Chapter 13 Introduction to Networking

1. The Complete A+ Guideto PC Repair 5/e Chapter 13Introduction to Networking

2. Chapter Objectives • Differentiate between peer-to-peer and server-based networks • Identify commonly used network topologies • Compare and contrast types of network cabling • Explain the differences between various network access methods • Explain how Ethernet works • Identify OSI model layers and the network devices that work at each layer

3. Chapter Objectives • Articulate commonly used network protocols • Define the purpose and identification of a MAC address and an IP address • Apply IP addressing concepts • Define the purpose of DHCP and DNS • Configure a computer for network connectivity • Use common network troubleshooting tools • Access a network printer • Define common networking terms

4. Chapter Objectives • Identify and define the function of the basic parts of a wireless network • Distinguish between ad hoc and infrastructure wireless NICs • List the different types of wireless NICs • Explain the purpose of an SSID and channel ID • List the three non-overlapping channel IDs used in wireless networks • Contrast dBd with dBi

5. Chapter Objectives • Define and explain how to perform a basic wireless site survey • Compare and contrast the 802.11a, 802.11b, 802.11g, and 802.11n wireless standards • After completing this chapter you will be able to: • Explain the basic protocols used with email • Describe how to be a proactive technician

6. Networking Overview • Many networks are found all around us. • The network of roads and interstate highways • The telephone network • The electrical network that provides electricity to our homes • The cellular network that allows cell phones to connect to one another as well as connectivity between cell phones and the wired telephone network and the Internet • Air traffic control network • Our network of friends and family

7. Networking Overview Network – Two or more devices capable of communicating and sharing resources between them. • Types of networks 1 PAN – Personal devices such as PDAs, keyboards, mice, headsets, communicate in close proximity through a wired or wireless network. 2 LAN – A group of devices sharing resources in a single area such as a room or a building. MAN – Connectivity of sites within a city. 3 WAN – Communication between LANs on a larger geographic scale—the Internet is the largest. 4

8. Types of Local Area Networks • There are two basic types of LANs, a server-based network and a peer-to-peer network. • Server-based network - Users login to a server, that knows who is authorized to connect to the LAN and what resources the user is authorized to access. • Usually found in businesses comprising of 10 or more computers. • Also known as a client/server network. • Collectively, these servers and client computers are part of one or more domains.

9. Server-Based Network

10. Types of Local Area Networks • Peer-to-Peer Network - A type of LAN wherein each computer user acts as a server. • Each computer stores password and sharing information for its own resources. • Usually has fewer than 10 computers • The more resources that are shared on peer-to-peer network, the more passwords and more cumbersome password management will be. • Workgroup - A term given to a peer-to-peer Windows network. • A workgroup does not use a server to authenticate users during the login process.

11. Peer-to-Peer Network

12. Ethernet LANs Ethernet is the most common type of LAN • The RJ-45 jack is the most common type of Ethernet port. • Ethernet adapters are the most common network cards.

13. Network Topologies Star Topology Extended Star Topology Hierarchical Topology Ring Topology Bus Topology Mesh Topology Network topology is how the network is wired.

14. Network Topologies • Hub- A device used with the universal serial bus or in a star network topology that allows multiple device connections. • A network hub cannot look at each data frame coming through its ports like a switch does. • Switch- In star networks, a Layer two central controlling device. • Looks like a hub • Looks at each data frame as it comes through each port.

15. Tech Tip – Ethernet LANs are wired in a star • The most common network topology used today is the star topology because it is used with Ethernet networks.

16. Network Topologies Topology Bus Hierarchical Mesh Ring Description Not common anymore; takes less cable (cheaper); but with a break in the bus, the network is down. A common design model for businesses with quite a few computers. With a break in the cable, the network still works (very fault tolerant), but it takes a lot of cabling. Expensive and complex—hard to configure. Each network device connects to two adjacent network devices. It is easy to install, but requires expensive parts. A ring topology is used with fiber.

17. Network Topologies Topology Star Extended Star Description The easiest to install, is the most common (because of it being used with Ethernet), and a break in a workstation cable does not affect the rest of the network. More cable is used in wiring a star topology, but the type of cable used is comparatively cheap star topologies are easy to troubleshoot. The Extended Star topology contains multiple hubs or switches. If one hub or switch goes down, only those devices connected to that hub or switch will fail to work. A network cable will connect the device to hub or switch.

18. Network Media Overview • Networks require some type of medium to transmit data. • This medium is normally some type of cable or air. • The most common types of cable are twisted-pair copper and fiber-optic, although some very old networks used coax cable and video networks use coax.

19. Unshielded Twisted-Pair

20. Copper Media • Twisted-Pair Cable – Network cable of eight copper wires twisted into four pairs. Comes shielded and unshielded. • UTP(Unshielded Twisted-Pair)– Most common network cable. Comes in different categories for different uses. • STP(Shielded Twisted-Pair) – Network cable with extra foil to prevent outside noise form interfering with data on the cable. • Crosstalk – A type of EMI where signals from one wire interfere with the data on an adjacent wire.

21. UTP Cable Figure 13.6

22. Copper Media • Plenum cable - A type of cable that is treated with fire retardant materials so it is less of a fire risk. • PVC (polyvinyl chloride) – Cable that has a plastic insulation or jacket that is cheaper and easier to install than plenum cable. • It can have flame-retardant added.

23. UTP Wiring Standards Figure 13.7

24. RJ-45 pin 1 Assignments Figure 13.8

25. UTP Cable Categories

26. Coaxial Cable • Coaxial cable - Type of network cabling used in video networks, older Ethernet networks, as well as mainframe and minicomputer connections. • Has a copper core, surrounded by insulation and shielding from EMI.

27. Coax Cable with Connector Figure 13.9

28. Fiber Media • Fiber-optic cable is made of glass or a type of plastic fiber and is used to carry light pulses. • Fiber-optic cable can be used to connect a workstation to another device, but in industry, the most common use of fiber-optic cable is to connect networks together forming the network backbone. • Fiber-optic cabling has many advantages including security, long distance transmission, and bandwidth.

29. Fiber Media • Single-mode- A type of fiber-optic cabling that sends one light beam down the cable. • Multi-mode- A type of fiber-optic cabling that allows multiple light signals to be sent along the same cable. • Which fiber should I use? • Multi-mode fiber is cheaper and more commonly used than single-mode fiber and is good for shorter distance applications; but single-mode fiber can transmit a signal farther than multi-mode and supports the highest bandwidth.

30. Fiber Connectors

31. Protecting Your Network and Cable Investment • Professional cable management systems keep cables organized. • A secure room or cabinet should be used to store network devices. • If possible network cabling should be installed in conduit or raceways.

32. Ethernet Issues and Concepts • Half-duplex - A serial device setting that allows either the sending or the receiving device to send data, one device at a time. • On a cable, half-duplex is the ability to transmit in both directions but not at the same time. • Full-duplex - A serial device setting that allows the sending and receiving device to send data simultaneously. • On a cable, full-duplex is the ability to transmit data in both directions simultaneously.

33. Ethernet Issues and Concepts • Ethernet networks were originally designed for half-duplex transmission on a 10Mbps bus topology. • The more workstations on the same network, the more collisions occur and the more network slows down. • In addition, with half-duplex Ethernet, less than 50 percent of the 10Mbps available bandwidth could be used because of the collisions and the time it takes for a network frame to transmit across the wire.

34. Ethernet Issues and Concepts • Full-duplex more than doubles the amount of throughput on a network because of the lack of collisions and transmitting both directions simultaneously. • Full-duplex is used when a switch is used to connect network devices together.

35. Tech Tip – Why a switch is better than a hub When a workstation sends data to a hub, the hub broadcasts the data out all ports except for the port the data came in on. A switch, on the other hand, keeps a table of addresses. When a switch receives data, the switch looks up the destination MAC address in the switch table and forwards the data out the port for which it is destined. A switch looks very similar to a hub and it is sometimes hard to distinguish between the two.

36. Network Standards IEEE committees create network stands called the 802 standards.

37. OSI Model • OSI Model (Open Systems Interconnect Model) – A standard for information transfer across a network by the ISO. • The model has seven layers – each layer uses the layer below it, and each layer provides some function to the one above it.

38. OSI Model • The model sets several guidelines or describes • how the different transmission media are arranged and interconnected • how network devices that use different languages communicate with one another • how a network device goes about contacting another network device • how and when data gets transmitted across the network • how data is sent to the correct device • how a receiving device knows if the network data was received properly

39. OSI Model Layers

40. Encapsulated Data in the OSI Model • Bits – encapsulated data found at Layer 1 • Frame - encapsulated data found at Layer 2 • Packet- encapsulated data found at Layer 3 • Segment – encapsulated data found at Layer 4 • Data – any encapsulated info at Layers 5 through 7

41. OSI Model Terms • ISP (Internet service provider)- A vendor that provides connection to the Internet. • Authentication- The process of determining that a network device or person has permission to access a network. • The OSI model is very confusing when you are first learning about networking, but it is very important. Understanding the model helps when troubleshooting a network.

42. Tech Tip – OSI Mnemonic • A mnemonic to help remember the OSI layers. • A • Person • Seldom • Takes • Naps • During • Parties • For example, A in the phrase is to remind you of the application layer. • P in Person is to remind you of the presentation layer, and so on.

43. The TCP/IP Model • A network protocol is a data communication language. • A set of rules for communication between two end devices • A protocol suite is a group of protocols that are designed to work together. • TCP/IP (Transmission Control Protocol/Internet Protocol) – the protocol suite used in networks today. • It is the most common network protocol and is required when accessing the Internet.

44. TCP/IP Model • The TCP/IP model consists of four layers. • Application • Transport TCP/IP Model • Internet • Network Access

45. The TCP/IP Model • The TCP/IP protocol suite consists of many protocols ◘ TCP (Transmission Control Protocol) ◘ IP (Internet Protocol) ◘ DHCP (Dynamic Host Configuration Protocol) ◘ FTP (File Transfer Protocol) ◘ HTTP (HyperText Transfer Protocol)

46. The TCP/IP Model Layers TCP/IP-based application-layer protocols format data specific for the purpose. Is equivalent to the application, presentation, and session layers of the OSI model. Protocols include HTTP, Telnet, DNS, HTTPS, FTP, TFTP, TLS, SSL, POP, SNMP, IMAP, NNTP, and SMTP. Transport-layer protocols add port numbers in the header so the computer can identify which application is sending the data. When data returns, this port number allows the computer to determine into which window on the screen to place the data. Protocols include TCP and UDP. Application Transport Internet Network access Sometimes called the internetwork layer. IP is the most common Internet layer protocol. IP adds a source and destination IP address to uniquely identify the source and destination network devices. Called link layer in the original RFC. Defines how to format the data for the type of network being used. Defines the type of connector used and puts the data onto the network, whether it be voltage levels for 1s and 0s on the copper cable or pulses of light for fiber. The TCP/IP model is a real model. The OSI model is theoretical.

47. The TCP/IP Model Layers

48. Tech Tip – Use netstat to view current connections • To see current connections and associated port numbers, bring up a command prompt and type netstat.

49. Networking Addressing • Ethernet network adapters normally have two types of addresses assigned to them – a MAC address and an IP address. • MAC address (media access control address) – One of two types of addresses assigned to network adapters, used when two devices on the same network communicate. • Known as a Layer two address.

50. MAC Address Network adapter has this address burned into a ROM chip ◘ ◘ Also known as a Layer 2 address ◘ 48-bit address shown in hexadecimal