1. LANs and WLANs Chapter 5

2. 5 Chapter 5: LANs and WLANs 2 Chapter Contents  Section A: Network Building Blocks  Section B: Wired Networks  Section C: Wireless Networks  Section D: Using LANs  Section E: Security Through Encryption

3. 5 SECTION A Chapter 5: LANs and WLANs 3 Network Building Blocks  Network Classifications  LAN Standards  Network Devices  Clients, Servers, and Peers  Physical Topology  Network Links  Communications Protocols

4. 5 Chapter 5: LANs and WLANs 4 Network Classifications  Personal Area Network (PAN) – interconnection of personal digital devices  Neighborhood Area Network (NAN) – connectivity spread over several buildings  Local Area Network (LAN) – usually connects computers in a single building  Metropolitan Area Network (MAN) – public high- speed network with range of about 50 miles  Wide Area Network (WAN) – consists of several smaller networks

5. 5 Chapter 5: LANs and WLANs 5 LAN Standards  LAN technologies are standardized by the Institute of Electrical and Electronics Engineers (IEEE) Project 802 – Local Network Standards –IEEE 802.3 –Ethernet

6. 5 Chapter 5: LANs and WLANs 6 Network Devices  Each connection point on a network is referred to as a node  To connect to a LAN, a computer requires network circuitry, sometimes referred to as a network interface card (NIC)  A networked peripheral, or network-enabled peripheral, is any device that contains network circuitry to directly connect to a network  A network device, or network appliance, is any electronic device that broadcasts network data, boosts signals, or routes data to its destination

7. 5 Chapter 5: LANs and WLANs 7 Network Devices

8. 5 Chapter 5: LANs and WLANs 8 Clients, Servers, and Peers  Network devices can function as clients or as servers –Application server –File server –Print server  Networks that include one or more servers can operate in client/server mode

9. 5 Chapter 5: LANs and WLANs 9 Physical Topology  The arrangement of devices in a network is referred to as its physical topology –Star –Ring –Bus –Mesh –Tree  Two similar networks can be connected by a device called a bridge  Gateway is a generic term for any device or software code used to join two networks

10. 5 Chapter 5: LANs and WLANs 10 Network Links  A communications channel, or link, is a physical path or frequency for signal transmissions  Bandwidth is the transmission capacity of a communications channel –Broadband –Narrowband

11. 5 Chapter 5: LANs and WLANs 11 Communications Protocols  Rules for efficiently transmitting data from one network node to another –Divide messages into packets –Affix addresses to packets –Initiate transmission –Regulate flow of data –Check for transmission errors –Acknowledge receipt of transmitted data

12. 5 Chapter 5: LANs and WLANs 12 Communications Protocols  A packet is a “parcel” of data that is sent across a computer network –Circuit-switching technology vs. packet switching technology

13. 5 Chapter 5: LANs and WLANs 13 Communications Protocols  Every packet that travels over a network includes the address of its destination device  A MAC address is a unique number assigned to a network interface card when it is manufactured  An IP address is a series of numbers used to identify a network device  IP addresses can also be obtained through DHCP

14. 5 SECTION B Chapter 5: LANs and WLANs 14 Wired Networks  Wired Network Basics  HomePNA and Powerline Networks  Ethernet  Ethernet Equipment  Ethernet Setup

15. 5 Chapter 5: LANs and WLANs 15 Wired Network Basics  A wired network uses cables to connect network devices  Wired networks are fast, secure, and simple to configure  Devices tethered to cables have limited mobility

16. 5 Chapter 5: LANs and WLANs 16 HomePNA and Powerline Networks  HomePNA networks utilize existing telephone wiring to connect network devices –Special NICs and cables are required  Powerline networks transmit data over electrical wiring as low-frequency radio waves

17. 5 Chapter 5: LANs and WLANs 17 Ethernet  Simultaneously broadcasts data packets to all network devices –IEEE 802.3 –CSMA/CD protocol  Vary in speed from 10Mbps to 10Gbps

18. 5 Chapter 5: LANs and WLANs 18 Ethernet On an Ethernet, data travels on a first come, first served basis. If two workstations attempt to send data at the same time, a collision occurs. That data must be resent.

19. 5 Chapter 5: LANs and WLANs 19 Ethernet Equipment Checking a workstation for an Ethernet port

20. 5 Chapter 5: LANs and WLANs 20 Ethernet Equipment  Ethernet adapter (designed to support the Ethernet protocols)  Network hub  Network switch  Network router  RJ45 connector

21. 5 Chapter 5: LANs and WLANs 21 Ethernet Setup

22. 5 Chapter 5: LANs and WLANs 22 Ethernet Setup

23. 5 Chapter 5: LANs and WLANs 23 Most routers are configured using a browser. You should change the network administrator password, then verify that DHCP is enabled

24. 5 SECTION C Chapter 5: LANs and WLANs 24 Wireless Networks  Wireless Basics  Bluetooth  Wi-Fi  Wi-Fi Equipment  Wi-Fi Setup

25. 5 Chapter 5: LANs and WLANs 25 Wireless Basics  A wireless network transports data from one device to another without cables or wires –RF signals Transceiver –Microwaves –Infrared light  Slower than wired networks  Security concerns

26. 5 Chapter 5: LANs and WLANs 26 Bluetooth  Bluetooth is a short-range, wireless network technology designed to make its own connections between electronic devices, without wires, cables, or any direct action from a user

27. 5 Chapter 5: LANs and WLANs 27 Wi-Fi  Wireless networking technologies that are compatible with Ethernet  MIMO technology uses two or more antennae to send multiple sets of signals

28. 5 Chapter 5: LANs and WLANs 28 Wi-Fi Equipment

29. 5 Chapter 5: LANs and WLANs 29 Wi-Fi Equipment  If your computer is not pre-equipped with wireless circuitry, you can purchase and install a Wi-Fi card

30. 5 Chapter 5: LANs and WLANs 30 Wi-Fi Equipment  Wireless network setups –Wireless ad-hoc network –Wireless infrastructure network Wireless access point Wireless router

31. 5 Chapter 5: LANs and WLANs 31 Wi-Fi Setup  Set up the router  Connect to the router with a computer  Configure the router  Access the router setup utility  Create a new router password

32. 5 Chapter 5: LANs and WLANs 32 Wi-Fi Setup  Enter an SSID for the network  Activate WEP, WPA, or WPA2 and create an encryption key  Set up the wireless workstations  Connect an Internet access device

33. 5 Chapter 5: LANs and WLANs 33 Wi-Fi Setup

34. 5 SECTION D Chapter 5: LANs and WLANs 34 Using LANs  LAN Advantages and Challenges  Sharing Files  Sharing Printers  LAN Parties  Troubleshooting

35. 5 Chapter 5: LANs and WLANs 35 LAN Advantages and Challenges  LANs enable people to work together  Sharing networked software can reduce costs  Sharing data on a LAN can increase productivity  Sharing networked hardware can reduce costs  Sharing networked hardware can provide access to a wide range of services and specialized peripheral devices

36. 5 Chapter 5: LANs and WLANs 36 LAN Advantages and Challenges  Resources become unavailable when network malfunctions  Networks may be vulnerable to unauthorized access –More vulnerable than standalone computers  Wireless networks can be tapped from a “snooping” computer  Networked computers are susceptible to an increasing number of worms, Trojan horses, and blended threats

37. 5 Chapter 5: LANs and WLANs 37 Sharing Files  If you use Windows, it automatically detects available LANs any time you turn on a workstation  To connect to a shared resource, you might be asked for a user ID and password

38. 5 Sharing Files Chapter 5: LANs and WLANs 38

39. 5 Chapter 5: LANs and WLANs 39 Sharing Files

40. 5 Chapter 5: LANs and WLANs 40 Sharing Printers  Three setups allow for printer sharing: –Set up printer sharing using a workstation printer –Set up printer sharing using a print server –Install printer with built-in networking

41. 5 Sharing Printers Chapter 5: LANs and WLANs 41 You can designate the printer attached to your computer as sharable over the network.

42. 5 Chapter 5: LANs and WLANs 42 LAN Parties  A LAN party is a gathering of people who connect their own computers to a LAN, usually to play multiplayer computer games –No special hardware usually is required –Game must have multiplayer capability

43. 5 Chapter 5: LANs and WLANs 43 Troubleshooting  Network problems can stem from a variety of sources –Cables –Signal strength –Security –Interference –Network devices –Settings

44. 5 SECTION E Chapter 5: LANs and WLANs 44 Security Through Encryption  Wi-Fi Security  Encryption

45. 5 Chapter 5: LANs and WLANs 45 Wi-Fi Security  Wireless networks are much more susceptible to unauthorized access and use than wired networks  LAN jacking, or war driving, is the practice of intercepting wireless signals by cruising through an area

46. 5 Chapter 5: LANs and WLANs 46 Wi-Fi Security  An offshoot of war driving is a gambit called war chalking

47. 5 Chapter 5: LANs and WLANs 47 Wi-Fi Security  Wireless encryption scrambles data transmitted between wireless devices and then unscrambles the data only on devices that have a valid encryption key –WEP (Wired Equivalent Privacy) –WPA (Wi-Fi Protected Access) –WPA2  Activate encryption by using a wireless network key

48. 5 Chapter 5: LANs and WLANs 48 Wi-Fi Security

49. 5 Chapter 5: LANs and WLANs 49 Encryption  Encryption transforms a message so that its contents are hidden from unauthorized readers –Plaintext has not yet been encrypted –An encrypted message is referred to as ciphertext  Decryption is the opposite of encryption –Cryptographic algorithm –Cryptographic key

50. 5 Chapter 5: LANs and WLANs 50 Encryption  Weak vs. strong encryption  AES (Advanced Encryption Standard)  Encryption methods can be broken by the use of expensive, specialized, code-breaking computers –Brute-force method

51. 5 Chapter 5: LANs and WLANs 51 Encryption  Public key encryption (PKE) eliminates key- distribution problem, by using one key to encrypt a message and another key to decrypt the message

52. 5 Chapter 5: LANs and WLANs 52 Encryption  When personal computer users want to encrypt e-mail or other documents, they turn to public key encryption software called PGP (Pretty Good Privacy) software

53. Chapter 5 Complete LANs and WLANs