network basics
TRANSCRIPT
NETWORK BASICS
•NETWORK*** - A COMMUNICATIONS SYSTEM CREATED BY
LINKING TWO OR MORE DEVICES AND ESTABLISHING A
STANDARD METHODOLOGY IN WHICH THEY CAN
COMMUNICATE
HISTORY OF EXCHANGING DATA
•AT FIRST ‘MAINFRAME’ COMPUTERS
•EXCHANGED DATA VIA A ‘DUMB’ TERMINAL CONNECTED
DIRECTLY WITH THE MAINFRAME
•PERSONAL COMPUTERS / APPLES
•EXCHANGED DATA VIA FLOPPY DISKETTES
•PRIORITY NETWORKS ESTABLISHED (NOVELL)
UNIT OF MEASUREMENT FOR TELECOMMUNICATION DEVICES
•BANDWIDTH
•MEASURED IN BITS PER SECOND* (BPS)
•BROADBAND – (CABLE, DSL)
•NARROWBAND – (PHONE)
CLIENT/SERVER NETWORKS
• CLIENT* - A COMPUTER THAT IS DESIGNED
TO REQUEST INFORMATION FROM A
SERVER (YOUR MACHINE)
• SERVER* - A COMPUTER THAT IS
DEDICATED TO PROVIDING
INFORMATION IN RESPONSE TO
EXTERNAL REQUESTS
MEDIA
• NETWORK TRANSMISSION MEDIA - REFERS TO THE VARIOUS TYPES
OF MEDIA USED TO CARRY THE SIGNAL BETWEEN COMPUTERS
•WIRE MEDIA (GUIDED - PHYSICAL)
•WIRELESS MEDIA
(UNGUIDED)
WIRE MEDIA – “GUIDED”
• WIRED MEDIA - TRANSMISSION MATERIAL
MANUFACTURED SO THAT SIGNALS WILL BE
TRANSFERRED OVER A PHYSICAL MEDIUM
TELEPHONE LINES
•ADVANTAGES-
• INEXPENSIVE
•WIDELY AVAILABLE
• EASY TO CONNECT
•DISADVANTAGES
• SLOWER SPEEDS (56 KBPS)
•DISTANCE LIMITATIONS
• SECURITY
•WEATHER
Called “Twisted Pair”
COAXIAL CABLE
•ADVANTAGES-
•WIDELY AVAILABLE
• EASY TO INSTALL
• FASTER THAN PHONE
•DISADVANTAGES
• SECURITY
• SHARED NETWORK –
MORE USERS SLOWER
SPEEDS
Cable into your house200 Mbps to 1 Gbps (download)Uploads are slower
FIBER OPTIC CABLE
•ADVANTAGES-
• SPEED (UP TO 10 GB)
• SECURITY
•MULTIPLE TRANSMISSIONS
•NOT EFFECTED BY WEATHER
•DISADVANTAGES
• EXPENSIVE
•DIFFICULT TO INSTALL
WIRELESS - UNGUIDED MEDIAMICROWAVE
•ADVANTAGES-
•DO NOT NEED
PHYSICAL WIRE
•UP TO 56 MBPS
•DISADVANTAGES
•SECURITY
•LINE OF SITE RESTRICTIONS
•WEATHER
SATELLITES
• ADVANTAGES-
• TRANSMIT AROUND THE WORLD
• ONE UPLOAD OF DATA, MANY DOWNLOADS
• DISADVANTAGES
• EXPENSIVE
• TIME LAG (DISTANCE)
• SECURITY
BLUETOOTH• EMBEDS TINY RADIO TRANSMITTERS IN DEVICES
• USES UNLICENSED RADIO BANDWIDTH
• CHANGES FREQUENCY CONSTANTLY TO PREVENT INTERCEPTION
• DISADVANTAGES
• 5 TO 10 METER DISTANCE
• ADVANTAGES-
• WORLDWIDE USAGE DUE TO
UNLICENSED RADIO BANDWIDTH
• MANY DEVICES TO TALK TO EACH
OTHER
INFRARED• USES LIGHT WAVE TO TRANSMIT DATA
• DISADVANTAGES
• LINE OF SITE
• WALLS STOP IT
• ADVANTAGES-
• INSTALLATION IS EASY
• CUBICLES IN OFFICES CAN EASILY BE
RECONFIGURED
• WALLS STOP IT
RADIO FREQUENCY IDENTIFICATION (RFID)
•RADIO FREQUENCY IDENTIFICATION (RFID) - USES ELECTRONIC
TAGS AND LABELS TO IDENTIFY OBJECTS WIRELESSLY OVER
SHORT DISTANCES
CHALLENGES OF BUSINESS MOBILITY
•PROTECTING AGAINST THEFT
•PROTECTING WIRELESS CONNECTIONS
•PREVENTING VIRUSES ON A MOBILE DEVICE
•ADDRESSING PRIVACY CONCERNS WITH RFID
INTERNET - HISTORY
• FORMED BY THE US GOVERNMENT AND UNIVERSITIES IN THE 1969 TO EXCHANGE
DATA
• WANTED TO AVOID THE “COLD WAR” SNOOPING.
EXPANSION OF THE INTERNET
•THE FEDERAL GOVERNMENT DECIDED TO NO LONGER PAY FOR
THE SWITCHING EQUIPMENT IN THE EARLY 1990’S.
•SPRINT, AT&T, MCI JUMPED IN AND FORMED THE BACKBONE OF
THE INTERNET TRAFFIC (FOR A FEE FROM YOUR INTERNET
PROVIDER)
HOW DOES IT WORK?
IP ADDRESSES
(INTERNET PROTOCOL)
TRANSLATES WWW.UNCW.EDU TO AN IP ADDRESS LIKE 152.20.201.15
IP (INTERNET PROTOCOL) ADDRESSES
• ALL ‘NODES’ ON THE INTERNET HAVE A UNIQUE IP ADDRESS (SIMILAR TO A PHONE NUMBER)
• AN IP ADDRESS IS UP TO 12 DIGITS IN 3 DIGIT PAIRS AS IN: XXX.XXX.XXX.XXX
• UNCW’S ‘AREA’ CODE: IS 152.20
• ENTROPY’S IP ADDRESS IS: 152.20.244.225
• THIS MACHINE IS: HTTP://WHATISMYIPADDRESS.COM/