1. LANs and WANs Network size, vary from –simple office system (few PCs) to –complex global system(thousands PCs) Distinguish by the distances that the network cover

2. LANs Local Area Network (LAN) –network that connects computers located within a relatively limited area, under same management –has geographical limitation –For example : network within your house network within an office network within the school network within a cyber café ???

3. –Usually using LAN cables for connection –under the same administration and management –mainly resource sharing –with server PC client PC (workstation) peer PC (workstation) network connecting devices (e.g. hubs / switch)

4. Two major type of LANs –Peer-to-Peer network –Server-Client network Difference : –how data and information is stored

5. Server –Computers that provide shared resources to network users Client –Computers that access shared network resources provided by a server Media –the “wires “ that make physical connections Resources –any services and device made available for use by members of the network

6. How to decide to implement which network –Size of the organization –level of security required –type of business –level of administrative support available –amount of network traffic –needs of network users –network budget

7. Peer-to-Peer network No dedicated servers no hierarchy among the computers all the computers are equal --- peers each computer - client / server no administrative responsible for the entire network users of each PC determine what data and hardware is shared

9. Consideration Size workgroups –Also called workgroups –implied small group of people –typically 10 or fewer computers Cost –relatively simple –no need for a powerful central server –less expensive

10. Consideration (Cont’d) OS –does not require the same standard performance and level of security –can have many OS –no additional software is required Implementation –PC are located at users desk –users acts as their own administrator and plan their security –connection is simple and easily visible cabling

11. Consideration (Cont’d) 10 users or fewer users share resources (files and printers) security is not an issue will experience only limited growth with the foreseeable future

12. Server-Client Network Most networks have dedicated servers –one that functions only as a server and not client or workstation –optimized to service request from network clients –to ensure the security of files and directories Standard models for networking

14. Advantage of Server-based Network –Sharing Resources provide access to files and printers with good performance but also security sharing can be centrally administrated and controlled –Security primary reason for choosing a server-based approach administrator sets the policy

15. –Backup can be scheduled several times a day or once a week –depending on the administrator which in turns depends on the importance and value of the data can be scheduled to occur automatically –Redundancy data duplicated and kept online (RAID) if harms to primary data, backup copy can be used

16. –Number of users can support thousands of users with the use of current monitoring and network management utilities, management become easy –Hardware consideration Client PC hardware configuration can be lowered –no additional RAM, disk storage space –lower the cost for large scale network

17. WANs Wide Area Network (WAN) –spans a wide geographical area across cities, countries or even continents –can connect computers and other devices on opposite sides of the world –made up of a number of interconnected LANs –the ultimate WAN is the INTERNET

19. Consists of two or more LANs connected via a communication channel –telephone lines –leased line –microwave –satellites Internet = the world’s largest WAN –global network connecting millions of computers