greatly from wired topologies,
because the medium (radio frequencies) has different
properties than wires. The principles used in creating
wireless networking solutions are based on the technology
currently in use with cellular telephone systems.
So far, there have been four generations of mobile
technologies. The first generation is the analog cellular
system, the second is digital wireless, and the third
generation (3G), is often called UMTS (Universal Mobile
Telecommunications System). This system is designed to
be an always-on service for everything from voice to video
to data transfer. Fourth generation has just been released in
the iphones and other cell phones.
Thank you for viewing
“Getting to Know Networks”!