Internet / Intranet CIS-536

1. Internet / IntranetCIS-536 Class 9

2. Class 9 Agenda • Miscellaneous Topics • Cybersquatting • Plug-Ins, Multimedia • Development Environments

3. Cybersquatting • Cybersquatting • Registering a Domain Name • Contains or Resembles Well-Know Commercial Names or Names of Individuals • With Intent to: • Prevent Others From Using the Name • Profit by Selling Domain Name to Trademark Owner or Individual • Trademark Law • Legal Action Only if Domain Name is Used • Anticybersquatting Consumer Protection Act • November 29, 1999 • Civil Lawsuits May be Filed by Trademark Holder • Against anyone who Registers, Traffics In, or Uses • Domain Name Identical or Confusingly Similar to Protected Trademark • Bad Faith Intent to Profit • “Confusingly Similar” to be Decided By Courts

4. Cybersquatting (2) • Effects • Reduce the Number of Domain Names • Legitimate Holders May Face Litigation • Bad Faith Factors: • Harm Goodwill of Trademark Holder • Offer to Sell Domain Without Actually Using it in Bona Fide Offering of Goods and Services (or past pattern of such conduct) • Obtained Under False Pretenses • Acquisition of Multiple Domain Names With Knowledge That They are Similar to Protected Marks

5. Cybersquatting (2) • Effects • Reduce the Number of Domain Names • Legitimate Holders May Face Litigation • Bad Faith Factors: • Harm Goodwill of Trademark Holder • Offer to Sell Domain Without Actually Using it in Bona Fide Offering of Goods and Services (or past pattern of such conduct) • Obtained Under False Pretenses • Acquisition of Multiple Domain Names With Knowledge That They are Similar to Protected Marks

6. Cybersquatting (3) • Absence of Bad Faith: • Domain Holder Has Legal Rights to It • Domain Name Commonly Used by Its Holder • Past Use of Name in Conjunction with Bona Fide Goods or Services • Noncommercial or Fair-Use Purposes • Name Not Distinctive and Famous When Registered • Reasonable Grounds to Believe it was Lawful • Penalties • Domain Name Cancelled or Forfeited to Rightful Owner • Damages Up to $100,000 per Domain Name • Jurisdiction • Court Where Domain Name Registrar is Located • Network Solutions Located in Virginia • Domain Name Registrars are Protected

7. Cybersquatting(4) • ICANN Policies as a Result • Mandatory Arbitration • Most Registrars Expected to Adopt it • Some Ambiguities in the Law • Challenges Expected

8. A Quick Word About Java • JavaScript is Interpreted By the Browser • Run Within Browser Environment • Limited by Browser’s Capabilities • Source Code is Part of HTML Page • Java is a Completely Separate Language • Browser Transfers a Java Program (“Applet”) to the Local Machine and Runs It • Output of Java Can Be Displayed Within the Browser • Designed to Be Safe For Web Use • Otherwise Similar to Transfering .exe Programs • Compiled Into .class Files • Pseudo-code: Requires a Java Virtual Machine to Run • Source Code Hidden From Users • Does Not Have Access to Page Internals (DOM)

9. Including a Java Applet in Your Page • <APPLET CODEBASE=“./japplets” CODE=“myapplet.class” HEIGHT=100 WIDTH=200 > • <PARAM Name=Whirl Value=“True”> • <PARAM Name=Title Value=“WhirlyDemo”> • </APPLET>

10. Plug-Ins • Platform Specific Extensions to Web Browsers • Client Side Equivalent to Server Extensions • Associated With a File Extension • Similar to MS-Windows Associations • If Installed, Files With Extension Will Invoke Program on Browser • Including a Plug-In in HTML • <EMBED SRC=“filename.ext” WIDTH=200 HEIGHT=200 PINAMEx = VALUE PINAMEy = VALUE > • Height, Width Where Data is to Be Displayed in Browser Window • Name/Value Pairs are Arguments to the Plug-In • <NOMBED> </NOEMBED> Used to Provide Alternative • Plug-In Must Be From a Trusted Source • Like Any Other Program. Has Full Access to Local Computer • Plug-In Development • Netscape, Microsoft Provide SDK’s

11. Active X • Microsoft Specific • “Plug-In” Technology That Allows Components to Run in Browser • Components are Accessible By Other Programs via OLE • Allows Developers to Develop Internal Controls That are Web Enabled • Key Advantage is Distribution • Active X Components Can Be Distributed via the Web • Automatically Downloaded As Part of Web Page (Unlike Plug-Ins) • Default Security Asks for Confirmation • Must Come From a Trusted Source • Typically Used For Intranet Type Applications • Or Large Commercial (“Trusted”) Organization • E.g. Microsoft • Certificates Verify Creator of Control • Third Party Verifies Sender is Who They Say They Are • OLE Documents Allow Including a Document in Another Application • E.g. Microsoft Office Applications Can Run Within Browser • Embed Into Web Page Using <CONTROL> Tag • Many Arguments. Typically Use ActiveX Control Pad to Insert Info

12. Multimedia • Sound • <BGSOUND SRC=“URL” LOOP=“Infinite”> • Internet Explorer Only • Can Appear Anywhere in <BODY> • Best to Place it Near End • Otherwise Graphics Won’t Load Until Sound is Loaded • Default: Loop = 1 • Supports .wav, .au, .mid Formats • <EMBED src=“music.wav”> • Requires Sound Plug-In (e.g. Real Audio) • Video • <EMBED src=“movie.mpg”> • Requires Plug-In (or Download and Play Separately) • <IMG DYNSRC=“movie.mpg” START=“mouseover” WIDTH=“150” HEIGHT=“100” LOOP=“-1”> • START – indicates when video should play

13. Multimedia (2) • Environments • Shockwave / Flash • Development Environment Plus Plug-In Playback • Allows Development of Animations • User Interactivity • Audio Formats • .mid – Provides the Music “Score” • Algorithm Generates the Music • .wav – Microsoft Windows Sound File • .au, .aif – Sun, Apple Sound Files • .mp3 – Near CD-Quality Format. Great Compression. • Video Formats • .avi – Microsoft Windows Video File • .qt, .mov – Apple QuickTime Movie Format • .mpg, .mpeg – Current Internet Video Standard • .rm – Real Media. Proprietary Video Format

14. Streaming Multimedia • Problem: Audio/Video Take a Long Time To Download • Technologies Require File to Be Downloaded Before Playing • Client Pull: Poor Solution • Requires Breaking Up the A/V into Small Files • Choppy Results • Solution: Stream the Transmission : Play in Near Real Time • Play the A/V as It’s Being Sent • Requires a Session to Be Efficient • HTTP is Stateless (No Sessions) • Plug-Ins Don’t Have to Use HTTP • Can Use TCP/IP Directly

15. Streaming (2) • Streaming Issues • Broadcast vs. PlayBack • Coordination of Video/Sound is Non Trivial • Require Significant Compression (Scalable) • Lower Resolution as Bandwidth Degrades • Many Compression Algorithms Don’t Work in Real Time • Must Deal With Differing Bandwidths • Server Performance • Internet Issues • Packet Based • Can’t Rely on Consistent Bandwidth • Packets May Arrive in Different Order • Errors Require Retransmission • “Human Processing” • Video Can Become Choppy With Minor Inconvenience • Lost Packets Can Be Skipped • Choppy Audio is Unintelligible • Lost Packets Can Not Be Skipped

16. Streaming Tricks • Continued Improvements Expected • Compression (Hardware and Software) • Buffering • Buffered Transmission Can Cover Glitches • Technology • UDP • Faster Than TCP • Doesn’t Resend Packets in Error • New Real Time Control Protocols • Developing New Internet Protocols • Use Multicasting • Packet Transmission • Humans Can Deal With 1ms Loss, So: • Break Audio Into 1 ms Chunks • Packets Too Small to Efficiently Send as 1ms • Send ms: 1, 4, 7, 10 in First Packet. 2, 5, 8, 11 in Second, etc. • If One Packet Is Lost • Lose 1ms Every 4, Instead of a Contiguous 4 ms Chunk

17. Streaming Multimedia Plug-Ins • Server Push (Data) • Server Updates HTML Page as Needed • Sports Scores, etc. • Audio • Almost There • Phone Quality Audio: 64kbps, 5 kbps Compressed • CD Quality Audio: 700kbps, 64kbps Compressed • RealAudio • Broadcast – AM Radio Quality • mp3 – Downloads of CD Quality Audio • Video • Bandwidth Still an Issue • 320x240x256 = 2.5 MB • Video Refreshes at 30 times per Second • 75 Mbps Required for Video • Still Pretty Crude • Compression Improving All the Time • Current: About 100x

18. Other Common Plug-Ins • Adobe Acrobat • PDF Files – Portable Document Format • Portable Distribution of “Printed” Documents • Allows Links, Some Text Search Capabilities • Viewable/Printable on Multiple Platforms • Author Can Restrict Access (e.g. Restrict Printing) • Proprietary Format • Viewers are Freeware

19. VRML • Virtual Reality Modeling Language • 3-D “Equivalent” of HTML • Standalone Browsers or Plug-Ins • Netscape, IE Make Plug-Ins Available • .wrl Extension. MIME type: x-world/x-vrml • Web 3D Consortium • http://www.web3d.org

20. Development Environments • Target Customer • Novice – (Hide HTML From User) • Experienced Developer – Make Process More Efficient • HTML Editors • Tag Editors • Graphical WYSIWYG Editors • Validation • Site Management • Macros/Pre-Processor’s/”Compilers” • Shorthand For More Complex Tags • Typically Use Custom Tags • GUI Development Environment • Conversion Tools • Convert Pages Designed in Other Environment Into HTML • E.g. Microsoft Office

21. Common Development Environments • Microsoft Frontpage • Novice Target • Hides Internals From User • Netscape Navigator Gold • Adobe PageMill • Dreamweaver • Macromedia Flash

22. Cookies Revisited • Cookies Are Name Value Pairs • Passed in the HTTP Header • Cookies Have Associated Expiration • Session (Default) • Date / Time • Associated With a URL Path, Not a Page! • Allows Passing Parameters Between Web Pages • Thus Cookies are Used to Provide State Information to a Stateless Protocol

23. Cookie Jar • Cookie Storage Internet Explorer c:\windows\cookies Each Has its Own FileNetscape Navigator cookies.txt (all kept in the file) • Limits • 20 Cookies • 4K Per Name/Value Pair

24. More Cookies • Cookies are Traditionally Set By Server • Set-Cookie • Browser is Responsible For Maintaining Them • Stored On Client’s Computer • Passed to Server When Web Site is Revisited • HTTP-Cookie • Cookie Attributes • Name – The Name of the Cookie • Subsequent References to Same Name Overwrites Cookie Attributes • Value – The Value of the Cookie Identified by Name • Expiration – When the Cookie Expires • No Date Specified – Cookie Expires at End of Session • Past Date/Time – Delete the Cookie • Future Date/Time – Delete the Cookie After This Date Example

25. Cookie Bits • Example Cookie • Set-Cookie: tollhouse=favorite;expires=Thursday, 16-Mar-2000 00:00:00 GMT;path=“” • Note That Date Must Follow This Format: • Weekday, DD-MMM-YYYY HH:MM:SS GMT • RFCs specify GMT as the mechanism for handling time problems on the Internet • HTTP-Cookie Only Sends Name/Value Pair

26. Cookies - JavaScript • Cookies Can be Set in JavaScript • document.cookie = “ “ • Use Date.toGMTString() to set expiration date • E.g. document.cookie = “version=1.0; ” + “expires=“ + edate.toGMTString(); • To Read a Cookie Value in JavaScript var allcookies= document.cookie; var pos = allcookies.indexOf(“version=“); if (pos != -1) { var start = pos +8; var end = allcookies.indexOf(“;”,start); if (end == -1) end = allcookies.length; var value = allcookies.substring(start,end); vervalue = unescape(value); }

27. Cookie Structure • Path Information • Default is to Send Cookie to Any URL in the Same Directory or any Subdirectory of the Page Which Set Cookie • Path Attribute Can Request That Cookie Be Sent to All URLs in Path (and its Subdirectories) • Only Paths That are a Prefix of Current URL are Allowed • If Cookies Overlap, All are Sent. • Ordered by Most Specific to Least Specific Match • Domain Attribute – Allows Cookies to Be Shared Across Sites • Must Be Part of Same Domain • E.g. boston.brandeis.edu and lab.brandeis.edu are part of the same domain but may be different servers • Secure – Only Sends Cookie If Secure Protocol is Used (e.g. SSL)

28. Security Issues • Protections: • Cookie Can Only Store Information Already Known to Server • Can’t Access Hard Disk, etc. • Data Only – Not Executed by Client Machine • Data Can’t Be Shared Across Sites • Concerns: • Of Course This Assumes That Browser Follows the Rules • Browser Can Store Sensitive Information • E.g. If Server Doesn’t Set Secure Tag, a Credit Card # May Be Passed in Clear to Another Page in Same Path • “Invisible” to Users • Paths Are Not Always Obvious • E.g. Multiple Sites Receive Graphics From DoubleClick Server • DoubleClick Can Now Gather “Cross-Site” Information • Zealous privacy folks advocate turning off cookies