1. 2.2 Interfacing Computers MR JOSEPH TAN CHOO KEE TUESDAY 1330 TO 1530 http://computing2013.wiki.hci.edu.sg/

2. 2.2.1 Local Area Network (LAN), Wide Area Network (WAN) and examples of current technologies 2.2.2 the different purposes of the hardware for a network such as servers, clients, switches, routers and bridges 2.2.3 Why organizations use intranets 2.2.4 concept of cloud computing and kinds of cloud (i.e. application, infrastructure, and platform) 2.2.5 rate of data transmission (in baud or bps) 2.2.6 synchronous and asynchronous data transmission 2.2.7 simplex, half duplex and full-duplex mode of transmission 2.2.8 Packet switching and circuit switching for data transmission 2.2.9 the use of parity checks and check sums in detecting and correcting errors in data transmission 2.2 Interfacing Computers Students should know and understand

3. 3.3.1 Methods and tools for creating a network application(eg. Client Server scripting/programming, hand-held devices, technology standards and application software). 3.3.2 methods for ensuring security of a network application (eg. Access rights and password access) 3.3.3 network security for network applications (eg. firewalls) 3.3.4 copyright, ethics and social issues involving network applications 3.3 Network applications Students should know and understand

4. What is a Network? What is the purpose of setting up a Network eg. Home, School? What are the benefits of setting up a Network? What are the common draw backs of setting up a Network? Comments on wiki http://computing2013.wiki.hci.edu.sg/ (10 Mins)

5. What is a Network?

6. Networking is the practice of linking two or more computing devices together for the purpose of sharing resources. Networks are built with a mix of computer hardware and computer software.

7. Show an awareness of the hardware and software for a network What is the purpose of setting up a Network? Linked up multiple devices eg. >1 PCs, notebooks, HP, Tablets etc Purpose of linking up: To share resources To share printing devices To share storage space To share bandwidth To share software Easy maintenance of machines

8. Show an awareness of the hardware and software for a network What are the benefits of setting up a Network? Allowed the sharing of resources No duplication needed eg. Printer, storage, bandwidth Convenience Easy access to resources, allowed remote access Easy access to information Efficient management of multiple machines Reduce cost of maintenance/operations (manpower, time & $)

9. What are the draw backs of setting up a Network? Cost (Hardware, bandwidth) Expertise (Set-up, maintain) Security (Control access)

10. Rank(High, Average, Low) the level importance of each of these possible drawbacks in the 3 different settings. SettingsCostExpertiseSecurity Personal(Hm)LowLowLow SchoolsAverageAverageAverage MilitaryHighHighHigh

11. LAN Vs WAN Internet Is not the only Network

12. Describe the characteristics of a local area network(LAN) and wide area network(WAN) Networks Classifications Local Area Network (LAN) Wide Area Network (WAN)

13. Describe the characteristics of a local area network(LAN) and wide area network(WAN) Networks Classifications Local Area Network (LAN) Is a network that connects computers & devices in a limited geographical area such as home, school labs etc What is WLAN?

14. Wireless Local Area Network A LAN that doesn’t rely on wired connections Common technology WIFI, Bluetooth WLAN What are the advantages of WLAN?

15. Describe the characteristics of a local area network(LAN) and wide area network(WAN) Networks classifications Wide Area Network (WAN) Is a network that covers a large geographical area(city, country or the world) using a communications channel that combines many types of media such as telephone lines, cables and radio waves. WAN Can be one large network Consist of 2 or more LANs connected together Internet is the world’s largest WAN

16. What distinguish one type of Network from another?

17. Purpose of the set up Area of coverage (within a lab to the rest of the world) Connecting devices differs Transmission media differs Cost/Security ….. Distinguishing factor

18. LANWAN Intranet Internet Networks

19. What is an Intranet?

20. Network Architectures The design of computers, devices and media in a network.

21. 2 different ways of Communicating

22. Network Architectures Client- Server The type of computing system in which one powerful workstation serves the requests of other systems Characteristics One or more computers acts as server Other computers request service from server

23. Network Architectures Client- Server Purpose of Server A computer server is the computer which provide services to other systems Control access to hardware, software and other resources on the network Centralized storage area for programs, data Purpose: Filtering of network traffic Servers are often dedicated, meaning that they perform no other tasks besides their server tasks Clients Clients are the individual components which are connected in a network. Client sends a request/query to server and server responds accordingly. The client doesn't share any of its resources. They are subordinates to servers, and their access rights are defined by servers only

24. Components of Client-Server Network 1) Clients 2) Servers 3) Network Devices :- They connect the clients and servers, and at the same time ensure proper collision free routing of information. 4) Other components like scanner, printer, etc can also be connected to network architecture.

25. What are the different types of servers? *Servers has dedicated roles. Group work time: Identify the different types of servers What is their primary role in a network? Instructions: Work in groups/Label each page with your names 15 mins Selected groups to present Update your work on: http://computing2013.wiki.hci.edu.sg/

26. File server is a computer and storage device dedicated to storing files Any user on the network can store files onto the server Print server is a computer that manages one or more printers Mail Servers An e-mail server is a computer within your network that works as your virtual post office. It handles the transfer of messages to and from other mail servers and email clients. Proxy Servers sit between a client program typically a Web browser and an external server (typically another server on the Web) to filter requests, improve performance, and share connections. Domain Name Servers Domain Name systems: Allows Clients to query for IP addresses(32 bit) of hostnames.

27. Peer-to-Peer Each computer, called a peer, has equal responsibilities and capabilities. They are able to share resources without going through a server computer. In P2P networking the need for central servers is eliminated, and all computers interact and share resources as equals.

28. Peer-to-Peer Each computer, called a peer, has equal responsibilities and capabilities. They are able to share resources without going through a server computer.

29. Peer-to-Peer Each computer, called a peer, has equal responsibilities and capabilities. They are able to share resources without going through a server computer. In P2P networking the need for central servers is eliminated, and all computers interact and share resources as equals. What are the advantages? What are some of the issues?

30. Peer-to-Peer Advantages: No need for a centralized server $ No specialist staff to maintain the server More resilient in case of failures and traffic bottlenecks If one computer fails it will not disrupt any other part of the network. More resources are available

31. Peer-to-Peer What are some of the issues? User computer can be slow down because it is access by others Little or no Security Virus(Responsibility of each user) Illegal access to computer by others (eg.Hacking) No control over what get shared Copyrights (You do not have the right to the file)

32. Napster Case Study http://www.youtube.com/watch?v=CSpzW8bkkPc

33. What are the benefits and drawbacks of a client-server network?