ppt - Computers

orangesvetElectronics - Devices

Nov 8, 2013 (3 years and 7 months ago)

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WHAT IS THE INTERNET?


IT IS NOT OWNED BY ANYONE


IT IS NOT HOMOGENEOUS


NO CENTRALIZED MANAGEMENT


OVERSIGHT ORGANIZATIONS




WHAT IS THE INTERNET?


PROVIDES COMMUNICATIONS SERVICES


E
-
MAIL


FILE TRANSFER


ONLINE CHAT


AUDIO & VIDEO


WORLD WIDE WEB


INTERLINKED WEB PAGES


SEARCH


INSTANT MESSAGING


E
-
SHOPPING

WHAT IS THE INTERNET?

IT IS:


COMPLEX


WORLDWIDE


PUBLICLY ACCESSIBLE


PACKET SWITCHING XMISSION TECHNOLOGY


HAS INTERCONNECTED NETWORKS


DOMESTIC


ACADEMIC


BUSINESS


GOVERNMENT


COMMERCIAL


INTERNET HISTORY



1957


SPUTNIK


1958


DOD
-
ARPA, ADVANCED RESEARCH PROJECT AGENCY FORMED


1965


1
st

EMAIL, TIMESHARE TO MAINFRAME COMPUTER


OCT. 1968

ARPANet WORKING GROUP MET AT SRI


NOV. 1969

ARPANET UCLA
-
SRI COMPUTER LINK ESTABLISHED


DEC. 1969

UCLA
-
SRI
-
UCSB
-
UofUTAH LINK
-
UP


1971


1
ST

NETWORK E
-
MAIL TRANSMITTED BETWEEN COMPUTERS


1973


FTP PROTOCOL INTRODUCED/IMPLEMENTED BY ARPANet


1973


ROBT. KAHN & VINTON CERF BEGAN WORK ON TCP/IP


1975


1
ST

COMMUNICATION TEST USING TCP/IP


1975


ARPA TURNED ARPANet OVER TO DCA


1978


PACKET SWITCHED NETWORKS EXPANDED TO EUROPE





INTERNET HISTORY


CONTD.



1979


CompuServ

OFFERS E
-
MAIL SERVICE


1981


NETWORKS EXPANDED TO CANADA, HONG KONG, & AUSTRALIA


1982


TCP/IP ADOPTED FOR ALL MILITARY COMPUTER NETWORKS


1983


-

TCP/IP REPLACES PRIOR PROTOCOL USED BY
ARPANet



-

MILITARY PORTION OF
ARPANet

SPUN OFF TO
MILNET



-

DOMAIN NAME SYSTEM INVENTED


1986


NATIONAL SCIENCE
FND

NETWORK(
NSFNetwork
) ON LINE



REPLACING
ARPANet


1988


-

NSFNet

PRINCIPAL INTERNET BACKBONE WORLDWIDE



-

NSFNet

CREATED 5 SUPER CONDUCTOR CENTERS



-

NSFNet

WAS THE PRINCIPAL INTERNET BACKBONE


1991


TIM BERNERS
-
LEE RELEASES WORLD
-
WIDE WEB (WWW)



1993


MOSAIC (PRECURSOR TO NETSCAPE) MADE AVAILABLE TO PUBLIC


1994


NSFNet

TRAFFIC PASSES 10 TRILLION BYTES/MONTH


1995


NSFNet

DECOMMISSIONED; INTERNET TURNED OVER TO ISPs &


TRANSMISSION CARRIERS



PROTOCOLS


RULES OR CONVENTIONS


TCP (TRANSMISSION CONTROL PROTOCOL)


CONTROLS

PACKAGING OF DATA INTO PACKETS AT SOURCE AND

RECOMBINES DATA AT DESTINATION


IP (INTERNET PROTOCOAL)


CONTROLS THE ROUTING

OF DATA OVER THE INTERNET


UDP (USER DATAGRAM PROTOCOL)


ALSO CONTROLS

PACKAGING OF DATA INTO PACKETS SIMILAR TO, BUT

NOT AS RELIABLY TRANSMITTED, AS TCP. USED FOR

STREAMING AUDIO/VIDEO

TCP/IP STACK LAYER



INTERNET DOMAIN NAME

DOMAIN NAME


racorinda@
pacbell.net

http://www.
yahoo.com

http://
finance.yahoo.com.us/marketupdates/overview.html



1
st

LABEL TO LEFT OF “/” IS THE TOP DOMAIN, GEOGRAPHICALLY

us=U.S., ca=Canada, fr=France, de=Germany, ru=Russia, es=Spain, jp=Japan


2
nd

LABEL TO LEFT IS THE TOP DOMAIN, GENERIC

.biz, .com, .edu, .info, .net, .org, .info, .mil, .arpa, .museum


3
rd

LABEL TO LEFT IS SECOND LEVEL DOMAIN


REMAINING LABELS TO LEFT ARE SUB
-
DOMAINS UNDER CONTROL OF
THE SECOND LEVEL DOMAIN



INTERNET DOMAIN NAME

IP ADDRESS





DOMAIN NAME REQUEST

IP Request:

finance.yahoo.com/

NAME SERVER
FOR LOCAL ISP

IP Request:

yahoo.com

Address For:

yahoo.com

IP Request:

Finance

Address For:

Finance

Communications
Established

ROOT SERVER

NAME SERVER FOR
yahoo.com

1

2
2

2

3

7

4

5

6

http://finance.yahoo.com/marketupdates/
overview.html

FINANCE SERVER AT
YAHOO.COM

YAHOO.COM

GATEWAY SERVER

YAHOO.COM

NAME SERVER

FINANCE.YAHOO.COM

SERVER

FIREWALL

BRIDGE/
SERVER






E
-
MAIL CLIENT


WEB BROWSER



DATA



HEADER

<1500 BYTES








IP VERSION


HEADER LENGTH


PACKET PRIORITY, QUALITY OF SERVICE


PACKET LENGTH, BYTES


TAG TO HELP RECONSTRUCT PACKET


TAGS TO PERMIT FRAGMENTATION/MORE TO


FOLLOW?


FRAGMENT ORDER TAG


TIME TO LIVE BEFORE PACKET TO BE


DISCARDED


TRANSPORTATION PROTOCOL (E.G., TCP,
UDP
)


HEADER CHECKSUM


SENDER IP ADDRESS


DESTINATION ADDRESS


OPTIONAL TAGS


DATA PACKET

PORTS


VIRTUAL ENTRANCEWAY BETWEEN
YOUR COMPUTER & THE INTERNET

TOTAL AVAILABLE PORTS = 65,535

PORT NO.

DESCRIPTION

20/TCP

FTP

data

21/TCP

FTP

control (command)

23/TCP,UDP

Telnet protocol

unencrypted text communications

25/TCP,UDP

Simple Mail Transfer Protocol (SMTP)

used for e
-
mail routing between mail servers

53/TCP,UDP

Domain Name System (DNS)

70/TCP

Gopher protocol

80/TCP

Hypertext Transfer Protocol (HTTP)

109/TCP

Post Office Protocol 2 (POP2)

110/TCP

Post Office Protocol 3 (POP3)

115/TCP

Simple File Transfer Protocol (SFTP)

220/TCP,UDP

IMAP
, Interactive Mail Access Protocol, version 3

465/TCP

SMTP over
SSL

513/TCP

Login

531/TCP,UDP

AOL Instant Messenger, IRC

532/TCP

netnews

OUTGOING E
-
MAIL:

SMTP


Port 115

POP3 Port 110



SMTP W/SSL Port 465

POP 3 W/SSL Port 995

IF YOU USE A NON
-
STANDARD PORT YOU MUST SPECIFY THE PORT NUMBER BEING USED IN THE
URL; E.G., http://www.parishilton.com:81/

E
-
MAIL


METHOD OF WRITING, SENDING, RECEIVING AND SAVING MESSAGES USING AN
ELECTRONIC COMMUNICATION SYSTEM




COMMON PROTOCOLS


-

POP (POST OFFICE PROTOCOL): DELETES MSGS ON SERVER WHEN D/L


-

IMAP

(INTERNET MESSAGE ACCESS PROTOCOL): LEAVES MSGS ON SERVER


-

WEBMAIL (HTTP PROTOCOL): ACCESS MAIL SERVER WITH BROWSER


-

SMTP (SIMPLE MAIL TRANSFER PROTOCOL): STANDARD FOR OUTGOING MAIL


-

PROPRIETARY PROTOCOLS: FOR INTRANET SYSTEMS, LIKE AOL/COMPANIES


-

HTML (HYPERTEXT MARKUP LANGUAGE): MESSAGE BODY


-

MIME (MULTIPURPOSE INTERNET MAIL EXTENSIONS): PERMITS TEXT OTHER


THAN ASCII, TEXT & NON
-
TEXT ATTACHMENTS, AND MULTIPLE PART MSGS.

Attach:

HEADER

BODY

CLIENT

PORT

SMTP: 115/465

HTTP: 80

AOL: 531

PORT

POP3: 110/995

IMAP4:220/993

EMAIL TRANSMISSION DIAGRAM

smtp.att.yahoo.com

WORLD WIDE WEB (www) or

“The Web”


SIR TIMOTHY BERNERS
-
LEE CREATED

WEB TECHNOLOGY


MARC ANDREESSEN CREATED THE FIRST

BROWSER