Chapter 6: Networks

1. Chapter 6: Networks Communicating and Sharing Resources

2. Chapter objectives: • Understand basic networking. • Discuss the advantages and disadvantages of networks. • Distinguish between Peer-to-Peer & client/server LAN. • Define topology and understand how 3 LAN topologies differ. • Explain the importance of protocols. • Most widely used protocol & it’s versions. • Identify the special components of wide area network (WAN) that differentiate from LAN.

3. Network Definition • Set of technologies that connects computers • Allows communication and collaboration between users

4. The Uses of a Network • Simultaneous access to data • Data files are shared • Shared files stored on a server • Software can be shared • Shared peripheral device • Printers and faxes are common shares • Reduces the cost per user • Devices can be connected to the network

5. Sharing Data File server contains documents used by other computers.

6. The Uses of a Network • Personal communication • Email • Conferencing • Voice over IP • Phone communication over network wires • Easier data backup • Backup copies data to removable media • Server data backed up in one step

7. Voice Over IP

8. Advantages and Disadvantages of Networking: • Advantages: • Reduce hardware coasts. • Application sharing. • Sharing information resources. • Centralized data management. • Connecting people. • Disadvantages: • Loss of autonomy. • Lack of privacy. • Security Threats. • Loss of productivity.

9. Common Network Types • Local Area Network (LAN) • Contains printers, servers and computers • Systems are close to each other • Contained in one office or building • Organizations often have several LANS

10. Common Network Types • Wide Area Networks (WAN) • Two or more LANs connected • Over a large geographic area • Typically use public or leased lines • Phone lines • Satellite • The Internet is a WAN

11. Hybrid Network Types • Home Area Network (HAN) • Small scale network • Connects computers and entertainment appliances • Found mainly in the home

12. Hybrid Network Types • Personal Area Network (PAN) • Very small scale network • Range is less than 2 meters • Cell phones, PDAs, MP3 players

13. Types Of (LAN)Structure

14. Wired VS Wireless LAN • Wired LAN : • Wire Based • Twisted-pair cabling • Coaxial cable • Fiber-optic cable • Wireless LAN. • radio waves • encryption software

15. Peer-to-Peer Network(P2P): • Tend to slow down as the number of users increase. • Keeping track of all the shared folders & files can be confusing. • Security not strong because the lack of hierarchy. • Nodes access resources on other nodes • Each node controls its own resources

16. Client/Server network • Nodes and servers share data roles • Nodes are called clients • Servers are used to control access • Database software • Access to data controlled by server • Server is the most important computer Virtual Private Network (VPN) operates a a private network over the internet

17. LAN Topologies • Network Topology: the physical layout of the LAN. • Bus Topology. • Star Topology. • Ring Topology.

18. 1- Bus Topology • One wire or cable connects all nodes. • Terminator special connectors ends the circuit. • Advantages • Simple, reliable and easy to expand • Easy to setup • Small amount of wire • Disadvantages: • Only one node can transmit at a time. • Contention. • Slow & Easy to crash • Used at home or small office.

19. 1- Bus Topology

20. 2- Star Topology • Solves the expansion problems of the bus topology. • All nodes connect to a hub • Packets sent to hub • Hub sends packet to destination • Advantages • Easy to setup and add users. • One cable can not crash network • Disadvantages • Loss of hub crash down the entire network • Uses lots of cable • Most common topology used at office buildings, computer labs and WAN.

21. 2- Star Topology

22. 3- Ring Topology • Nodes connected in a circle. • Not in common used today. • Special unit of data called Token travels around the ring and is used to transmit data • Nodes can transmit only when it posses the token. • Advantages • Time to send data is known • No data collisions • Disadvantages • Slow • Lots of cable • Well suited for use within a division of a company or on one floor of a multi floor building.

23. 3- Ring Topology

24. LAN Protocols • Protocol: (Standard or Rules) fixed formalized exchanges that specify how two dissimilar network components can establish a communication. • 1. Ethernet: the most popular cabling technology in LAN. • 2. Wi-Fi: wireless LAN standard that offers Ethernet speeds through the use of radio waves instead of wires. LAN Technologies

25. Network Hardware • Network interface cards • Network adapter • Connects node to the media • Unique Machine Access Code (MAC)

26. Network Hardware • Hubs • Center of a star network • All nodes receive transmitted packets • Slow and insecure

27. Network Hardware • Switches • Replacement for hubs • Only intended node receives transmission • Fast and secure

28. Network Hardware • Bridge • Connects two or more LANs together • Packets sent to remote LAN cross • Other packets do not cross • Segments the network on MAC addresses

29. Network Hardware • Router • Connects two or more LANs together • Packets sent to remote LAN cross • Network is segmented by IP address • Connect internal networks to the Internet • Need configured before installation

30. Network Hardware • Gateway • Connects two dissimilar networks • Connects coax to twisted pair • Most gateways contained in other devices

31. Wide Area Networks • The special components of WANs that differentiate them from LANs: • A point of presence POP • backbones

32. WAN PROTOCOLS • TCP/IP are open protocols that define how the Internet works. • IP is the most fundamental of all internet protocol • Circuit and packet switching

33. WAN APPLCATION • LAN-TO-LAN Connections • Transaction Acquisition