IT_Internet_the gaint wide Area Network.pptx

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1. INTERNET TECHNOLOGIES

2. What is Internet The Internet is a global network of networks that enables computers of all kinds to directly and transparently communicate and share services throughout the world. (or) The Internet is defined as the globally distributed network of networks that consist of millions of private,public,academic, business, and government networks, which are linked by an extensive range of electronic,wireless,and optical networking technologies.

3. History of Internet In 1960’s In 1969 the precursor of Internet is born: ARPAnet. ARPA = Advanced Research Projects Agency sponsored by the American Department of Defense (DOD). Designed to connect military research centers. Problem: ARPAnet could connect only networks of the same type.

4. In 1970, ARPA starts developing the Transmission Control Protocol / Internet Protocol (TCP/IP), a technology for connecting networks of different types. Other networks appear, such as CSNET and BITNET. In 1982 the word internet started. 1986: First “ freenet ” created in Case Western Reserve University 1991: US government allowed business agencies to connect to internet. Now all peoples can connect to internet and improve their life and work quality. The internet support various aspects in our life

5. Types of Interconnection Networks Local Area Networks (LANs) : A Local Area Network (LAN) is a network that is used for communicating among computer devices, usually within an office building or home. Though it is limited in size, Maximum interconnect distance few kilometers to few tens of kilometers, it is fast, with speeds from 10 Mbps to 10 Gbps with minimal infrastructure requirements, low cost, and high security. LANs can be either wired or wireless Example (most popular): Ethernet, with 10 Gbps over 40Km

6. Metropolitan Area Network (MAN) : A metropolitan area network (MAN) is a network that connects computers within a metropolitan area, which could be a single large city, multiple cities and towns, or any given large area with multiple buildings. A MAN is larger than a  local area network (LAN)  but smaller than a  wide area network (WAN) . MAN is made up of interconnected LANs.  The main purpose of a MAN is to connect different LANs in a city to share resources and exchange data, as well as to provide internet access to users.

7. Metropolitan Area Network (MAN)

8. Wide area networks: WAN covers a large geographic area such as country, continent or even whole world. WANs are used to interconnect the enterprise LAN to remote LANs in branch sites and telecommuter sites. It is two or multiple LANs connected using devices such as routers, or gateways, which enable them to share resources. Many millions of devices interconnected Max distance: many thousands of kilometers Example: ATM (asynchronous transfer mode)

9. A WAN is owned by a  service provider . A user must pay a fee to use the provider’s network services to connect remote sites. WAN service providers include carriers, such as a telephone network, cable company, or satellite service. Service providers provide links to interconnect remote sites for the purpose of transporting data, voice, and video.

10. Wide area networks:

11. Server – based Networks ( Client / Server Network): A client-server network is a form of internet network that consists of a single central computer functioning as a server and directing several other computers, referred to as clients. Clients have an active role and initiate a communication session by sending requests to servers for some resources or services. Clients can communicate with servers only; they cannot see each other. Servers have a passive role handles the requests by clients and sends the response ( results) back to clients. One server generally supports numerous clients

12. Client / Server Network

13. Peer – to – Peer Network : A peer-to-peer (P2P) network is group of computers. In the P2P network architecture, all computers have equivalent capabilities and responsibilities and either party can initiate a communication session and sharing files within the group. There is no central location for authenticating users, storing files, or accessing resources.

14. There are two types of P2P networks: Pure P2P Network Hybrid P2P Network. Pure P2P Network : In this kind of P2P network, not a dedicated server, is considered, where each peer in the network plays an equal role.  Hybrid P2P Network : The functionality of a hybrid P2P network is like a client-server network. In this type of networking, a centralized peer is defined that accomplishes various activities as servers perform. It retains all information on the connected system and replies to the requests asking for that specific information.

15. Hybrid P2P Network :

16. Communication on the Internet The Internet is a global collection of computer networks that are linked together by devices called routers and use a common set of protocols for data transmission known as TCP/IP (transmission control protocol / Internet protocol). The primary purpose of the Internet is to facilitate the sharing of information. The Internet is a worldwide network of networks.

17. There are several ways to communicate over the internet. Email Instant Messaging Social Networking Forums Audio Conferencing Video Conferencing

18. Email: Electronic mail (E-mail) is one of the most famous internet services. In earlier days of the internet, electronic mail sent short and consist only text messages. People could exchange messages in a fast way. Now-a-days in e-mail, messages can consist text, audio, images and video. It provides facility to send one message to one or more recipients. Users can compose, read and send messages through E-mail.

19. Instant Messaging : To send real time messages from one user to another, Instant Messaging or IM is used. One user types a message that is conveyed over a network and received by the other user. A specific program (i.e. Yahoo Messenger or Windows Live Messenger etc.) is used for Instant messaging between two or more people.

20. Social Networking : Social networking is an important way of communication. Users can connect and communicate to each other using it. Users can make new friends, find users of similar interest and reconnect with old friends on Social networking websites or applications. Firstly, users need to create a profile on these websites and customize the privacy policy according to their needs (i.e. who can see his/her photos, send friend request or post on his/her timeline etc.). Ex: Facebook , Myspace , Twitter, Instagram etc. are the popular social networking applications.

21. Audio Conferencing : Audio conferencing is used to connect multiple called parties which are located at different locations on a single audio conference call. Two or more people can be involved in an audio conference call at the same time. Audio conference call can be conducted either through the internet or telephone line. Devices (i.e. phones or computers) which allows sounds to be sent and received are used for audio conferencing. Audio conferencing needs speakers and microphones both. For listening purpose, only speakers are needed. But for speaking purpose microphones are also required

22. Video Conferencing : People are allowed to communicate with one another in real time interactive audio/video. Videoconferencing is an example of real time interactive audio/video in which people are allowed to communicate visually and orally. video/audio system which allows two or more humans to communicate with each other which is located at different places. Videoconferencing is usually used in business meetings, distance learning and web-based courses. videoconferencing is useful for employee training, group work or to introduce a new product or service.

23. Formus : An online discussion site where people can do conversations in the form of posted messages is known as an Internet Forum or Message Board. Ex: Reddit Reddit is basically a large group of forums in which registered user can talk about almost any thing you can imagine, from news, to pop culture,to technology, to comics.

24. Protocal Layering: Two Popular models: OSI Model ( open system Interconnection ) TCP /IP Model ( Transmission control protocol) The OSI model was considered the primary architectural model for inter-computer communications and described how information or data made its way from application programs (such as spreadsheets) through a network medium (such as wire) to another application program located on another network.

25. OSI reference model

26. Physical Layer The lowest layer of the OSI reference model is the physical layer. It is responsible for the actual physical connection between the devices. The physical layer contains information in the form of  bits.  It is responsible for transmitting individual bits from one node to the next.  Data Link Layer The data link layer is responsible for the node-to-node delivery of the message. The main function of this layer is to make sure data transfer is error-free from one node to another, over the physical layer.

27. Network Layer : The network layer works for the transmission of data from one host to the other located in different networks. Transport Layer  It is responsible for the End to End Delivery of the complete message. The transport layer also provides the acknowledgment of the successful data transmission and re-transmits the data if an error is found. Session Layer This layer is responsible for the establishment of connection, maintenance of sessions, and authentication, and also ensures security.

28. Presentation Layer : The presentation layer is also called the  Translation layer . The data from the application layer is extracted here and manipulated as per the required format to transmit over the network.  Encryption/ Decryption :  Data encryption translates the data into another form or code. The encrypted data is known as the cipher text and the decrypted data is known as plain text. A key value is used for encrypting as well as decrypting data. Application Layer This layer also serves as a window for the application services to access the network and for displaying the received information to the user.  Example: Application – Browsers, Skype Messenger, etc. 

29. TCP/IP Model : TCP/IP model, it was designed and developed by the Department of Defense ( DoD ) in the 1970s and is based on standard protocols. It stands for Transmission Control Protocol/Internet Protocol. The  TCP/IP model  is a concise version of the OSI model. It contains five layers. The layers are: Application Layer Transport Layer(TCP/UDP) Network/Internet Layer(IP) Data Link Layer (MAC) Physical Layer

30. Layers in TCP/IP OSI Model Application  Application Presentation Session Transport Transport Network/Internet Network Data-link Data-link Physical Physical

31. Application Layer:   This layer is analogous to the transport layer of the OSI model. It is responsible for end-to-end communication and error-free delivery of data. It shields the upper-layer applications from the complexities of data. Transport Layer: The Transport Layer is responsible for reliable source-to destination (end-to-end) delivery of the entire message. This layer is roughly equivalent to the Transport Layer in the OSI Reference as it provides end-to-end communication services. There are two primary Transport Layer protocols at present: TCP and User Datagram Protocol (UDP). TCP is a reliable connection-oriented protocol whereas UDP is a connectionless (datagram) protocol.

32. Network/Internet Layer: It defines the protocols which are responsible for the logical transmission of data over the entire network. The main protocols residing at this layer are as follows: IP –  stands for Internet Protocol and it is responsible for delivering packets from the source host to the destination host by looking at the IP addresses in the packet headers. IP has 2 versions: IPv4 and IPv6.  ICMP –  stands for Internet Control Message Protocol. It is encapsulated within IP datagrams and is responsible for providing hosts with information about network problems. ARP –  stands for Address Resolution Protocol. Its job is to find the hardware address of a host from a known IP address. ARP has several types: Reverse ARP, Proxy ARP, Gratuitous ARP, and Inverse ARP.

33.   Data Link Layer : It specifies how to organize data into frames and how to deliver a frame over a network. Its responsibility is the correct delivery of messages. Point-to-Point Protocol (PPP) framing and Ethernet IEEE 802.2 framing are two examples of data-link layer protocols. Physical Layer: Provides physical interface for transmission of information. Defines rules by which bits are passed from one system to another on a physical communication medium.

34. TCP/IP OSI Model The full form of TCP/IP is Transmission Control Protocol/ Internet Protocol. The full form of OSI is Open Systems Interconnection. It is a communication protocol that is based on standard protocols and allows the connection of hosts over a network. It is a structured model which deals which the functioning of a network. In 1982, the TCP/IP model became the standard language of ARPANET. In 1947, the OSI model was introduced by the International Organisation of Standardization (ISO). It comprises of four layers: Network Interface Internet  Transport  Application It comprises seven layers: Physical Data Link Network Transport Session Presentation Application It follows a horizontal approach. It follows a vertical approach. The TCP/IP is the implementation of the OSI Model. An OSI Model is a reference model, based on which a network is created. It is protocol dependent. It is protocol independent. OSI versus TCP/IP model .

35. Internet Working Through Router

36. A router is a hardware device and has the function of routing packets between networks. A router works at Layer 3 of the  OSI model  – the Network Layer. The network layer protocols determine which route is suitable from source to destination. This function of the network layer is known as routing. The network layer works for the transmission of data from one host to the other located in different networks. It also takes care of packet routing i.e. selection of the shortest path to transmit the packet, from the number of routes available. The sender & receiver’s IP addresses are placed in the header by the network layer. 

37. Routers replace the Ethernet MAC address of the source device with their own MAC address when they send a packet out an interface. When the response to that packet comes back, the new source of the packet is sending the response to the destination of the router. The router receives this, replaces the source address, changes the destination address to the original address, and sends the packet back to the original sender.

38. Internet protocol stack : There are five layers in the internet protocol stack. While sending a message, the message travels through each layer one by one, starting from the application layer.

39. The Internet Protocol stack (TCP/IP Protocol Suite) is based on the divide- and-conquer modus operand to define and use the architecture entailing communication (Application, Transport), interconnection (Network, Link), and distance (Physical). The role of each layer is as follows: Application layer : Application layer  is responsible for communication between applications running on two different end systems. We distinguish two categories of application layer protocols: user protocols that provide service directly to users, and support protocols that provide common system functions.

40. The protocols used at the application layer include: Hypertext Transfer Protocol (HTTP): for transferring HTML web documents File Transfer Protocol (FTP): for transferring files Simple Mail Transfer Protocol (SMTP): for transferring e-mail messages Domain Name System (DNS): for translation of human-friendly domain names into IP addresses

41. Transport layer :  It is responsible for the End to End Delivery of the complete message. The two important protocols used in the transport layer are: Transmission Control Protocol (TCP): for reliable and connection-oriented data transfer. TCP is a reliable protocol as it detects the error and retransmits the damaged frames. At the sending end, TCP divides the whole message into smaller units known as segment, and each segment contains a sequence number which is required for reordering the frames to form an original message. At the receiving end, TCP collects all the segments and reorders them based on sequence numbers.

42. User Datagram Protocol (UDP): for fast, unreliable, and connection-less data transfer. UDP consists of the following fields: Source port address:  The source port address is the address of the application program that has created the message. Destination port address:  The destination port address is the address of the application program that receives the message. Total length:  It defines the total number of bytes of the user datagram in bytes. Checksum:  The checksum is a 16-bit field used in error detection. UDP does not specify which packet is lost. UDP contains only checksum; it does not contain any ID of a data segment.

43. Network Layer: The  network layer  is responsible for transferring data from one system to another on the network.  The main protocol used at the network layer to transfer data is  Internet Protocol  (IP). This protocol makes use of IP addresses to identify each system connected to the internet. The two versions of IP protocol are as follows: IPv4 : widely used protocol for communication over the internet and uses a 32-bit IP address IPv6 : proposed to replace IPv4 with the IP addresses of 128-bits because 32-bit IP addresses will be insufficient with the high number of computers being connected to the internet Another protocol used at this layer for error-reporting is the  Internet Control Message Protocol  (ICMP). ICMP requests the sender to resend the data if the data is not received or received in the wrong order on the other end.

44. Link layer ( network interface ): When a packet is being transferred over the internet, several intermediate devices are between the two end systems. These devices may be routers, switches, or other computers. The  link layer  is responsible for communication between one device and its immediate neighbor. The link-layer is mostly implemented in the network adapter/network interface card (NIC), and technologies like Ethernet, Wi-Fi, token ring, etc., are associated with the link layer.

45. Physical layer : It Provides physical interface for transmission of information. Defines rules by which bits are passed from one system to another on a physical communication medium. It covers all the mechanical, electrical, functional, and procedural aspects for physical communication. Internet Addressing: An IP address is a unique global address for a network interface. It is 32-bit logical address, composed of four 8-bit fields, called octets. The address is represented in “dotted decimal notation” by grouping the four octets. Each octet represents a decimal number in the range 0–255 (since 255 is the maximum 8-bit binary number), i.e., the format of IP address is xxx.xxx.xxx.xxx , where each xxx is a number from 0 to 255. These are unique numbers and controlled by address registry. For example, 17.112.152.32 is the IP address for www.apple.com, for www.amazon.com it is 54.239.26.128

46. URL( Uniform Resource Locators ): Uniform Resource Locators (URL) specifies the Internet address of a file stored on a host computer (server), connected to the Internet. URLs are translated into numeric addresses using a DNS. When we type a URL, DNS translates the human-friendly URL into the computer-friendly IP address. Ex: DNS is responsible for translating “www.apple.com” into “17.112.152.32” whenever we type that into a browser address bar. A URL is made up of many parts. The generic anatomy of a URL is: protocol://domain name /path/filename Protocol: It specifies the transfer protocol that will be used for retrieval of desired resource. Examples include Hypertext Transfer Protocol (http), HTTP Secure Protocol (https), and File Transfer Protocol (ftp).

47. Domain name: The Domain name is also known as website name or host name. Path: It is the directory or the folder on the server. File name: It is the file name within that directory with an extension such as htm, html, php, and so on. For example: http://dtu.ac.in/Web/Academics/syllabus.php URL: Contains information about how to fetch a resource from its location. URLs always start with a protocol (http) and usually contain information such as the network host name (dtu.ac.in) and often a document path (/Academics/syllabus.php).

48. Accessing the Internet: Every computer connected to the Internet accesses the Internet through an Internet Service Provider (ISP). The ISP, in turn, may connect to a larger network such as a Network Service Provider (NSP) that provides backbone services to the Internet service provider. These connections are collectively known as Internet Backbone. The backbones carry Internet traffic around the world and meet at Network Access Points (NAPs). ISPs connect either directly to a backbone, or they connect to a larger ISP with a connection to a backbone. There are three ingredients needed to access the Internet from a laptop or desktop computer: (1) an ISP, (2) a ROUTER and (3) a Web browser.

49. The basic building blocks of the Internet that allow the network communication and its successful implementation consist of: An Internet backbone is a collection of routers connected by high-speed point-to-point networks. A NAP is a router that connects multiple backbones. Regional networks are smaller backbones that cover smaller geographical areas (e.g., cities or states). A point of presence (POP) is a machine that is connected to the Internet. ISPs provide dial-up or direct access to POPs. Commercial organization with permanent connection to the Internet that sells temporary connections to subscribers. The computer first connects to the ISP and then to the Internet.

50. Internet Configuration: Internet service provider (ISP) offers Internet accounts to configure the network connections either by using a dial-up access, high-speed access, or wireless access. Dial-up access: Dial-Up Connection works over an ordinary phone line, using analog modems establishing the Point-to-Point Protocol (PPP). High-speed access: A high-speed connection also known as the broadband connection comprises of divergent options such as Digital Subscriber Line (DSL), Integrated Services Digital Network (ISDN) Lines, leased line, and cable Internet connections. DSL is a family of all-digital, high-speed lines that use normal phone wires with special modems. ISDN lines, like DSL lines, are all-digital, high-speed phone lines that provide a faster way to connect to the Internet.

51. To connect your computer to an ISDN line, you need an ISDN adapter. More recently, major ISPs and online services, like EarthLink and AOL, had made deals with cable TV companies to provide cable Internet access. The cable modem allows the same network that brings you variety of TV channels get millions of websites. Finally, Digital Satellite Systems (DSS), or direct broadcast satellite is a method by which Internet content is downloaded to a satellite dish and then transmitted directly from the dish to the user’s PC. Wireless access: Another way to connect to the Internet is via a Wireless access using Wi-Fi technology.

52. https://youtu.be/93-3zmVvCGU Web Browser: A web browser is a software program that retrieves, presents, and traverses information resources on the Web. The primary function of a browser is to identify the URL and bring the information resource to user. To identify a web pages’ exact location, a web browser relies on a URL. Some of the well-known web browsers are Internet Explorer, Netscape Navigator, Mozilla Firefox, Opera, Google Chrome, Safari, and so on.

53. Internet Organizations: The Internet is more of a concept than an actual tangible entity, and it relies on a physical infrastructure that connects networks to other networks. Internet Society (ISOC): ISOC is concerned with the long-term coordination of the Internet development. Internet Engineering Task Force (IETF): IETF is an open international community of network professionals and experts. Internet Corporation for Assigned Names and Numbers (ICANN): ICANN is an internationally organized non-profit organization under Californian rights.

54. The responsibilities of ICANN are IP address space allocation, gTLD (generic Top-Level Domain) and ccTLD (country code TLD), DNS management (ICANN is the body that decides about the introduction of new TLDs), Root server system management, and Protocol identifier assignment. Internet Assigned Numbers Authority (IANA): IANA is the predecessor organization of ICANN. It manages the different duties of ICANN. Internet Architecture Board (IAB): The IAB is responsible for the Internet architecture, as a whole, and protocol development oversight with respect to aspects like scalability, openness of standards and evolution of the Internet architecture. Internet Engineering Steering Group (IESG): IESG carries out the technical management of IETF activities and the Internet standards process.

55. Internet Research Task Force (IRTF): IRTF conducts research on protocols, applications, architecture, and technology. Internet Research Steering Group (IRSG): The IRSG is responsible for steering the IRTF and provides good conditions for research carried out by IRTF. World Wide Web Consortium (W3C): W3C develops web technology standards. Regional Internet Registries (RIR): RIRs are responsible for the management and allocation of Internet number resources: IP addresses and AS numbers.

56. Cyber Ethics : Cyber Ethics refers to the code of responsible behavior on the Internet. Cyber Ethics is the study of ethics pertaining to computers, covering user behaviour and what computers are programmed to do, and how this affects individuals and society’s. And increase of young children using the internet, it is now very essential than over to tell children about how to properly operate the internet and its dangers. Computer ethics was first coined by Walter Maner a professor at blowing Green state University.

57. Importance of Cyber Ethics: To protect personal and commercial information such as login & password info, Credit card and account information, and Government and commercial Databases. It also controls Unwanted internet mail and ADS(Spam) To Control Plagiarism, Student identity fraud, and the use of copyrighted material etc… To Make ICT Available and Accessible to all peoples , Including Disabled and deprived. To promote moral and Social Values in society. Ex: Internet Hacking Hacking is done by stealing classified information, stealing passwords to get into a site and also recasting a website without permission.

58. Provisions / tenets of Cyber Ethics: Your Computer should not used to harm others. Your Cyber Knowledge should not be used to steal other peoples resources. One Should not use or copy software's for which you have not paid. You should not break into Someone Else’s Accounts. Never use other peoples resources with out their consent. Communicating , sharing, and contributing to E-Society in a positive manner. To prevent cyber crimes Government has taken positive role in making resources for parents and children's to learn about cyber Ethics.

59. ISO (International Organization for Standardization) is an independent, non-governmental organization that develops standards to ensure the quality, safety and efficiency of products, services and systems. The Internet Engineering Task Force (IETF) is the body that defines standard operating internet  protocols  such as  TCP/IP . ICANN (Internet Corporation for Assigned Names and Numbers) is the private, non-government, nonprofit corporation with responsibility for Internet Protocol (IP) address space allocation, protocol parameter assignment, domain name system (DNS) management and root server system management functions.

60. The Internet Assigned Numbers Authority (IANA) is a standards organization that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System (DNS), media types, and other Internet Protocol–related symbols and Internet numbers. The Interactive Advertising Bureau (IAB) is an American advertising business organization that develops industry standards, conducts research, and provides legal support for the online advertising industry. What is the role of the IAB? The Role of the IAB: The IAB serves to provide Architectural Oversight for Internet procedures, and to provide oversight in the process of creating Internet standards, including appeals.

61. IESG is an acronym for the Internet Engineering Steering Group. This group is assigned with the responsibility of technical management of the Internet Engineering Task Force (IETF), which concentrates on producing high-quality and relevant technical documents for the betterment of the internet. The Internet Research Task Force (IRTF) focuses on longer term research issues related to the Internet while the parallel organization, the Internet Engineering Task Force ( IETF ), focuses on the shorter term issues of engineering and standards making. The IRTF is comprised of a number of focused and long-term Research Groups. These groups work on topics related to Internet protocols, applications, architecture and technology.

62. Internet Research Steering Group. The Internet Research Steering Group forms part of the IRTF (Internet Research Task Force) and is responsible for setting the priorities and coordinating research activities of the IRTF. The Internet Research Task Force (IRTF) promotes research of importance to the evolution of the Internet by creating focused, long-term Research Groups working on topics related to Internet protocols, applications, architecture and technology. The World Wide Web Consortium (W3C) is an international community that works together for the long-term growth of the Web. What is the role of RIR? RIRs allocate and register blocks of Internet number resources (IPv4, IPv6 and ASNs) and provide related services to Internet service providers (ISPs) and other organizations in their geographical service regions.