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WHAT IS THE INTERNET?

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

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WHAT IS THE INTERNET?

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  1. WHAT IS THE INTERNET? IT IS NOT OWNED BY ANYONE IT IS NOT HOMOGENEOUS NO CENTRALIZED MANAGEMENT OVERSIGHT ORGANIZATIONS

  2. 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

  3. WHAT IS THE INTERNET? IT IS: • COMPLEX • WORLDWIDE • PUBLICLY ACCESSIBLE • PACKET SWITCHING XMISSION TECHNOLOGY • HAS INTERCONNECTED NETWORKS • DOMESTIC • ACADEMIC • BUSINESS • GOVERNMENT • COMMERCIAL

  4. INTERNET HISTORY • 1957 SPUTNIK • 1958 DOD-ARPA, ADVANCED RESEARCH PROJECT AGENCY FORMED • 1965 1st 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 1ST NETWORK E-MAIL TRANSMITTED BETWEEN COMPUTERS • 1973 FTP PROTOCOL INTRODUCED/IMPLEMENTED BY ARPANet • 1973 ROBT. KAHN & VINTON CERF BEGAN WORK ON TCP/IP • 1975 1ST COMMUNICATION TEST USING TCP/IP • 1975 ARPA TURNED ARPANet OVER TO DCA • 1978 PACKET SWITCHED NETWORKS EXPANDED TO EUROPE

  5. 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

  6. 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

  7. TCP/IP STACK LAYER

  8. INTERNET DOMAIN NAMEDOMAIN NAME racorinda@pacbell.net http://www.yahoo.com http://finance.yahoo.com.us/marketupdates/overview.html • 1st LABEL TO LEFT OF “/” IS THE TOP DOMAIN, GEOGRAPHICALLY us=U.S., ca=Canada, fr=France, de=Germany, ru=Russia, es=Spain, jp=Japan • 2nd LABEL TO LEFT IS THE TOP DOMAIN, GENERIC .biz, .com, .edu, .info, .net, .org, .info, .mil, .arpa, .museum • 3rd LABEL TO LEFT IS SECOND LEVEL DOMAIN • REMAINING LABELS TO LEFT ARE SUB-DOMAINS UNDER CONTROL OF THE SECOND LEVEL DOMAIN

  9. INTERNET DOMAIN NAMEIP ADDRESS

  10. DOMAIN NAME REQUEST ROOT SERVER IP Request: yahoo.com NAME SERVER FOR LOCAL ISP 2 22 3 Address For: yahoo.com 4 IP Request: Finance NAME SERVER FOR yahoo.com 1 5 IP Request: finance.yahoo.com/ Address For: Finance FINANCE SERVER AT YAHOO.COM 6 Communications Established 7 http://finance.yahoo.com/marketupdates/overview.html

  11. YAHOO.COM GATEWAY SERVER FIREWALL BRIDGE/SERVER FINANCE.YAHOO.COM SERVER YAHOO.COM NAME SERVER

  12. DATA PACKET • E-MAIL CLIENTWEB 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

  13. PORTS – VIRTUAL ENTRANCEWAY BETWEEN YOUR COMPUTER & THE INTERNET TOTAL AVAILABLE PORTS = 65,535

  14. 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/

  15. 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.

  16. EMAIL TRANSMISSION DIAGRAM smtp.att.yahoo.com CLIENT HEADER PORT SMTP: 115/465 HTTP: 80 AOL: 531 Attach: BODY PORT POP3: 110/995 IMAP4:220/993

  17. WORLD WIDE WEB (www) or“The Web” SIR TIMOTHY BERNERS-LEE CREATED WEB TECHNOLOGY MARC ANDREESSEN CREATED THE FIRST BROWSER

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