Transcript Document
INF550/NZDB550 Networking Client/Server Links 2 or more computers together Servers provide computing services to user PCs User PCs may be thin or thick clients Eg server may be a web server providing web resources to the client (user) Peer-to-Peer Network 2 computers are linked so they can access all of the files on the other computer Type of Client/Server Accessing unused processing power Eg SETI@home File sharing Eg BitTorrent Terminal Server Network Processing power in one centralised computer Often the terminals are thin clients (dumb terminals) Remote Desktop Services Used by cloud services where the terminal server hosted on the Internet The Internet Global WAN Coming back to this later Intranets Private networks within an organisation Similar to the Internet but only for Employees to use Generally contains Policies and procedures Useful information for the employee (eg payroll functions, news etc) Communication Collaboration Useful for Larger organisations Geographically separated organisations Extranets Connects parts of the intranets of different organisations Allows business partners to communicate securely over the Internet using virtual private networks What is a Protocol? An agreed upon format for transmitting data between two devices Lots and lots of different protocols Some Important Protocols TCP – Transmission Control Protocol Breaks down data into packets in preparation of sending the data IP – Internet Protocol Communicates between computers by sending and receiving the data over the Internet Related to the Web HTTP – Hyper Text Transfer Protocol Sends request from a browser on the client to the web sever Returns the web content (web pages) from the server back to the client HTTPS – Secure HTTP Allows for secure communications FTP – File Transfer Protocol Allows transmission of files between computers Related to Email SMTP – Simple Mail Transfer Protocol Transmits e-mail IMAP – Internet Message Access Protocol Stores and retrieves e-mails POP – Post Office Protocol Downloads e-mails from an e-mail server to a computer Sending Messages A message is broken into smaller packets Packets are sent over the network The message is reassembled at the receiving end VOIP systems use ‘jitter buffers’ which stack packets and drop late ones. Packet sending activity 1969 - ARPAnet Advanced Research Project Agency of the US Department of Defence Purpose was to test the feasibility of a WAN over which researchers, educators, military personnel and government agencies could Share data Exchange messages Transfer files The Internet What is The Internet? Global WAN Network of networks Connecting approximately 1 million organisational computer networks The transport mechanism In more than 200 countries On all continents (including Antarctica) Playing a role in the daily routines of almost 2 billion people Access data Communicate, collaborate and exchange information Seamlessly around the world quickly and inexpensively The World Wide Web Introduced 1991/1992 Inventor - Tim Berners-Lee Based on Hyperlinks Idea was to build a web of hypertext documents to be viewed on browsers using a client-server architecture Based on universally accepted standards for storing, retrieving, formatting and displaying information The World Wide Web is part of the Internet, not The Internet Some Interesting Statistics World Wide Web Timeline A Day in the Life of the Internet 1 A Day in the Life of the Internet 2 Browsers Used to surf the Internet Uses a browser What do you think the most popular browsers are? Browser Statistics Uses an address to locate the resources required URL – Universal Resource Locator URLs Uniform Resource Locators All URLs have at least two parts Protocol Domain name Top-level domains (TLDs) provide further information about the website List of Country TLDs All about web-servers Internet Infrastructure Finding Things on The Internet Parts of the URL NZ Second Level Domain Names eCommerce Buying, selling, transferring or exchanging Products, services or information Via computer networks eBusiness Buying and selling goods and services Servicing customers Collaborating with business partners Performing electronic transactions within an organisation Types Business-to-Consumer (B2C) Organisations selling to individual buyers Business-to-Business (B2B) Buyers and sellers are both business organisations Consumer-2-Consumer (C2C) Individuals selling to other individuals Eg auctions eGovernment Delivery of information and public services to citizens, business partners and suppliers Business-to-Consumer Electronic storefronts Website representing a single store Electronic malls or cybermall Collection of individual shops Electronic banking Online Job Market Travel services Online advertising Business-to-Business Ability to form electronic relationships with Distributors Resellers Suppliers Customers Other partners eGovernment in NZ Government ICT Strategy and Action Plan to 2017 System Shifts needed igovt identity verification service RealMe Cloud Computing Connects through a network – usually the Internet Has a front end The user sees Includes the client computer Includes the application required to access the cloud computing system Has a back end Does all the work In the ‘cloud’ Includes computers, servers and data storage systems Advantage Dramatically lowers cost of infrastructure Disadvantages Privacy Security Reliability Think Dot Com and Megauploads Types A list of many different types Instant Messaging Reuniting and Friends Facebook Linkedin Blogs Sandra’s Blog Microblogs Twitter Wikis Wikipedia Personal websites Sandra’s Tutorials Others Flickr You Tube RSS Feed Questions How does NMIT use Social Media Explore these to see how they use them How useful is Wikipedia ? How reliable is Wikipedia? Should Wikipedia be used for assignment work? Post answers to discussion forum in the current week on the course page Other Useful Tools for Study Diigo Bookmarking useful websites and electronic articles Zotero Online referencing software If you thought Word referencing was good, try this to blow your mind!