Intro to Info Tech

greydullNetworking and Communications

Oct 30, 2013 (3 years and 9 months ago)

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1

Intro to Info Tech

Networks





Copyright 2003 by Janson Industries

This presentation can be viewed on line at:

http://web.fscj.edu/janson/cgs1060/wk10.Networks.ppt

Copyright 2012 by Janson Industries

2

Objectives


Explain




Components of a network




Type of networks




Network providers






Copyright 2012 by Janson Industries

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Networks


Enable communication




Don't have to be computer
networks


Phone


TV


Radio


Cable


Copyright 2012 by Janson Industries

4

Networks


All have



Some device(s) /node(s) that
humans interact with that


Either receives and/or sends



Some device(s) to manage/direct
the communication



Some transmission medium



Copyright 2012 by Janson Industries

5

Computer Networks


Communication does not have to
be between people


EDI (electronic data interchange)


Download files




When it does, a "computer" acts
as the human interface device



GPS device


PDA (Palm, Blackberry)


Smart Phone


Copyright 2012 by Janson Industries

6

Network Classifications


Amount of area covered




Architecture




Topology




Wireless vs. physical lines




Copyright 2012 by Janson Industries

7

Networks


LAN


Local Area Network


Limited area


A room, a home, a building, a small
group of bldgs


Shared resources


printer



MAN


Metropolitan Area Network


High speed network that connects
LANS


Usually larger area


Town, city, county


Ex. Comcast's cable based network

Copyright 2012 by Janson Industries

8

Networks


WAN


Wide Area Network



Largest geographic area


State, country, world



Can be a bunch of LANS/MANS tied
together


The Internet



Or can be a single high speed network


Satellite phone network

Copyright 2012 by Janson Industries

9

Network Architectures


Client/Server



Server acts as network's storage



Manages the network resources


Web pages, data, pictures, music



Can have many different types


Print Server


Application Server


File Server

Copyright 2012 by Janson Industries

10

Network Architectures


Peer to Peer


Each computer acts as a server


Has unique resources


files, printer


Provides access for all other network
computer s



P2P (Internet Peer to Peer)


Uses the Internet to share resources


S/W enables users to access other
currently logged on users computers


BitTorrent, Kazaa, LimeWire

Copyright 2012 by Janson Industries

11

Network Topologies


"Shape" of the network


Bus


Single line, bidirectional


Node fails


no prob


Ring


Single line, unidirectional


Each device involved in routing


Node fails, all nodes after unavailable


Star


Central routing hub/switch


Node fails


no prob


Hub fails


network fails


Copyright 2012 by Janson Industries

12

Network Media


Physical Lines



Twisted Pair


Two twisted copper wires


Can have many in one cable


Phone land lines


Not good for long distances



Coaxial Cable


Single shielded copper wire


No noise


Good for longer distances


Cable company


Copyright 2012 by Janson Industries

13

Network Media


Physical Lines



Fiber Optic



Many shielded glass/plastic lines



Transmit light



Vs. copper wires


No interference from other electrical devices


Smaller, lighter and faster


More expensive and harder to install and
modify

Copyright 2012 by Janson Industries

14

Network Media


Wireless



Infrared



Often used by peripherals (wireless
mouse, keyboard, printer)



Need line of sight



Broadcast Radio



Good for broad area transmissions



Wi
-
Fi, Bluetooth


Copyright 2012 by Janson Industries

15

Network Media


Wireless



Cellular Radio



High frequency radio waves



Uses network of towers to relay signal



Popular with mobile devices



Microwave



Ultrahigh frequency radio waves




Called fixed wireless because
transmitted from dish to dish



Line of sight needed


On top of buildings: Empire State Bldg


Copyright 2012 by Janson Industries

16

Network Media


Wireless



Satellite



Receives transmissions from earth
based station



Relays to other earth based station


Often microwave



Vs. terrestrial wireless


Wide range


half the Earth


Less interference


Less real estate needed
-

no towers, relay
stations, wires, etc.


Satellites are expensive


Difficult to repair



How many satellites are there?

Copyright 2012 by Janson Industries

17

Network Providers


Do it yourself


Lay your copper wire


Get a router


Hotels, schools, businesses



Common Carriers


Regulated by gov't


Must provide access to anyone


Phone company, cable company



Value Added Network


Provide a service over common
carrier line (1
-
800
-
Big
-
Date)


Copyright 2012 by Janson Industries

18

Phone Company Services


Switched vs. Dedicated Lines


Switched uses standard telephone
lines


Dedicated connects two points


Provides constant connection


Advs and Disadvs?



Dial up connection


Use the telephones switched network


Temporary analog connection


Problem: computers are digital


Need a modem


Copyright 2012 by Janson Industries

19

Phone Company Services


ISDN (Integrated Services Digital
Network)


Digital over copper (faster than dial up)


Need ISDN modem


Distance limitation


3.5 miles




DSL (Digital Subscriber Line)


Digital over copper (faster than ISDN)


Need DSL modem and network card


Distance limitation


3.5 miles


Copyright 2012 by Janson Industries

20

Phone Company Services


FTTH/FTTB

Fiber to the
Home/Business


The last quarter mile problem


Very fast


Distance limitation


3.5 miles




T Lines (T1, T2, T3)


High speed lines


Usually make up the backbone of a
network


Copyright 2012 by Janson Industries


With cable need cable modem



Wireless modem



Router


Manages transmissions over the
network


Home routers enable multiple
computers to share Internet
connection

21

Network Equipment

Copyright 2012 by Janson Industries

22

Network Standards


Protocols dictate how two devices
communicate over the network




Network standards dictate h/w


Connectors


Medium


Cabling


Plug types


Speed



Copyright 2012 by Janson Industries

23

Network Standards


Ethernet is most popular for LANS


Easy to install and cheap


No central controlling device


Two computers trying to send at same
time cause a "collision"



Token Ring


Token passes around network


Only one token so only one computer
can communicate at a time


No collisions



Copyright 2012 by Janson Industries

24

Wireless Network Standards


WiFi (Wireless Fidelity) similar to
Ethernet for radio wave communication




UWB (Ultra Wideband)


Short range, high speed, radio wave
communication


Video and image transfers




IrDA: infrared communications


Must be line of sight


Copyright 2012 by Janson Industries

25

Wireless Network Standards



RFID: radio communication between a
reader and a tag


Tag consists of an antenna and
memory



Sprint’s WiMAX (Worldwide
Interoperability for Microwave Access)
MW communication over a WAN


Dictates how devices talk to towers,
towers communicate to Internet or
other towers


Like WiFi with a bigger hotspot

Copyright 2012 by Janson Industries

26

Wireless Network Standards



Verizon’s LTE (Long Term
Evolution)


Same as Sprint’s WiMAX: MW
communication over a WAN


Dictates how devices talk to towers,
towers communicate to Internet or
other towers

Copyright 2012 by Janson Industries

27

Protocols


TCP/IP dictate how Internet
communications work



Bluetooth how short range radio
communication work


Include non
-
computer devices like


Headsets, fax machines, cameras



WAP (Wireless Application Protocol)


How smaller devices display Internet
resources


Web page on a phone


Email to blackberry


Copyright 2012 by Janson Industries

28

Points to Remember


Communication networks require
both h/w and software



Standards dictate h/w, protocols
dictate s/w



Computer networks have at least:


User node


Medium


Communication management device