Internet Technologies

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Presentation on "Overview of Internet Technologies and
Web 2.0" on 2nd of Feb 2009 during STC on INTERNET (2nd of Feb.2009 to 06th of Feb 2009) at NATIONAL INSTITUTE OF TECHNICAL TEACHERS’ TRAINING AND RESEARCH CHANDIGARH

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Internet Technologies

  1. 1. Overview Of Internet Technologies & Web 2.0 NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  2. 2. The Internet worldwide collection of computer networks 1969: ARPA (Advanced Research Projects Agency) NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  3. 3. Military project: that would survive a nuclear war Government agencies and certain educational centers ARPANET grew slowly (70's and 80's) NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  4. 4. Accomplished the truly monumental task Building blocks of this new, open, modular conglomeration of networks NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  5. 5. The various protocols (IP, TCP, DNS, POP, and SMTP) took shape over the years, and by the time the World Wide Web (HTML and HTTP) was created in the early 90's, this "Internet" had become a fully functional, fairly robust NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  6. 6. system of network - communication, able to support this new pair of protocols which eventually turned the Internet into a household word NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  7. 7. Web is not Internet; it is only one type of Internet - application, and one set of protocols among a great many which were in use for over a decade before the Web entered into the public awareness NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  8. 8. The Web is a subset of the Internet Email is not a part of the Web, and neither are newsgroups, although Web designers have developed web sites through which users, the world over, NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  9. 9. commonly access both of these much older forms of Internet media NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  10. 10. Email It is convenient and efficient way to send a message Send bills, eliminate phone calls, provide services without ever having contact. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  11. 11. Creates an impersonal environment Excessive involvement used to be "Text-only" NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  12. 12. History Of Email Experiment by the military to be able to send to and from the battlefield NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  13. 13. st 1 email (1972) Ray Tomlinsin Mail program: for Tenex operating system Heliomedia: The mail program; SNDMSG; READMAIL NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  14. 14. MAIL and MLFL (1972) were added to the FTP program and provided standard network transport capabilities for email transmission Early 1980's: more efficient SMTP protocol was NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  15. 15. developed. Among other improvements, SMTP enabled sending a single message to a domain with more than one addressee, after which the local server would locally copy the message to each recipient NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  16. 16. In 1993, America Online and Delphi started to connect their proprietary email systems to the Internet 1965: multiple users of mainframe computer NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  17. 17. Quickly extended to become network e-mail st 1 e-mail (1971) PCs: offline readers NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  18. 18. few standards: delete, backspace keys, text to "wrap around" Eudora: 1988 POP (or Post Office Protocol) NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  19. 19. With the World Wide Web, email started to be made available with friendly web interfaces NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  20. 20. Routing Email based entirely on the destination address username @ domain NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  21. 21. Email client will deliver outbound messages to their local mail server using SMTP. The local mail server then performs a DNS lookup to find the 'MX' (mail exchanger) records for the recipient's NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  22. 22. domain name. These MX devices are the designated mail servers for all email addresses within that domain The local server then attempts an SMTP connection to each of the MX servers in order of NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  23. 23. priority, until a connection is successful. It forwards the message to the remote server and ends the connection. The remote mail server then either repeats this process, forwarding the message NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  24. 24. closer to the intended recipient, or may deliver the message directly to the recipient. Before SMTP protocol, email was delievered using the NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  25. 25. UUCP (Unix-to-Unix Copy Protocol). In the early days of SMTP, before Spam became a massive problem on the Internet, it was possible to manually define the route that NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  26. 26. an email message was to take. This was done by appending multiple "@domain" entries to a recipient address. For example: NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  27. 27. user@domain1.com@domain 2.com@domain3.com A message with this recipient address would be routed first to the mail server for domain3.com, then to the mail server for domain2.com, then NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  28. 28. finally to the mail server for domain1.com where it would be delivered to the local user Due to anti-relaying restrictions now in place on Internet-accessible mail NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  29. 29. servers, this is generally no longer possible new anti-spam feature "Challenge/Response System", sends a link, or a word-verification page NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  30. 30. Domain Names The Domain Name System, (DNS):Core feature Distributed database that handles the mapping between NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  31. 31. host names and numerical Internet addresses. An automated phone book Reverse mapping: query for a name for 202.164.53.112 NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  32. 32. Punycode-based IDNA system, approved by ICANN (Internet Corporation for Assigned Names and Numbers: 1998) and adopted by some registries Flavors of DNS software: NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  33. 33. •BIND (Berkeley Internet Name Domain) •DJBDNS (Dan J Bernstein's DNS implementation) •MaraDNS NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  34. 34. •NSD (Name Server Daemon) •PowerDNS 13 "root servers" WHOIS database: for most TLDs a basic WHOIS is held NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  35. 35. by ICANN, detailed WHOIS maintained by the domain registry Modern OSs and network applications contain resolver for interrogating DNS services. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  36. 36. dig, nslookup, whois dig gndec.ac.in gndec.ac.in. 202.164.53.112 NS ns2.comeconnect.com. NS ns1.comeconnect.com. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  37. 37. nslookup gndec.ac.in Name: gndec.ac.in Address: 202.164.53.112 whois gndec.ac.in Domain Name:GNDEC.AC.IN NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  38. 38. Created On:31-Oct-2003 Last Updated On:31-Oct-2007 Expiration Date:31-Oct-2009 05:00:00 UTC NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  39. 39. Sponsoring Registrar:Ernet Registrant Name:Guru Nanak Dev Engineeing College Registrant Email:sainijasbir@yahoo.com NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  40. 40. Name Server: NS2.COMECONNECT.COM NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  41. 41. Usenet Usenet is a "network" of newsgroup servers (often run by ISPs) working together. Once connected to Usenet one can find everything. One NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  42. 42. bad thing about Usenet is that it is often used to distribute illegal digital (warez) content like mp3, cracked software, or cracked video games. In most cases Usenet is the first step in the life of warez. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  43. 43. Unfortunately this has caused many newsgroup servers to block access to known warez newsgroups. Usenet providers normally charge money for access but many ISPs have newsgroup NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  44. 44. servers running that their customers can access for free. So if you would like to check out Usenet first call your ISP and find out if they have a newsgroup server running NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  45. 45. History Of Usenet 1979 software to post announcements Duke st University; Steve Bellovin: 1 NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  46. 46. UNIX-based “news” software for the system “netnews” Usenet is bulletin board software where users with the correct software can read and post messages. URL’s that NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  47. 47. begin with news refer to Usenet groups. The NNTP or Network News Transport Protocol is the transportation system that sends out the Usenet messages. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  48. 48. IRC Internet Relay Chat: chat protocol NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  49. 49. Technology Of IRC is a real-time text-based multi- user communication protocol specification and NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  50. 50. implementation, which relays messages between users on the network (1988). Official specification (1993) "RFC 1459: Internet Relay Chat Protocol" NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  51. 51. A client logged into one network can communicate only with other clients on the same network, not with clients on other networks. Each network is composed of one or more IRC servers. An IRC client is a program that NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  52. 52. connects to a given IRC server in order to have the server relay communications to and from other clients on the same network but not necessarily the same server NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  53. 53. Messages on IRC are sent as blocks. That is, other IRC clients will not see one typing and editing as one does so. One creates a message block and transmits that block all at once, which is received by the server and based on the NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  54. 54. addressing, delivers it to the appropriate client or relays it to other servers so that it may be delivered or relayed again Once connected to a server, addressing of other clients is achieved through IRC NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  55. 55. nicknames. A nickname is simply a unique string of ASCII characters identifying a particular client. Although implementations vary, restrictions on nicknames usually dictate that they be composed only of characters NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  56. 56. a-z, A-Z, 0-9, underscore, and dash. IRC channels: Any communication sent to that channel is then seen by the client. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  57. 57. IRC is not P2P protocol, but does have some extensions (DCC: Direct Client Connect and CTCP: Client To Client Protocol) that support text and file transmission directly from client to client without any relay at all. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  58. 58. Using Internet Relay Chat To use Internet Relay Chat, you need to do the following: •Choose and install an IRC client. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  59. 59. •Find the channel discussing the topic of your interest •Find the server at which the channel is located. You can be directed to both the server and the channel by the website of a project NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  60. 60. •Connect to the server using the client, using a nickname of your choice •Connect to the channel By default, the conversations using IRC are public NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  61. 61. To have a private conversation with a user in the channel, type "/query nickname" For private chat, join an non- existent channel, and then allow joining only by invitation NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  62. 62. IRC clients ChatZilla: An add-in for Firefox. IRSSI: Has a text-only user interface. MIRC: Good for beginners. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  63. 63. XChat Windows Pidgin, Miranda, Trillian: multi-protocol clients Opera: A web browser with integrated IRC client NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  64. 64. Protocols Specification of a set of rules for a particular type of communication Different protocols often describe different aspects of a NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  65. 65. single communication; taken together, these form a protocol stack. The terms "protocol" and "protocol stack" also refer to the software that implements a protocol. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  66. 66. Most recent protocols are assigned by the IETF for Internet communications, and the IEEE, or the ISO organisations for other types. The ITU-T handles telecommunications protocols and formats. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  67. 67. Index page for network protocols and protocol layers, categorised by the nearest matching layers of the OSI seven layer model NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  68. 68. Common Internet Protocols Include TCP/IP(Transmission Control Protocol/Internet NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  69. 69. Protocol), UDP/IP (User Datagram Protocol/Internet Protocol), HTTP(HyperText Transfer Protocol) and FTP(File Transfer Protocol). TCP/IP is a stream protocol. This means that a connection NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  70. 70. is negotiated between a client and a server. Any data transmitted between these two endpoints is guaranteed to arrive, thus it is a so-called lossless protocol. Since the TCP protocol can only connect two endpoints, it is NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  71. 71. also called a peer-to-peer protocol. HTTP is the protocol used to transmit all data present on the World Wide Web. This includes text, multimedia and graphics. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  72. 72. HTTP is the protocol used to transmit HTML, the language that makes all the fancy decorations in browser. It works upon TCP/IP. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  73. 73. Routing A route is the path that data takes when travelling through a network from one host to another. Routing is the process by which the path, or NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  74. 74. some subset of it, is determined. One of the characteristic features of the Internet, as compared to other network architectures, is that each node that receives a packet will typically determine for itself what the next step in NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  75. 75. the path should be. IP routing decisions are generally made based on the destination of network traffic. When an IP packet is sent from a node on the network, it will consult its routing table to determine the next hop device that the traffic NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  76. 76. should be sent to, in order for it to reach its final destination. When node receives a packet on interface eth0 which has a destination of 216.239.59.114, it will consult the table and see that it should send it through the default interface, NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  77. 77. the host x.y.z, which is on interface ppp0. The routing table is constructed from a combination of statically defined routes and those learned from dynamic routing protocols. Statically defined routes may be declared at NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  78. 78. system boot time, or via a command line interface. They will generally include the following parameters: •Destination - this may be either a single host, or a NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  79. 79. network (in that case N/W mask is also required) •Gateway - the device to which traffic with the defined destination should be sent NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  80. 80. Static routes may also include the following parameters: •Interface - the interface through which the traffic to a destination must be sent. (Most OSs can determine this automatically) NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  81. 81. •Metric - the number of 'hops' away that the gateway is from this host. For a gateway that resides on a directly connected network, the metric is '1' NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  82. 82. The default route is a special case of a statically defined route. It is the route of last resort. All traffic that does not match another destination in the routing table is forwarded to the default gateway. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  83. 83. Dynamic routing protocols allow network attached devices to learn about the structure of the network dynamically from peer devices. This reduces the administrative effort required to implement and change NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  84. 84. routing throughout a network. Some examples of dynamic routing protocols are: •RIP (Routing Information Protocol) NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  85. 85. •OSPF (Open Shortest Path First) •ISIS (Intermediate system to intermediate system) •BGP (Border Gateway Protocol) NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  86. 86. •IGRP (Interior Gateway Routing Protocol) ISIS and OSPF are link-state protocols, meaning each node is part of the same zone, will know the state of all the link in the mesh. Due to the NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  87. 87. exponential number of link in a mesh, these protocols are used for small mesh such as an ISP national backbone. RIP is usually used to easily announce customer's routes in a backbone. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  88. 88. BGP is used as an external routing protocol to exchange routes with other entities. ISP use BGP extensively to trade their routes. It can also be used to carry customers routes across a network, in a MPLS backbone for example. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  89. 89. Web Hosting When someone sets up a server and hooks it up to the Internet, the files on the server become accessible over the Internet. Web NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  90. 90. Hosting is your personal space on that server. Web hosting is your own storage on the Internet. If you upload HTML files, you'll have a website. If you upload .ZIP files, you'll have a NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  91. 91. download area. It's up to you what you do with it, but Web hosting is online storage. Most companies own their own servers these days, but some still pay for web hosting. Let's say Harbhajan decides NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  92. 92. he wants to sell his paintings online. He purchases web hosting, and sets up a website. Ajay, on the other hand, wants to set up a forum system. he purchases web hosting and NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  93. 93. installs the forums. If you know how, you can make an entire website, or put any files you want, online, via your web hosting. In addition, over the last few years hundreds of "web site NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  94. 94. software" have been written that, when installed onto your hosting account, give you an immediate web site. When looking for a web site software, it's important to consider the software license. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  95. 95. If you stick with FOSS when selecting your web site software, you will have the advantage of new software releases that are made available free of charge. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  96. 96. The Web The World Wide Web (the "Web" or "WWW" for short) is a hypertext system that operates over the Internet. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  97. 97. S/W program: web browser Information: documents or web pages The first web browser named Mosaic was developed in the early 1990s. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  98. 98. Popular web browsers: Internet Explorer Firefox Netscape. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  99. 99. URLs, HTTP, HTML Uniform Resource Locator (URL): NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  100. 100. Specifies how each page of information is given a unique "address" at which it can be found Hyper Text Transfer Protocol (HTTP): Specifies how the NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  101. 101. browser and server send the information to each other Hyper Text Markup Language (HTML) is a method of encoding the information so it can be displayed on a variety of devices. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  102. 102. World Wide Web Consortium: Develops and maintains these standards and others that enable computers on the Web to effectively store and communicate all kinds of information. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  103. 103. Beyond Text Viola (1992) added the ability to display graphics as well. Mosaic for X (1993) sparked a tremendous rise in the popularity of the Web NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  104. 104. Additional features such as dynamic content, music and animation can be found in modern browsers Issue: the web as seen by Netscape is not at all the NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  105. 105. same as the web seen by Internet Explorer. Real-time web-based services such as webcasts, web radio and live web cams. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  106. 106. Java & Javascript Sun Microsystems' Java: Enabled web servers to embed applets; faster and richer user interaction NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  107. 107. JavaScript: Scripting language developed for Web pages. Document Object Model (DOM) NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  108. 108. Hyper-text promote non- hierarchical and non-linear way of expression and thinking. It does not have a linear order from the beginning to the end. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  109. 109. History Of The Web The Web grew out of a project at CERN (1989): Make it easier to share research NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  110. 110. papers among colleagues. Enquire Within Upon Everything: Berners-Lee released files describing his idea for the "World Wide Web" onto the Internet on August 6, 1991 NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  111. 111. HTML Static pages; Dynamic, interactive As a markup language: it provide a set of general rules that suggest how content NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  112. 112. should look when rendered. A markup language doesn't dictate the methods used to display the content, nor does it have fore knowledge of the target context, so this control is imprecise. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  113. 113. Early tools: primitive Publishing HTML-formatted documents on the Internet via the World Wide Web HTML is a subset of the Standard Generalised Markup NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  114. 114. Language (SGML), which is an Int. Std. (ISO 8879) published in 1986 as a format for structuring and marking up documents. An important addition to HTML was the inclusion of support for hypertext (linked information). NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  115. 115. Embedded Technologies Stand-alone programs and plugins that extend the normal functionality of a web page. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  116. 116. Java, Shockwave Flash, audio and video players are all examples of embedded technologies that can assist creating a web site NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  117. 117. Proxy Servers Provide a cache of items available on other servers (slower, expensive, unavailable from the local network) NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  118. 118. Squid Apache's mod_proxy module NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  119. 119. Search Engine Computer software: search data in the form of text or a ˙ database for specified information. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  120. 120. Search engines normally consist of spiders (bots) which roam the web searching for links and keywords. They send collected data back to the indexing software which categorises and adds NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  121. 121. the links to databases with their related keywords. Before 1993 the term search engine never existed. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  122. 122. Web Advertising Static images, animated GIFs, and Flash Animation Banners, Pop-up, intro pages NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  123. 123. A banner can be an image, animated gif, flash video or plain text A Pop-up causes a new browser window to open and displays a webpage that can NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  124. 124. contain text, images and flash. Intro Pages to websites usually have a flash or gif animation to introduce a company, their services or Products. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  125. 125. Ad servers: Central ad server. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  126. 126. Remote Access Allows you to access one computer from another. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  127. 127. Telnet A protocol designed to remotely access computers in a client-server fashion. SSH (Secured SHell) NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  128. 128. Uses SSH is actually so much more than just a way to access a remote shell securely. Scp: copy files between machines; allows recursive NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  129. 129. copies; copy a file from a remote host to a remote host. scp: user@host.com:~/files/ . Encrypt the transport of any data from one machine to another. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  130. 130. Port forwarding: . This allows you 'redirect' communication to and from a local application through SSH to another host. So, with SSH you can secure otherwise insecure communications over an encrypted 'tunnel'. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  131. 131. Using SSH The secure shell client is conveniently called ssh. ssh user@host Using SFTP NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  132. 132. SFTP merely works like FTP, sftp user@host Using SCP scp FILE_PATH user@host:REMOTE_PATH NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  133. 133. Copy from a remote host scp user@host:rPath l_Path scp -r user@host:dirName destination_dir SSH as a Proxy NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  134. 134. If you can make an SSH connection, you can (most likely) use that connection as a SOCKS proxy, without any extra setup on the remote computer. Traffic is tunneled securely through the SSH connection. If you are on an NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  135. 135. unsecured wireless connection, you can use this to effectively secure all your traffic from snooping. You can also use this to bypass IP restrictions, because you will appear to be connecting from the remote computer. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  136. 136. VNC Virtual Network Computing (VNC) is a remote desktop protocol to remote control another computer. VNC is used to transport the desktop NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  137. 137. environment of a graphical user interface from one computer to a viewer application on another computer on the network. There are clients and servers for all most all GUI OSs. The VNC protocol allows for NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  138. 138. complete platform independence. A VNC viewer on any operating system can connect to a VNC server on any other operating system. It is also possible for multiple clients to connect to a VNC server at the same time. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  139. 139. Popular uses of the technology include remote tech support, and accessing your files on your work PC while at home or even on the road. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  140. 140. There is even a Java viewer for VNC, so you can connect to a VNC server from your web browser without installing any software. The original VNC code is open source, as are many of NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  141. 141. the flavours of VNC available today. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  142. 142. How It Works VNC is actually two parts, a client and a server. A server is the machine that is sharing its screen, and the client, or viewer is the program that is NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  143. 143. doing the watching and interacting with the server. VNC is actually a very simple protocol and is based on graphic primitive, "Put a rectangle of pixel data at a given x,y position". What this means is VNC takes small NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  144. 144. rectangles of the screen (actually the framebuffer) and transports them from the server to the client. This in its simplest form would cause lots of bandwidth to be used, and hence various methods have been invented to make NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  145. 145. this process go faster. There are now many different 'encodings' or methods to determine the most efficient way to transfer these rectangles. The VNC protocol allows the client and server to negotiate which encoding it NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  146. 146. will use. The simplest and lowest common denominator is the raw encoding method where the pixel data is sent in left-to-right scanline order, and after initial setup, then only transfers the rectangles that have changed. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  147. 147. Web 2.0 Describes the changing trends in the use of World Wide Web technology and web design that aim to enhance creativity, NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  148. 148. communications, secure information sharing, collaboration and functionality of the web. Web 2.0 concepts have led to the development and evolution of web culture NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  149. 149. communities and hosted services, such as social- networking sites, video sharing sites, wikis, and blogs. O'Reilly Media Web 2.0 conference in 2004. Although NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  150. 150. the term suggests a new version of the World Wide Web, it does not refer to an update to any technical specifications, but rather to changes in the ways software developers and end-users NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  151. 151. utilise the Web. According to Tim O'Reilly: Web 2.0 is the business revolution in the computer industry caused by the move to the Internet as a platform, and an attempt to NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  152. 152. understand the rules for success on that new platform. Tim Berners-Lee, inventor of the World Wide Web, has questioned whether one can use the term in any meaningful way, since many NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  153. 153. of the technological components of Web 2.0 have existed since the early days of the Web. Uses of Web as a platform. Don't fight the Internet, encompasses the essence of NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  154. 154. Web 2.0 — building applications and services around the unique features of the Internet, as opposed to expecting the Internet to suit as a platform (effectively "fighting the Internet"). NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  155. 155. Web had become a platform, with software above the level of a single device, leveraging the power of "The Long Tail," and with data as a driving force. An architecture of participation where users can NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  156. 156. contribute website content creates network effects. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  157. 157. Characteristics Web 2.0 websites allow users to do more than just retrieve information. They can build on the interactive facilities of "Web 1.0" to provide "Network NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  158. 158. as platform" computing, allowing users to run software-applications entirely through a browser. Users can own the data on a Web 2.0 site and exercise control over that data These sites may have an "Architecture of NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  159. 159. participation" that encourages users to add value to the application as they use it. Web 2.0 sites often feature a rich, user friendly interface based on Ajax, OpenLaszlo, Flex or similar rich media. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  160. 160. Technology Overview server software, content- syndication, messaging- protocols, standards-oriented NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  161. 161. browsers with plugins and extensions, and various client applications. Web 2.0 websites typically include some of the following features/techniques. (acronym SLATES): NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  162. 162. •Search: keyword search •Links: guides to important pieces of information. The best pages are the most frequently linked. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  163. 163. •Authoring: In wikis, the content is iterative in the sense that the people undo and redo each other's work. In blogs, content is cumulative in that posts and comments of individuals are accumulated over time. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  164. 164. •Tags: categorisation of content •Extensions: automation of some of the work and pattern matching by using algorithms e.g. amazon.com recommendations. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  165. 165. •Signals: the use of RSS technology to notify users with any changes NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  166. 166. Usage Higher Education Government 2.0 Public diplomacy NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  167. 167. Web 2.0 initiatives have been employed in public diplomacy for the Israeli government. The country is believed to be the first to have its own official blog, MySpace page, YouTube channel, Facebook NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  168. 168. page and a political blog. The Israeli Ministry of Foreign Affairs started the country's video blog as well as its political blog. The Foreign Ministry also held a microblogging press conference via Twitter about NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  169. 169. its war with Hamas, with Consul David Saranga answering live questions from a worldwide public in common text-messaging abbreviations. The questions and answers were later posted on NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  170. 170. Israelpolitik.org, the country's official political blog. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  171. 171. Web-based Applications And Desktops Ajax has prompted the development of websites that NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  172. 172. mimic desktop applications, such as word processing, the spreadsheet, and slide-show presentation. WYSIWYG wiki sites replicate many features of PC authoring applications. Still other sites perform NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  173. 173. collaboration and project management functions. mimic the user experience of desktop application able to run within any modern browser. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  174. 174. XML And RSS Protocols which permit syndication include RSS (Really Simple Syndication — also known as "web syndication"), RDF (as in RSS NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  175. 175. 1.1), and Atom, all of them XML-based formats. Observers have started to refer to these technologies as "Web feed" as the usability of Web 2.0 evolves and the NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  176. 176. more user-friendly Feeds icon supplants the RSS icon. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  177. 177. Web APIs Machine-based interaction, uses two main approaches to Web APIs, which allow web- based access to data and functions: NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  178. 178. REST and SOAP. •REST (Representational State Transfer) Web APIs use HTTP alone to interact, with XML (eXtensible Markup Language) or JSON payloads; NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  179. 179. •SOAP involves POSTing more elaborate XML messages and requests to a server that may contain quite complex, but pre- defined, instructions for the server to follow. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  180. 180. Often servers use proprietary APIs, but standard APIs (for example, for posting to a blog or notifying a blog update) have also come into wide use. Most communications through APIs involve XML or JSON payloads. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  181. 181. The argument exists that "Web 2.0" does not represent a new version of the World Wide Web at all, but merely continues to use so- called "Web 1.0" NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  182. 182. technologies and concepts. Techniques such as AJAX do not replace underlying protocols like HTTP, but add an additional layer of abstraction on top of them. Many of the ideas of Web 2.0 had already been featured in NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  183. 183. implementations on networked systems well before the term "Web 2.0" emerged. Amazon.com, for instance, has allowed users to write reviews and consumer guides since its launch in 1995, in a form of self- NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  184. 184. publishing. Amazon also opened its API to outside developers in 2002. NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com
  185. 185. Thanks NITTTR:Chd STC: Internet: Feb 2, 2009 hs.raiandrai.com

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