1. Networks QUME 185 Introduction to Computer Applications

2. 2 Fundamental Concepts Network: two or more computers, or other devices, connected together. Connections: cables, wireless or other means. Network communications follow rules: protocols

3. 3 Networks: large and small LAN, WAN, Internet, Intranet LAN – Local Area Network WAN – Wide Area Network Internet (public) Intranet (private)

4. 4 Benefits of LANs and WANs Increased efficiency and lowered costs sharing equipment (printers etc) sharing of files and documents (group work) sending messages (e-mail, conferencing) sharing databases (access to customer lists, price and inventory information) administering shared software

5. 5 Client/Server model Most networks rely on the client/server model the client is the requesting program or user (usually a personal computer) the server is the computer that: manages network resources receives the request from client delivers the requested file (or other service) to the client

6. 6 Servers Servers can have many roles, and often serve multiple roles. They can be one or any of the following: File Server Print Server Database Server Web Server

7. 7 The Internet The Internet is a group of networks linked together with routers in a way that allows any computer on any network to be able to communicate with another computer on any other network.

8. 8 The Internet Corporate LANs and WANs also connect to the Internet

9. 9 Components & Protocols Network Components: Transmit and receive data Conform to a common set of rules that enable them to communicate with each other. These rules are called protocols Network Protocols check to see if a connection is free to send data, and ensure that data do not collide on the network

10. 10 TCP/IP These two protocols form the basis of Internet technology Powerful and flexible Used on the Internet to enable data to be sent from one computer to another across multiple networks

11. 11 IP – Internet Protocol Each computer, or other device, attached to the Internet has an IP address that uniquely identifies it from the millions of other computers on the Internet Typical format: 142.25.103.249 (This is the IP address for viu.ca)

12. 12 TCP – Transmission Control Protocol Divides large data files into packets Each packet is transmitted separately Packets are reassembled at the destination so that they are understandable as an e-mail message, Web page or other file type Process is controlled by TCP

13. 13 Transmission process Data packets are forwarded from one network gateway to another across the Internet The packets don’t necessarily all take the same route Therefore, may not arrive at their destination in the same order they were sent

14. 14 Keeping Track of Packets Each packet carries: IP address of sender IP address of destination Where it belongs in the larger file

15. 15 Summary of TCP/IP Simply stated, TCP/IP allows for the "handshake" that introduces distant and different computers to each other.... TCP controls and keeps track of the flow of data packets, IP addresses and forwards individual packets. TCP/IP, which became the required protocol of ARPANET in 1983, also allowed ARPANET to expand into the Internet, facilitating features like remote login via Telnet --- and, later, the World Wide Web. FROM: http://web.mit.edu/invent/iow/cerf.html Vinton Cerf – Developed TCP/IP http://www.ibiblio.org/pioneers/

16. 16 The World Wide Web Just one application of the Internet Web pages are stored on servers throughout the world The application software used to access web pages is called a Browser (such as Firefox, Safari, Internet Explorer and Opera) Web browser = Web client

17. 17 Some Web Acronyms HTTP – Hypertext Transfer Protocol URL – Uniform Resource Locator – the unique address of the web page http://www.viu.ca/index.asp protocol | domain name | web page

18. 18 Corporate Intranets / Extranets Organizations use TCP/IP networking protocols and web technology to create private, corporate networks Intranets – for use within the organization itself: InVIU for example Extranets – for use by the organization and, for example, its suppliers or customers These networks use the same network infrastructure (hardware) as the LAN or WAN, but send the data using internet protocols.

19. 19 Networking – just the basics Networking is a very complex topic This was a very simple overview Best to refer to networking specialists

20. 20 Class discussion exercise What do you think are the basic computer skills that a person needs for 2012 and beyond?

21. 21

22. How a web server works on the Internet