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OverviewOverview

Introducing Computer Networks

Network Fundamentals

Local Area Networks (LANs) Wide Area Networks (WANs)

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Computer NetworkComputer Network

A collection of computers and related devices,

connected in a way that allows them to share

data, hardware, and software.

Network Interface Card (NIC) Network Operating System (NOS)

Workstation

Server

Hub

Router

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Why Use a Network?Why Use a Network?

Share hardware resources Hard drive space

CD-ROM drives

Modems Internet access

Printers

Copiers Share applications

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Why Use a Network?Why Use a Network?

Share data

Databases

Many programs designed to allow workgroup

collaboration

Connect people together

Email

Instant Messenger

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Network FundamentalsNetwork Fundamentals Two ways information is directed to its destination

Circuit switching Used in voice networks

Virtual complete circuit between two points

Packet switching Information broken down into pieces called packets

These packets are sent across the network

Routers guide these packets to their destination

Each packet could possible take a different route to thedestination

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Network FundamentalsNetwork Fundamentals

Protocols

A set of standards (rules) that dictate exactly

how two different components can

communicate

A group of protocols designed to work

together is called a protocol suite

The most popular Internet protocol suite is TCP/IP

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Network FundamentalsNetwork Fundamentals

Protocols

Network protocols are separated into layers

These layers of protocols are called a protocol

stack

Each layer has a specific function

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Local Area Network (LAN)

covers a relatively limited area such as a building.

Wide Area Network (WAN)

covers larger geographical areas

Personal Area Network (PAN)

Wearable computer communication

Bluetooth: http://www.bluetooth.com

Network ClassificationsNetwork Classifications

http://www.bluetooth.com/http://www.bluetooth.com/

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Network ClassificationsNetwork Classifications

Internet A collection of local, regional, and national

computer networks that are linked together to

exchange data and distribute processing tasks. Intranet

Private network limited to business or organization,that utilizes Internet technology (TCP/IP, HTTP).

Extranet An Intranet made accessible to certain outside

domains.

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Local Area Networks (LANs)Local Area Networks (LANs)

Connect computers within a room,

building, or a group of buildings

Very fast communication speeds (100

Mbps and higher)

Most popular LAN protocol is Ethernet

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Local Area Networks (LANs)Local Area Networks (LANs)

Required hardware

Network interface card (NIC)

Cable (if not wireless)

UTP (unshielded twisted pair)

Coaxial cable

Fiber optic cable

hub

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Local Area Networks (LANs)Local Area Networks (LANs)

Required software

Operating system that supports networking

All newer Microsoft Windows

Novell

Linux

Unix

Macintosh

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Local Area Networks (LANs)Local Area Networks (LANs) Topologies

Bus Star Ring

Media access control (MAC) How the LAN protocol governs access to the

network Ethernet uses a first come first serve method

Token Passing and CSMA/CD When two computers access at the same time

its called a collision

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Wide Area Networks (WANs)Wide Area Networks (WANs)

WANs allow a organization to connect its

computers in a private network throughout

the country or globe

The point of presence (POP) is a local

point of access to a WAN

The organization connects to the WAN

through a data line from the LEC

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Wide Area Networks (WANs)Wide Area Networks (WANs)

Backbone

Very high speed transmission lines

Public data network (PDN)

Companies that sell access to their WANcommunication network

WAN protocols

X.25

Switched multimegabit data service (SMDS)

Asynchronous transfer mode (ATM)

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CommunicationCommunication

Media and TechnologyMedia and Technology

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Communications NetworkCommunications Network

Combination of hardware,

software, and connecting

links that transport data.

http://www.privateline.com/manual/threeA.html

Analog Signal - Voice

A continuous, curvingsignal

Digital Signal - Data

A signal represented bybits

http://www.privateline.com/manual/threeA.htmlhttp://www.privateline.com/manual/threeA.html

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Bandwidth

The transmission capacity of a communications channel.

Measured in Bits Per Second (Kbps, Mbps)

Broadband: >256 Kbps (Ethernet / Cable Modem / DSL)

Narrowband: < 256 Kbps (Dial-Up)

Communications MediaCommunications Media

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2020

Communications MediaCommunications Media

Coaxial Cable (Broadband) Used for Cable TV, Faster than Twisted Pair

Consists of an inner conductor wire surrounded by a

conductive shield, which is surrounded by a non-

conductive jacket.

Fiber Optic Cable (Broadband) Many extremely thin strands of glass or plastic bound

together in a sheathing which transmits signals with lightbeams.

Fastest Available

Twisted Pair Wire Cable (Narrowband) Insulated pairs of wires historically used in telephone

service and to connect computer devices.

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Communications MediaCommunications Media

Microwave Communications

Line-of-sight devices which must be placed in

relatively high locations.

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Communications MediaCommunications Media

Satellite Transmission

Communications satellites are relay stations that

receive signals from one earth station and

rebroadcast them to another.

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Communications MediaCommunications Media

Wi-Fi

Uses Radio Frequency (RF)

Signals sent and received by

transceivers equipped with an

antenna used to provide

broadband wireless connectivity.

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Communications MediaCommunications Media

Infrared: Allows mobiledevices to communicate

wirelessly over short distances.

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Cellular Transmission

Signals from cells are transmitted to a receiver

and integrated into the regular network.

Communications MediaCommunications Media

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Home Networking TechnologyHome Networking Technology

Ethernet Wired Network

Home PNA Uses telephone lines in house as a network

special equipment needed to connect to telephonewall jack

Wireless Use radio frequencies

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