Networking topics like ISP,DNS etc


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Networking topics like ISP,DNS etc

  1. 1. Dynamic Host Configuration Protocol (DHCP)• When dealing with IP addressing, it can be very management intensive to manually assign IP addresses and subnet masks to every computer on the network.• The Dynamic Host Configuration Protocol (DHCP) enables automatic assignment of IP addresses.• This is usually performed by one or more computers (DHCP Servers) that assigns IP addresses and subnet masks, along with other configuration information, to a computer as it initializes on the network. 1
  2. 2. Domain Name System (DNS)• The Domain Name System (DNS) protocol provides host name and IP address resolution as a service to client applications.• DNS servers enable humans to use logical node names, utilizing a fully qualified domain name structure, to access network resources.• Host names can be up to 260 characters long 2
  3. 3. File Transfer Protocol (FTP)• The File Transfer Protocol (FTP) is a protocol for sharing files between networked hosts.• FTP enables users to log on to remote hosts.• Logged-on users can inspect directories, manipulate files, execute commands, and perform other commands on the host.• FTP also has the capability of transferring files between dissimilar hosts by supporting a file request structure that is independent of specific operating systems. 3
  4. 4. Simple Mail Transfer Protocol (SMTP)• The Simple Mail Transfer Protocol (SMTP) is a protocol for routing mail through internetworks.• SMTP uses the TCP and IP protocols.• SMTP doesn’t provide a mail interface for the user.• Creation, arrangement, and delivery of messages to end users must be performed by an email application. 4
  5. 5. HTML Audio Using Plug-ins• A plug-in is a small computer program that extends the standard functionality of the browser.• Plug-ins can be added to HTML pages using the <object> tag or the <embed> tag.• Using The <embed> Element<embed height="100" width="100" src=“song.mp3">• Using The <object> Element<object height="100" width="100" data=“song.mp3"></object> 5
  6. 6. Very Small Aperture Terminal (VSAT)• What does Very Small Aperture Terminal (VSAT) mean?• A very small aperture terminal (VSAT) is a small telecommunication earth station that receives and transmits real-time data via satellite.• A VSAT transmits narrow and broadband signals to orbital satellites. The data from the satellites is then transmitted to different hubs in other locations around the globe. 6
  7. 7. • It is used for the reliable transmission of data, video, or voice via satellite.• It requires no staff or additional technology to operate it.• It simply plugs into existing terminal equipment.• A VSAT consists of two parts, a transceiver that is placed outdoors in direct line of sight to the satellite and a device that is placed indoors to interface the transceiver with the end users communications device, such as a PC . 7
  8. 8. • VSAT end users have a box that acts as an interface between the computer and the external antenna or satellite dish transceiver.• The satellite transceiver sends data to and receives data from the geostationary satellite in orbit.• The satellite sends and receives signals from an earth station, which acts as the hub for the system.• Each end user is connected to this hub station through the satellite in a star topology.• For one VSAT user to communicate with another, the data has to be sent to the satellite.• Then the satellite sends the data to the hub station for further processing. The data is then retransmitted to the other user via a satellite. 8
  9. 9. • The majority of VSAT antennas range from 30 inches to 48 inches.• Data rates typically range from 56 Kbps up to 4 Mbps.VSATs are most commonly used to transmit:• Narrowband data: This includes point of sale transactions such as credit card, polling or radio- frequency identification (RFID) data, or supervisory control and data acquisition (SCADA) data• Broadband data: For the provision of satellite Internet access to remote locations, Voice over Internet Protocol (VoIP) or video 9
  10. 10. Configurations of VSAT• A star topology, using a central uplink site, such as a network operations center (NOC), to transport data back and forth to each VSAT terminal via satellite.• A mesh topology, where each VSAT terminal relays data via satellite to another terminal by acting as a hub, minimizing the need for a centralized uplink site.• A combination of both star and mesh topologies. 10
  11. 11. Working of HUB station• Each end user is interconnected with the hub station via the satellite, forming a star topology.• The hub controls the entire operation of the network .• For one end user to communicate with another, each transmission has to first go to the hub station that then retransmits it via the satellite to the other end users VSAT. 11
  12. 12. VSAT customers• Supermarket Shops.• Chemist Shops.• Garages / vehicle sales / petrol stations / motor spares.• Hotel chains.• Insurance offices.• Car rental offices.• Airlines, travel agents.• Financial institutions - ATM machines.• Manufacturers - sales offices, service divisions, plants.• Job centers.• Customs and tax offices / border passport control checkpoints.• Data file and software distributors.• Pipeline monitoring, oil rigs.• Rural telephony, data, videophone.• Schools, news channel Vans.• Environmental monitoring. 12
  13. 13. Advantages of VSAT• Reliable Communications• Remote Communications• Efficient Network Management• Less Deployment time• Less Maintenance• Less Setup Cost• Expansion Flexibility 13
  14. 14. Uniform Resource Locator(URL)• Definition: URL stands for Uniform Resource Locator. A URL is a formatted text string used by Web browsers, email clients and other software to identify a network resource on the Internet.• Network resources are files that can be plain Web pages, other text documents, graphics, or programs.• URL strings consist of three parts : 1. network protocol 2. host name or address 3. file or resource location• These substrings are separated by special characters as follows: protocol :// host / location 14
  15. 15. • URL Protocol: The protocol substring defines a network protocol to be used to access a resource. Typical URL protocols include http://,https://, ftp://, and mailto://• URL Host: The host substring identifies a computer or other network device.,, are various hosts.• URL Location: The location substring contains a path to one specific network resource on the host. Resources are normally located in a host directory or folder. Eg.: or 15
  16. 16. WEB PORTAL• A web portal is a term, often used interchangeably with gateway, for a World Wide Web site whose purpose is to be a major starting point for users when they connect to the Web.• Apart from the standard search engines feature, web portals offer other services such as e-mail, news, stock prices, information, databases and entertainment.• Some major general portals include Yahoo, CNET, AOL, and MSN. 16
  17. 17. • Typical services offered by public portal sites include a directory of Web sites, a facility to search for other sites, news, weather information, e-mail, stock quotes, phone and map information, and sometimes a community forum.• Private portals often include access to payroll information, internal phone directories, company news, and employee documentation. 17
  18. 18. • Web portals are sometimes classified as horizontal or vertical.• A horizontal portal is used as a platform to several companies in the same economic sector or to the same type of manufacturers or distributors.• A vertical portal is a specialized entry point to a specific market or industry niche, subject area, or interest. 18
  19. 19. Types of web portals• Personal portals• News portals• Government web portals• Cultural Portals• Corporate web portals• Stock portals• Search portals• Tenders portals• Hosted web portals• Domain-specific portals 19
  20. 20. Portal vs WebSite• A portal is generally a vehicle by which to gain access to a multitude of services.• A web site is a destination in itself.• As such the term website refers to a location on the Internet (see this) that is unique and can be accessed through a URL (see this).• By that definition a web portal is in fact also a website.• However there is a distinction between the two terms based on the subject and content of the website.• A website is also a web portal if It transmits information from several independent sources that can be, but not necessarily are, connected in subject; thus offering a public service function for the visitor which is not restricted to presenting the view(s) of one author. 20
  21. 21. • The Portal and website can be differentiated as : Authentication: Portal: It provides facility of Logging-In. Provides you with information based on who you are. e.g.,, Website: No log-in. e.g. Personalization: Portal: Limited, focused content. Eliminates the need to visit many different sites. e.g. You type in your user name and password and see your yahoo mail only. Website: Extensive, unfocused content written to accommodate anonymous users needs. Customization : Portal: You will select and organize the materials you want to access. Organized with the materials you want to access. Website: Searchable, but not customizable. All content is there for every visitor. e.g. you can navigate to yahoo mail, yahoo shopping, geo cities, yahoo group. If you wish to use any of these services you will either have to authenticate yourself and see things personalized to you or you can simply visit sections that are for everyone like yahoo news were if you are not signed in then the default sign in is 21 guest.
  22. 22. Internet Service Provider (ISP)• Definition - What does Internet Service Provider (ISP) mean?• An Internet service provider (ISP) is a company that provides customers with Internet access.• Data may be transmitted using several technologies, including dial-up, DSL, cable modem, wireless or dedicated high-speed interconnects.• ISP provides a software package username , password and access phone number 22
  23. 23. Classification of ISP1.Access providers2.Mailbox Providers3.Hosting ISPs4.Transit ISPs5.Virtual ISPs6.Free ISPs 23
  24. 24. WWW• Definition: The term WWW refers to the World Wide Web or simply the Web. The World Wide Web consists of all the public Web sites connected to the Internet worldwide, including the client devices that access Web content.• The WWW is just one of many applications of the Internet and computer networks.• The World Web is based on these technologies: – HTML - Hypertext Markup Language – HTTP - Hypertext Transfer Protocol – Web servers and Web browsers• Researcher Tim Berners-Lee led the development of the original World Wide Web in the late 1980s and early 1990s. 24
  25. 25. TELNET• The ability to log onto a network from a distant location. Generally, this implies a computer, a modem, and some remote access software to connect to the network. 25
  26. 26. Why we need FTP ?• Purpose: To Transfer files between two computers• Goals of FTP Service • Promote sharing of files (programs and/or data) • Encourage indirect/implicit use of remote computers • Shield users from variations in file storage among hosts • Transfer data reliably and efficiently 26
  27. 27. • At first, file transfer may seem simple• Heterogeneous systems use different: – Operating Systems – Character Sets – Naming Conventions – Directory Structures – File Structures and Formats• FTP need to address and resolve these problems 27
  28. 28. FTP Client Commands (issued by user interface)Command Descriptionget filename Retrieve file from servermget filename* Retrieve multiple files from server*put filename Copy local file to servermput filename* Copy multiple local files to server*open server Begin login to serverbye / close / exit Logoff serverls / dir List files in current remote dir on serverlcd Change local directorycd Change remote directoryrhelp / remotehelp Lists commands the server accepts * Sent to server as multiple command by User Protocol Interpreter
  29. 29. • There are two modes of transfer in FTP: ascii and binary.• Textual: ASCII is used only for files saved in ASCII format .• Binary is used for files that are formatted and saved using a wordprocessing software like WordPerfect (.txt), spreadsheets (.xls), images (.jpg, .gif), and many executable programs (.exe) and videos (.avi).
  30. 30. FTP Client• WS_FTP• FileZilla• FTP Voyager• WinSCP• FireFTP• SmartFTP• Microsoft Internet Explorer FTP Servers• WS_FTP Server• zFTPServer Suite• Golden FTP Server• FileZilla Server• Serv-U• Xlight• War FTP Daemon 30
  31. 31. E-Commerce• E-commerce is the buying and selling of products and services by businesses and consumers over the Internet.• E-commerce works as follows: 1. Consumers choose a product or service on a website 2. Consumers pay electronically on the website (online credit card transactions) or using a third party payment provider such as PayPal 3. The business owner or merchant receives the order and payment and the order is fulfilled (delivered by post, booked in for services etc) 31
  32. 32. Examples of Ecommerce• Online Shopping• Online Auctions• Electronic Payments• Online Ticketing• Internet Banking 32
  33. 33. Types of EcommerceEcommerce can be classified based on the type of participants in the transaction:• Business to Business (B2B) B2B ecommerce transactions are those where both the transacting parties are businesses, e.g., manufacturers, traders, retailers and the like.• Business to Consumer (B2C) When businesses sell electronically to end-consumers, it is called B2C ecommerce.• Consumer to Consumer (C2C) Some of the earliest transactions in the global economic system involved barter -- a type of C2C transaction. But C2C transactions were virtually non-existent in recent times until the advent of ecommerce. Auction sites are a good example of C2C ecommerce. 33
  34. 34. Advantages of E-Commerce• Quick, easy and convenient• Security Improvements• Convenient for Shoppers• Prices Often Lower• Product comparisons• Increased consumer reach• Shorter time frames 34