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the term network describes two or more connected

computers that can share a resource such as data, a

printer, an Internet connection, applications, or a

combination of these. Today, two types of networks are

in common use: Local area network (LAN) Wide area

network (WAN)

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Local area network (LAN)

Wide area network (WAN)

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a LAN is limited to a specific area, usually an office, and cannot

extend beyond the boundaries of a single building.

it’ s still best to split a big LAN into smaller logical zones known asworkgroups to make administration easier.

A workgroup is a set of devices with no security association with oneanother

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a WAN as any network that uses routers and public network links like The Internet

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• Workstations. • Servers. • Hosts.

Copyright 2007 Kenneth M. Chipps

PhD www.chipps.com 6

Workstations are often seriously powerful computers that run more than one central processing unit (CPU)

Servers are also powerful computers. They get their name because they truly are “at the service” of the network and run specialized software known as the network operating system to maintain and control the network.

Host means any network device with an IP address.

Copyright 2007 Kenneth M. Chipps

PhD www.chipps.com 7

Packet Tracer is a program used to illustrate how computer networks work

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Packet Tracer has two different views◦ Logical Workspace

◦ Physical Workspace

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Let’s create a sample network to see how Packet Tracer simulates a network

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To add a PC onto the workspace:

Select End Devices

Drag [Generic] onto workspace

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Under End Devices, these are the following devices available:

Double-click [PC1]

Change name to “ITE CW”

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Drag second PC

Double-click [PC2]

Change name to “ITE CC”

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Under Connections, select the Copper Straight-through cable, the solid black line, and make a connection between the devices with it

The red lights on the link indicate that the connection is not working

The point is the simulator will do what you tell it, whether that is right ort wrong

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Under Connections, select the Copper Cross over cable

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Click PC1, choose [Fast Ethernet0]

Move to PC2, click, choose [FastEthernet0]

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To delete any item, select and

click Delete Button

Click [Place Note tool]

Add a title “A network of 2 PCs]

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Logical topologies describe how signals act on the network.

a physical topology defines how nodes in a network are physically linked

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the purpose of networking is to share resources.How this is accomplished depends on thearchitecture of the network operating systemsoftware. The two most common network typesare

peer-to-peer

and client/server.

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Peer-to-Peer Network

In peer-to-peer networks, the connected computers have no centralized authority. If a user of one computer wants access to a resource on another computer, the security check for access rights is the responsibility of the computer holding the resource.

Each computer in a peer-to-peer network can be both a client that requests resources and a server that provides resources.

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Client/Server Network

In contrast to a peer-to-peer network, a client/server network uses a network operating system designed to manage the entire network from a centralized point, which is the server. Clients make requests of the server, and the server responds with the information or access to a resource.

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Bus Star Ring Mesh Point to point Point to multipoint Hybrid

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In a bus topology, all computers are attached to a single continuous cable that is terminated at both ends, which is the simplest way to create a physical network.

Copyright 2007 Kenneth M. Chipps

PhD www.chipps.com 26

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Unlike in a bus topology, each computer in a star topology is connected to a central point by a separate cable. The central point is a device known as a hub.

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In the ring topology, each computer is connected

directly to two other computers in the network. Data

moves down a one-way path from one computer

to another

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In a mesh topology, a path exists from each station

to every other station in the network

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Network communication in which two devices have exclusive access to a network medium. For example, a printer connected to only one workstation would be using a point-to-point connection.

Copyright 2007 Kenneth M. Chipps

PhD www.chipps.com 34

consists of a central base station that supports several subscriber stations. These offer network access from a single location to multiple locations, permitting them to use the same network resources between them

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utilizes a mix of two or more topologies a nignitluser eht taht yawnetwork ton seoddradnats eht fo eno tibihxetopologies

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All the network segments and servers connect to and what gives the network its structure. Network optimization performance its speed and efficiency it follows that you would want to connect all of the network’ s servers and segments directly to the network’ s backbone.

Any small section of the network that may be connected to, but isn’t actually a piece of, the backbone. The network’ s workstations and servers organized into segments connect to the network backbone, which is the common connecting point for all segments.

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Backbone and segments on a sample

network