1. Copyright 2003 www.ciscopress.com CCNA 1 Chapter 2 Networking Fundamentals By Your Name

2. Copyright 2003 www.ciscopress.com Objectives Networking terminology Bandwidth Networking models

3. Copyright 2003 www.ciscopress.com Data Networks Data networking solutions –Local-area networks –Wide-area networks

4. Copyright 2003 www.ciscopress.com Networking History

5. Copyright 2003 www.ciscopress.com Networking Devices Equipment that connects directly to a network segment is referred to as a device. These devices are broken up into two classifications. The first classification is end-user devices. The second classification is network devices.

6. Copyright 2003 www.ciscopress.com Network Topology Network topology defines the structure of the network. The physical topology, which is the actual layout of the wire or media, and the logical topology, which defines how the media is accessed by the hosts for sending data.

7. Copyright 2003 www.ciscopress.com Network Protocols Protocol suites are collections of protocols that enable network communication from one host through the network to another host. A protocol is a formal description of a set of rules and conventions that govern a particular aspect of how devices on a network communicate.

8. Copyright 2003 www.ciscopress.com LANs Operate within a limited geographic area Allow many users to access high-bandwidth media Provide full-time connectivity to local services Connect physically adjacent devices

9. Copyright 2003 www.ciscopress.com LAN Devices

10. Copyright 2003 www.ciscopress.com WAN Technologies Include Analog modems Integrated Services Digital Network (ISDN) Digital Subscriber Line (DSL) Frame Relay Asynchronous Transfer Mode (ATM) T (US) and E (Europe) carrier series: T1, E1, T3, E3 Synchronous Optical Network (SONET)

11. Copyright 2003 www.ciscopress.com WAN Devices

12. Copyright 2003 www.ciscopress.com Metropolitan-Area Networks (MANs) A MAN is a network that spans a metropolitan area such as a city or suburban area. A MAN usually consists of two or more LANs in a common geographic area.

13. Copyright 2003 www.ciscopress.com Storage-Area Networks (SANs) A SAN is a dedicated, high-performance network used to move data between servers and storage resources. Because it is a separate, dedicated network, it avoids any traffic conflict between clients and servers.

14. Copyright 2003 www.ciscopress.com Virtual Private Networks (VPNs) A VPN is a private network that is constructed within a public network infrastructure such as the global Internet.

15. Copyright 2003 www.ciscopress.com Benefits of VPNs A VPN is a service that offers secure, reliable connectivity over a shared public network infrastructure such as the Internet. VPNs maintain the same security and management policies as a private network. They are the most cost-effective method of establishing a point-to-point connection between remote users and an enterprise customer's network.

16. Copyright 2003 www.ciscopress.com VPN Types There are three main types of VPNs: Intranet VPNs Extranet VPNs Access VPNs

17. Copyright 2003 www.ciscopress.com Intranets and Extranets Intranets are designed to permit access by users who have access privileges to the internal LAN of the organization. Extranets refer to applications and services that are Intranet based, but that use extended, secure access to external users or enterprises.

18. Copyright 2003 www.ciscopress.com Bandwidth

19. Copyright 2003 www.ciscopress.com Importance of Bandwidth

20. Copyright 2003 www.ciscopress.com Digital Bandwidth Two analogies that describe digital bandwidth –Width of a pipe –Number of lanes on a highway Media bandwidth differences –Category 5 UTP – 100 meters maximum physical distance –Multimode (62.5/125um) optical fiber – 2000 meters –Modem – 56 kbps = 0.056 Mbps –T1 – 1.544 Mbps

21. Copyright 2003 www.ciscopress.com Digital Bandwidth (cont.) Data throughput in relation to digital bandwidth –Factors that determine: internetworking devices, type of date being transferred, topology, number of users, user’s computer Data transfer calculation –Estimated time = size of file / bandwidth

22. Copyright 2003 www.ciscopress.com Bandwidth Pipe Analogy

23. Copyright 2003 www.ciscopress.com Bandwidth Highway Analogy

24. Copyright 2003 www.ciscopress.com Bandwidth Measurements

25. Copyright 2003 www.ciscopress.com Media Bandwidth

26. Copyright 2003 www.ciscopress.com Digital Transfer Calculation

27. Copyright 2003 www.ciscopress.com Digital vs. Analog Analog bandwidth is measured by how much of the electromagnetic spectrum is occupied by each signal. In digital signaling, all information is sent as bits, regardless of the kind of information it is.

28. Copyright 2003 www.ciscopress.com Networking Models

29. Copyright 2003 www.ciscopress.com Using Layers to Describe Communication Source, destination, and data packets –All communications originate at a source and travel to a destination. –Information that travels on a network is referred to as a data, packet, or data packet.

30. Copyright 2003 www.ciscopress.com Using Layers to Describe Communication Media –Telephone wires (UTP) –Category 5 UTP (used for 10BASE-T Ethernet) –Coaxial cables –Optical fibers (thin glass fibers that carry light) Protocol –All devices on a network need to speak the same language. –Set of rules that makes communication both possible and more efficient.

31. Copyright 2003 www.ciscopress.com The Purpose of the OSI Reference Model It breaks network communication into smaller, simpler parts that are easier to develop. It facilitates standardization of network components to allow multiple-vendor development and support. It allows different types of network hardware and software to communicate with each other. It prevents changes in one layer from affecting the other layers so that they can develop more quickly. It breaks network communication into smaller parts to make learning it easier to understand.

32. Copyright 2003 www.ciscopress.com Seven Layers of the OSI Reference Model Layer 7: Application Layer 6: Presentation Layer 5: Session Layer 4: Transport Layer 3: Network Layer 2: Data link Layer 1: Physical

33. Copyright 2003 www.ciscopress.com Why a Layered Model?

34. Copyright 2003 www.ciscopress.com Layers with Functions

35. Copyright 2003 www.ciscopress.com The Seven Layers of the OSI Reference Model The application (upper) layers –Layer 7: Application –Layer 6: Presentation –Layer 5: Session The data-flow (lower) layers –Layer 4: Transport –Layer 3: Network –Layer 2: Data link –Layer 1: Physical

36. Copyright 2003 www.ciscopress.com The Application (Upper) Layers Application –User interface –Examples – Telnet, HTTP Presentation –How data is presented –Special processing, such as encryption –Examples – ASCII, EMCDIC, JPEG Session –Keeping different applications’ data separate –Examples – Operating system/application access scheduling

37. Copyright 2003 www.ciscopress.com The Data-Flow (Lower) Layers Transport –Reliable or unreliable delivery –Error correction before transmit –Examples: TCP, UDP, SPX Network –Provide logical addressing which routers use for path determination –Examples: IP, IPX

38. Copyright 2003 www.ciscopress.com The Lower Layers (cont.) Data link –Combines bits into bytes and bytes into frames –Access to media using MAC address –Error detection not correction –Examples: 802.3/802.2, HDLN Physical –Moves bits between devices –Specifies voltage, wire speed, and pinout cables –Examples: EIA/TIA-232, V.35

39. Copyright 2003 www.ciscopress.com The OSI Model Application – Think of browsers. Presentation – Think of common data format. Session – Think of dialogs and conversations. Transport – Think of flow control and reliability. Network – Think of path selection, routing, and logical addressing. Data Link – Think of frames and media access control. Physical – Think of signals and media.

40. Copyright 2003 www.ciscopress.com Peer-to-Peer Communication For data to travel from the source to the destination, each layer of the OSI model at the source must communicate with its peer layer at the destination. During this process, the protocols of each layer exchange information, called protocol data units (PDUs), between peer layers. Each layer of communication on the source computer communicates with a layer-specific PDU, and with its peer layer on the destination computer.

41. Copyright 2003 www.ciscopress.com The TCP/IP Reference Model

42. Copyright 2003 www.ciscopress.com TCP/IP Protocol Graph

43. Copyright 2003 www.ciscopress.com Applications FTP – File Transfer Protocol HTTP – Hypertext Transfer Protocol SMTP – Simple Mail Transfer Protocol DNS – Domain Name System TFTP – Trivial File Transfer Protocol

44. Copyright 2003 www.ciscopress.com OSI Model and TCP/IP Model

45. Copyright 2003 www.ciscopress.com Use of the OSI Model in the CCNA Curriculum

46. Copyright 2003 www.ciscopress.com Encapsulation The lower layers use encapsulation to put the protocol data unit (PDU) from the upper layer into its data field and to add headers and trailers that the layer can use to perform its function.

47. Copyright 2003 www.ciscopress.com Names for Data at Each Layer

48. Copyright 2003 www.ciscopress.com De-Encapsulation When the data link layer receives the frame, it does the following: –It reads the physical address and other control information provided by the directly connected peer data link layer. –It strips the control information from the frame, thereby creating a datagram. –It passes the datagram up to the next layer, following the instructions that appeared in the control portion of the frame.