Chapter 5 Networks Communicating and Sharing Resources

1. Chapter 5 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 to allowcommunication and collaboration between users. • A group of two or more computer systems linked together to exchange data. • Any device connect to the network referred to as a node. • Any device has a unique logical address (name). • Any device also has a unique physical address (MAC). • A node need NIC to connect to network.

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. 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

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

7. Advantages and Disadvantages of Networking: • Advantages: • Reduce hardware costs. • Sharing application. • Sharing information resources. • Centralized data management. • Connecting people. • Disadvantages: • Loss of autonomy. • Lack of privacy. • Security Threats. • Loss of productivity.

8. Common Network Types • Local Area Network (LAN) LAN interconnects devices in a limited area such as a home, school, or office building using network media. • Contains printers, servers and computers. • Systems are close to each other. • Organizations often have several LANS. • LANs Types • Wired LAN • Wireless LAN • VLAN • LAN Protocol: Standard or Rules specify how two dissimilar network components can establish a communication.

9. Wired LAN • Network Cables • Unshielded Twisted Pair (UTP) Cable • Shielded Twisted Pair (STP) Cable • Coaxial Cable • Fiber Optic Cable • Ethernet: the most popular cabling technology in LAN. • Ethernet uses a protocol called CSMA/CD

10. Network Interface Card • Connects node to the media • Unique Machine Access Code (MAC)

11. Wireless LANs Wi-Fi:wireless LAN standard that offers Ethernet speeds through the use of radio waves instead of wires. • Wifistandards and speeds

12. Network layers

13. Types Of (LAN)Structure

14. 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

15. 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 private network over the internet

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

17. 1- Bus 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 onenode can transmit at a time. • Slow & Easy to crash • Used at home or small office.

19. 2- Star 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. 3- Ring 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. 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

24. WAN PROTOCOLS • TCP/IP are open protocols that define how the Internet works. • IPdefines the internet addressing scheme. • TCP defines how one computer can contact another to exchange control and confirmation messages. • Circuit switching A protocol (method) used in a telephone systems with direct connection between the communicating devices. • Packet switching A method used when no effort is made to create a single direct connection between the communicating devices.

25. Network Hardware

26. Network Hardware