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Local Area Networking

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  1. Local Area Networking Chapter 21

  2. Overview • In this chapter, you will learn to • Explain network technologies • Explain network operating systems • Install and configure wired networks • Install and configure wireless networks • Troubleshoot networks

  3. Networking Technologies

  4. The Big Questions • How will each computer be identified? • If two or more computers want to talk at the same time, how do you ensure all conversations are understood? • What kind of wire should be used? • How many wires in the cable? How thick? How long? What type of connectors? • How can access to data be controlled? • And the list goes on and on…

  5. A Few Basics • A client machine requests information or services • Network interface card (NIC) defines the client • Breaks data into smaller data units (packets) • A medium to connect the devices is needed • Wired or wireless • Operating system needs to be network aware • A server provides information or services to the client

  6. Topology • Bus topology • All computers connect to the network via a main line called a bus cable • Ring topology • All computers attach to a central ring of cable

  7. Topology • Star topology • Computers on the networkconnect to a central wiring point (often a switch or a hub) • Mesh topology • Each computer has a dedicated line to everyother computer

  8. Essentials CompTIA A+Essentials Getting the Right Sound Card Packets/Frames and NICs

  9. Packets, Frames, and NICs • Data is broken up into small pieces and moved about the network • Data moved in chunks called packets or frames • Every network interface card (NIC) has a built-in identifier called a Media Access Control (MAC) address • Designed to be unique • Uses 48-bit long address • Burned into a chip on the card

  10. Packet Fields • Packets contain the following fields • MAC address of destination NIC • MAC address of source NIC • Data • Data check or cyclic redundancy check (CRC) used to verify the data’s integrity

  11. Protocols • Protocols are sets of rules • May be used to define packet types, cabling and connectors, addresses, and much more • A hardware protocol defines how to get data from one computer to another • Ethernet is the dominant standard for today’s networks • Cables include coaxial, unshielded twisted pair, fiber optic • Token Ring was developed by IBM but is losing popularity

  12. Coaxial Ethernet • Early Ethernet networks used coaxial cable (or just coax) • Composed of a center cable surrounded by insulation, a shield of braided cable, and an outside protective cover • A different type of coaxial cable is used by your VCRand TV

  13. Thick Ethernet—10Base5 • Thick Ethernet cable used • RG-8 (Radio Grade) cable • 10Base5 • 10 means data is transferred at 10 Mbps • 5 means the maximum length of the cable is 500 meters • Uses a bus topology • Computers are connectedone to another • Every computer receives every packet of information

  14. CSMA/CD • Carrier sense multiple access/collision detection (CSMA/CD) • To prevent collisions when there is multiple access to a cable • Computers first do a carrier sense (listen to the cable for traffic) before trying to send data

  15. CSMA/CD • If two computers talk (try to send data) at the same time • A collision results that corrupts the data • Computers then decide when to resend the data

  16. Reflection and Termination • Signals traveling along a wire will bounce back when they get to the end • This is called reflection • Can corrupt signal • A terminator absorbs the reflection When an electrical signal reaches the end of a wire… When an electrical signal reaches the end of a terminated wire… Some of the signalis reflected back There is no reflection

  17. Connections • Thicknet marked every 2.5 meters • Devices are connected at these points • Vampire connector pierces the cable • It is also a transceiver that transmits and receives data, sometimes called an access unit interface (AUI) that connects to a Digital, Intel, or Xerox (DIX) connector • Thicknet uses a bus topology • Break in the cable takes down the whole network

  18. Thicknet Connections

  19. Thin Ethernet—10Base2 • Thin Ethernet is also known as Thinnet • Uses RG-58 coax • Limited to 30 devices per segment • Cable length limited to 185 meters • Thinner and cheaper than Thicknet • Transceiver built into NIC • Uses twist-on BNC connectors • Uses terminators

  20. UTP Ethernet • 10/100/1000BaseT (10xBaseT) • Modern networks use UTP Ethernet • 10BaseT runs at 10 Mbps • 100BaseT runs at 100 Mbps • 1000BaseT (Gigabit) runs at 1000 Mbps • Uses a star bus topology • Uses unshielded twisted pair (UTP) cabling

  21. Star Bus Topology • Most common topology used is a star bus • All devices are connected to a central device • Can be a hub or a switch • Switch makes each port a separate network • Limits collisions • Helps bandwidth

  22. Unshielded Twisted Pair • UTP is predominant type of cabling used • Pairs of wires are twisted together in an unshielded cable • UTP cables come in categories (CATs) that define the maximum speed data can be transferred • Called bandwidth • CAT5, CAT5e, and CAT6 are most common today

  23. Implementing 10xBaseT • Requires at least two pairs of wires • One for receiving and one for sending • Cables use RJ-45 connectors • RJ-11 for telephones • The Telecommunications Industry Association/ Electronics Industries Alliance (TIA/EIA) has two standards for connecting RJ-45 connectors • TIA/EIA 568A and TIA/EIA 568B • Use either but be consistent • Wires are color-coded 1 8

  24. Combo Cards • Ethernet networks share same language • Many NICs run at 10 or 100 Mbps • Some NICs have BNCand RJ-45 ports • Most NICs built into motherboards are autosensing • Run at speed of network

  25. Hubs and Switches • Each PC is connected to a hub or switch in a 10xBaseT network • To add a device, simply run another cable to the hub or switch from the device • The maximum separation between the device and the hub or switch is 100 meters • Maximum of 1024 PCs per hub or switch • Hubs act as repeaters that regenerate the signal before they send it back out to other ports • Hubs come in 4, 8, 16, or 24 ports

  26. Duplex and Half-Duplex • Modern NICs can both send and receive data at the same time • Called full duplex • Older NICs could send and receive data but not at the same time • Called half duplex • Similar to a walkie-talkie

  27. Fiber Optic Ethernet • Uses light instead of electricity • Immune to electrical interference • Signals can travel up to 2000 meters • Most Ethernet uses 62.5/125 multimode cable • Uses two cables • Uses SC (square-shaped) or ST (round) connectors • Common standards • 10BaseFL and 100BaseFL • Usually reserved for data centers due to expense

  28. Token Ring • Developed by IBM • Uses a star ring topology • Incompatible with Ethernet • Data travels in a ring • Uses token passing • A free token circulates the ring • A device may send data only when it has the token

  29. Implementing Token Ring • Legacy Token Ring ran at 4 Mbps or 16 Mbps using IBM Type 1 cable • Two-pair, shielded twisted pair(STP) cable • Today’s Token Ring networks may use UTP or STP • STP comes in various types

  30. Token Ring Connectors • Token Ring cables use an IBM-type Data Connector (IDC) • Universal Data Connectors (UDC) designed to plug into each other • Uses a special hub called a multistation access unit (MSAU or MAU)

  31. Other Connections • Can connect two PCs together • Parallel/serial • Using crossover IEEE 1284 cable for parallel ports • Use an RS-232 cable for serial ports • FireWire • Network aware • Just connect • USB • Not quite as easy as FireWire but possible

  32. IT Technician CompTIA A+Technician Network Operating System

  33. Client/Server • In a client/server environment, one machine is dedicated as a resource • Shared over the network • Uses a special network operating system (NOS) • Optimized for sharing files and printers or other resources • Protects access to the data or resources using security • Called the server • All other machines are clients or workstations • Novell NetWare is an enterprise-level NOS

  34. Peer-to-Peer • In a peer-to-peer network, any machine on the network can act as client or server • Peer-to-peer network operating systems include • Windows 2000/XP • Limited to 10 users accessing a file at one time • Microsoft recommends no more than 15 PCs • Useful for small networks only • Limited security • Also referred to as a workgroup

  35. Peer-to-Peer • User must log on to each individual computer • Multiple computers, multiple logons

  36. Domain-Based • User logs onto domain controller • One user, one logon • Can access all computers (unless locked down with security)

  37. Domain-Based • Servers on the network may play one or several roles • Domain controller (holds the security database) • File server • Print server • Fax server • Remote access services (RAS) server • Application server • Web server

  38. Administrator Account • Special user account that has complete and absolute power over entire system • Password should be protected • Joining a workgroup or becoming part of a domain is relatively easy • Need Administrator access

  39. Joining a Workgroup or Domain in Windows 98 • Joining a workgroup or becoming part of a domain is relatively easy • Need Administrator access • Select computer properties

  40. Protocols • Network protocol software • Takes incoming data received by the network card • Keeps it organized • Sends it to the application that needs it • Takes outgoing data from application and hands it over to the NIC to be sent out over the network • The most common protocols used are • NetBEUI—nonroutable, rarely used today • IPX/SPX—used by Novell • TCP/IP—used on Internet and most networks • AppleTalk—proprietary Apple protocol

  41. Client software Needed to access data and resources on a network Windows installs Client for Microsoft Networks Server software Any Windows PC may be turned into a server by enabling sharing of files, folders, and printers Client and Server Software

  42. Installing and Configuring a Wired Network

  43. Network Connectivity • To connect to a network you need • Network interface card • Physical hardware that connects the PC to the network wire • Protocol • The language the devices use to communicate • Network client • Allows the computer system to speak to the protocol • To share resources, enable Microsoft’s File and Print Sharing

  44. Installing a NIC • When choosing a NIC, there are three requirements • Must run at the proper speed (many NICs run at more than one speed) • Must be for the proper technology • Ethernet, Token Ring, fiber optic (FDDI) • Must fit into your expansion slot • PCI • If NIC does not autoinstall, then use the Add Hardware Wizard in Control Panel

  45. Configuring a Network Client • You need a network client for each type of server NOS • Client for Microsoft Networks • Right-click My Network Places (or Network Neighborhood) and choose Properties • Double-click the Local Area Connection icon (or choose Create a New Network Connection) and select Properties • Client for Microsoft Networks is automatically installed when you install a NIC in Windows • Client Service for NetWare • Provides access to file and print services on NetWare servers

  46. Client for Microsoft Networks

  47. NetBEUI in Windows 2000 • NetBEUI • Windows 2000: Start  Settings  Network and Dial-up Connections  Double-click the Local Area Connection icon • Click the Properties button • Click Install button, highlight Protocols, and click Add  NetBEUI • Windows XP has dropped support for NetBEUI

  48. NetBEUI • NetBEUI • Not routable (can’t go through routers) • Rarely used today

  49. NWLink • Microsoft’s implementation of IPX/SPX • You’ll also need to install Client Services for NetWare • Install the same way you install NetBEUI but choose NWLink instead

  50. Configuring TCP/IP • TCP/IP is the most widely used protocol suite in networks today • It is the protocol of choice for the Internet but is also used on private networks • TCP/IP is installed just like NetBEUI and NWLink—simply choose Internet Protocol (TCP/IP) • You’ll need to configure an IP address and a subnet mask at the very least