Introduction to Networking Chapter 10

2. Introduction to Networking Chapter 10

3. Learn how to… • Define the term networking and list three critical components. • Describe the five basic topologies. • Define the seven layers of the OSI model and the protocols that use it. • Describe the differences among LAN, MAN, and WAN. • Describe the physical network components.

4. Understanding Networks

5. Networks • A networkis the connection of two or more digital devices for communicating, transferring, or obtaining data. • The act of communicating over a network is called networking.

6. Networking

7. Characteristics of a Network • All networks require: • A physical connection (or wireless connection). • A set of communication rules called protocols. • One or more network services that will receive the communication.

8. Mainframe/Terminal Model • The mainframe/terminal model • A mainframeis a centralized computer to which users connect to obtain network services. • The terminalis a device with a keyboard, which you use to type commands or enter data to communicate with the mainframe computer.

9. Client-Server Model • Client-serverrefers to the manner in which computers exchange information by sending it (as servers) and receiving it (as clients). • Computers can serve dual roles as both servers and clients.

10. Multi-Tier • Large organizations may subdivide complex applications into multiple stages called tiers. • Multi-tiercomputing typically includes three tiers consisting of the user interface tier, the business tier, and the database tier.

11. Peer-to-Peer Model • Peer-to-peer(P2P)is a network architecture in which each workstation has equal responsibilities.

12. Enterprise Model • Enterprise model refers to networking within large organizations that dedicate entire servers to handling important tasks. • Serving mail • Hosting databases • Managing security • Routing network traffic

13. Push-Pull Technology • The push-pull metaphor • Pull means that you ask for the information. • When you click a hyperlink. • Push means that the information is being provided to you. • When stock quotes are automatically updated on your desktop or when weather is automated updated on your desktop. • See www.weatherbug.com

14. Complex Network

15. Network Operating Systems • A network operating systemis the software that adds to a computer the functions required for connecting computers together for networking. • Microsoft Windows • UNIX and Linux • Mac OS • Novel NetWare

16. Microsoft Windows • Microsoft Windows is the most wide spread network operating system. • Every version of Windows contains networking capability, but some versions do not support all network services. • For a history of Windows server products, visit www.microsoft.com/windows/winhistoryserver.mspx

17. UNIX and Linux • The UNIXand Linuxoperating systems support the full range of networking services, including both client- and server-side components. • The Open Group holds the trademark and defines the official version of UNIX at www.unix-systems.org • Linux is an open source version of UNIX • To learn more, go to www.linux.org

18. Mac OS • The Macintosh OS Xoperating system has networking built in. • Behind the Macintosh user interface is a UNIX-based operating system. • To learn more, go to www.apple.com/macosx/features/unix

19. Novell NetWare • NetWareis a PC-based local area networking product that was one of the most dominant network operating systems during the decade following its invention in 1983. • However, when Microsoft marketed Windows NT in 1993, Novell NetWare’s market share dropped. • For more information, go to www.novell.com/products/netware

20. Classifying Network Topologies

21. Network Topologies • A network’s geographical shape is referred to as the network’s topology. • The five kinds of network topologies are: • Bus topology • Ring topology • Star topology • Hybrid topology • Mesh topology

22. Bus Topology • The bus topologyhas a single cable, called the busor the trunk, to which every device on the network connects. • All of the messages on the bus pass by each device, or node, on the bus. • It uses inexpensive coaxial cable that is easy to install. • A break anywhere along the cable causes all network traffic to stop.

23. Ring Topology • A ring topology forms when you connect a network’s nodes in a circle. • Messages flow in a single direction. • A small packet called a token circulates the ring – a device must have the token to use the network.

24. Star Topology • In a star topology, each device in the network connects to a central hub, which distributes messages from one node to another. • Provides centralized control • Easy expansion • Fault tolerance

25. Hybrid Topology • A hybrid topology in a network employs more than one topology to connect devices. Star Bus topology Star Ring topology

26. Mesh Topology • In a mesh topology, multiple connections are made. • In mission-critical operations, you want as much redundancy as possible so that if one part of the network goes down, the packets can find an alternate path to their destination.

27. Adopting Network Protocols

28. Protocol • A protocol is a set of rules that define how computers communicate with each other. • The International Standards Organization (ISO) developed an international standard called the Open System Interconnection (OSI) Reference Model (OSI/RM).

29. OSI Reference Model • This model comprises of seven layers that describe the way data is shared on a network. • Suppose you just clicked on a link on a Web page. The following slides describe the process from one layer to another. • Data is passed down from Layer 7 to Layer 1, is then transmitted over the medium, and then goes back up from Layer 1 to Layer 7 in the receiving device. • Headers are added at each layer.

30. Layer 7: Application • Through an Application Programming Interface (API), the browser informs the Application Layerof your request. • The Application Layer begins to form the packet that will eventually travel across the network.

31. Layer 6: Presentation • The Presentation Layertranslates the data into a standard network data format. • It can use data compression to streamline the packet so it does not consume unnecessary bandwidth on the network. • It can also encrypt the data for sensitive data transmissions.

32. Layer 5: Session • The Session Layernegotiates the connection that will be made between the two computers exchanging data. • It inserts a checkpoint, which is a marker used to signal that a certain amount of the data has arrived all right.

33. Layer 4: Transport • The Transport Layerworks to ensure that the data arrives reliably at its destination. • If the amount of data is large, the data is split into fragments that are numbered sequentially.

34. Layer 3: Network • The Network Layerorganizes data into datagrams consisting of the data from the Transport Layer and routing information such as the source and destination addresses.

35. Layer 2: Datalink • The Data Link Layertransforms the data into data frames. • It consists of two sublayers: • Logical Link Control(LLC) • Performs error checking and regulates the flow of data. • Media Access Control(MAC) • Handles the actual placement of the packets onto the Physical Layer.

36. CRC • The Data Link layer also calculates a cyclic redundancy check (CRC) based on the information in the frame. • The receiving machine calculates its own CRC and compares it to the value in the frame. If they do not match, the frame is corrupt and discarded.

37. Layer 1: Physical • The Physical Layertransforms the 0’s and 1’s into signals that flow over the transmission media. • At the receiving end, the Physical Layer converts these signals back into 0’s and 1’s and passes them up to the Data Link Layer.

38. Communication

39. To help you remember…

40. Protocol Suites • The term protocol suiterefers to a collection of protocols that work together to conform to a multilayered protocol standard, such as the OSI/RM. • Six major protocol suites follow the OSI/RM: • TCP/IP • NetBEUI • IPX/SPX • AppleTalk • DLC • SNA

41. TCP/IP • TCP/IPis the Internet’s protocol suite. • Transport Control Protocol (TCP) • Manages the Transport Layer • Internet Protocol (IP) • Handles the routing on the Network Layer

42. NetBEUI • NetBEUIstands for NetBIOS Extended User Interface • NetBIOS stands for Network Basic Input/Output System • Not routable

43. IPX/SPX • IPX/SPXstands for Internetwork Packet Exchange (IPX) and Sequenced Packet Exchange (SPX). • Developed by Novell for use with the NetWare network operating system.

44. AppleTalk • AppleTalk is the legacy protocol suite for peer-to-peer networking on local networks of Macintosh computers.

45. DLC • IBM invented Data Link Control(DLC)to enable microcomputers to connect as clients to legacy mainframes. • Still used by Hewlett-Packard printers that have Network Interface Cards(NICs).

46. SNA • Systems Network Architecture(SNA)is a protocol suite for connecting different kinds of networks.

47. Combining Protocols • Most computers run more than one networking protocol. • The process of assigning a protocol to a Network Interface Card (NIC) is called protocol binding. • The binding order is the order in which your computer tries protocols when attempting to communicate over the network.

48. Creating LANs, MANs, and WANs

49. LAN • A local area network(LAN)is the connection of two or more computer devices for networking within a relatively small area.

50. MAN • A metropolitan area network(MAN)connects local networks across a larger geographical region. • The term metropolitan implies that MANs cover an area the size of a city.