Chapter 5 LANs and WANs

Network Building Blocks Chapter 5: LANs and WLANs 2  Network Classifications  LAN Standards  Network Devices  Clients, Servers, and Peers  Physical Topology  Network Links  Communications Protocols

Network Classifications Chapter 5: LANs and WLANs 3  Personal Area Network (PAN) – interconnection of personal digital devices  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

LAN Standards Chapter 5: LANs and WLANs 4  LAN technologies are standardized by the Institute of Electrical and Electronics Engineers (IEEE) Project 802 – Local Network Standards  IEEE – current standard  ARCnet  Token Ring  FDDI  Ethernet – most common today thru Wi-Fi

Network Devices Chapter 5: LANs and WLANs 5  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

Network Devices Chapter 5: LANs and WLANs 6

Clients, Servers, and Peers Chapter 5: LANs and WLANs 7  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

Physical Topology Chapter 5: LANs and WLANs 8  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 (hardware)  Gateway is a generic term for any device or software code used to join two networks (software)

Network Links Chapter 5: LANs and WLANs 9  A communications channel, or link, is a physical path or frequency for signal transmissions  Bandwidth is the transmission capacity of a communications channel  Broadband (cable)  Narrowband (dsl)

Broadband - Structure Chapter 5: LANs and WLANs 10

Communications Protocols Chapter 5: LANs and WLANs 11  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

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

Communications Protocols Chapter 5: LANs and WLANs 13  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

Question Chapter 5: LANs and WLANs 14  Networks come in many sizes and use many different technologies, yet they all need to communicate with each other. What is the key to network intercommunication?  A. Packet switching  B. Network protocols  C. Network topology  D. Peer-to-peer technology

Wired Networks Chapter 5: LANs and WLANs 15  Wired Network Basics  HomePNA and Powerline Networks  Ethernet  Ethernet Equipment  Ethernet Setup

Wired Network Basics Chapter 5: LANs and WLANs 16  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

HomePNA and Powerline Networks Chapter 5: LANs and WLANs 17  HomePNA networks utilize existing telephone wiring or coaxial cables to connect network devices  Special NICs and cables are required  A powerline network uses premises electrical wiring to form the infrastructure for a LAN

Ethernet Chapter 5: LANs and WLANs 18  Simultaneously broadcasts data packets to all network devices  IEEE  CSMA/CD protocol  Vary in speed from 10Mbps to 100Gbps

Ethernet Chapter 5: LANs and WLANs 19 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.

Ethernet Equipment Chapter 5: LANs and WLANs 20

Ethernet Equipment Chapter 5: LANs and WLANs 21  Ethernet adapter (designed to support the Ethernet protocols)  Network hub  Network switch  Network router  RJ45 connector

Ethernet Setup Chapter 5: LANs and WLANs 22

Ethernet Setup Chapter 5: LANs and WLANs 23

Ethernet Setup Chapter 5: LANs and WLANs 24 Most routers are configured using a browser. You should change the network administrator password, then verify that DHCP is enabled

Question Chapter 5: LANs and WLANs 25  Suppose you’re setting up a network in your home or apartment. You want all of the computers to access the cable modem that provides Internet access. What is the one additional component that you should purchase to tie the network together?  A. A router  B. A network interface card  C. A file server  D. A HomePlug Ethernet port

Wireless Networks Chapter 5: LANs and WLANs 26  Wireless Basics  Bluetooth  Wi-Fi  Wi-Fi Equipment  Wi-Fi Setup

Wireless Basics Chapter 5: LANs and WLANs 27  A wireless network transports data from one device to another without cables or wires  RF signals(radio frequencies)  Transceiver  Microwaves  Infrared light  Slower than wired networks  Security concerns

Bluetooth Chapter 5: LANs and WLANs 28  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

Chapter 5: LANs and WLANs 29

Wi-Fi Chapter 5: LANs and WLANs 30  Wireless networking technologies that are compatible with Ethernet  MIMO technology uses two or more antennas to send multiple sets of signals

Wi-Fi Equipment Chapter 5: LANs and WLANs 31

Wi-Fi Equipment Chapter 5: LANs and WLANs 32  If your computer is not pre-equipped with wireless circuitry, you can purchase and install a Wi-Fi adapter

Wi-Fi Equipment Chapter 5: LANs and WLANs 33  Wireless network setups  Wireless ad-hoc network  Wireless infrastructure network  Wireless access point  Wireless router

Wi-Fi Setup Chapter 5: LANs and WLANs 34  Set up the router  Connect to the router with a computer  Configure the router  Access the router setup utility  Create a new router password

Wi-Fi Setup Chapter 5: LANs and WLANs 35  Enter an SSID (service set ID) for the network  Activate WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access), or PSK (pre-shared Key) and create an encryption key  Set up the wireless workstations  Connect an Internet access device

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Using LANs Chapter 5: LANs and WLANs 37  LAN Advantages and Challenges  Sharing Files  Sharing Printers  LAN Parties  Troubleshooting

LAN Advantages and Challenges Pros: Chapter 5: LANs and WLANs 38  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

LAN Advantages and Challenges Cons: Chapter 5: LANs and WLANs 39  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

Sharing Files Chapter 5: LANs and WLANs 40  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

Sharing Files Chapter 5: LANs and WLANs 41

Sharing Files Chapter 5: LANs and WLANs 42

Sharing Printers Chapter 5: LANs and WLANs 43  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

Sharing Printers Chapter 5: LANs and WLANs 44 You can designate the printer attached to your computer as sharable over the network.

LAN Parties Chapter 5: LANs and WLANs 45  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

Troubleshooting Chapter 5: LANs and WLANs 46  Network problems can stem from a variety of sources  Cables  Signal strength  Security  Interference  Network devices  Settings

Question Chapter 5: LANs and WLANs 47  There are many ways to share files among the computers on a network. Which one of the following is the LEAST secure way to share files?  A. Use a file server.  B. Activate file sharing for the root directory of all the computers in the network.  C. Designate specific folders on your computer as shared.  D. Put files you want to share in the Public folder.

Security Through Encryption Chapter 5: LANs and WLANs 48  Wi-Fi Security  Encryption

Wi-Fi Security Chapter 5: LANs and WLANs 49  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

Wi-Fi Security Chapter 5: LANs and WLANs 50  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  PSK (Pre-shared Key)  Activate encryption by using a wireless network key

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Encryption Chapter 5: LANs and WLANs 52  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

Encryption Chapter 5: LANs and WLANs 53  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

Encryption Chapter 5: LANs and WLANs 54  Public key encryption (PKE) eliminates key-distribution problem, by using one key to encrypt a message and another key to decrypt the message

Encryption Chapter 5: LANs and WLANs 55  When personal computer users want to encrypt or other documents, they turn to public key encryption software called PGP (Pretty Good Privacy) software

Question Chapter 5: LANs and WLANs 56  As part of the process of setting up a wired network, what should you remember to do?  A. Assign an IP address to each network device.  B. Remove the Ethernet card from any computer that has one.  C. Enable wireless security.  D. Disable the SSID.

FastPoll True/False Questions Answer A for True and B for False Chapter 5: LANs and WLANs 57  In a network, a server is a computer that provides services to other computers called peers.  Star, ring, and mesh are examples of network topologies.  When you send an message over a network, it is chopped up into packets.  The IP address assigned to your computer on the Internet is derived from your computer’s MAC address.  Some network technologies use home telephone or electric cabling for computer networks.

FastPoll True/False Questions Answer A for True and B for False Chapter 5: LANs and WLANs 58  The most popular type of wired network is Ethernet.  Network speeds are measured in megabytes and gigabytes.  Many wireless networks use radio waves to transmit data.  Bluetooth is a wireless technology used for WANs.

FastPoll True/False Questions Answer A for True and B for False Chapter 5: LANs and WLANs 59  A wireless infrastructure network uses a centralized broadcasting device, such as a wireless access point or router.  Wireless networks are less secure than wired networks.  WEP, WPA, and PSK are examples of Wi-Fi networks.  Public key encryption uses a public key to encrypt messages, but a private key is required to decrypt messages.