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Local Area Networking. Chapters 21. 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. Networking Technologies. The Big Questions.
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Local Area Networking Chapters 21
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
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…
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
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
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
Essentials CompTIA A+Essentials Getting the Right Sound Card Packets/Frames and NICs
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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)
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
IT Technician CompTIA A+Technician Network Operating System
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
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
Peer-to-Peer • User must log on to each individual computer • Multiple computers, multiple logons
Domain-Based • User logs onto domain controller • One user, one logon • Can access all computers (unless locked down with security)
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
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
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
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
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
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
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
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
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
NetBEUI • NetBEUI • Not routable (can’t go through routers) • Rarely used today
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
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