Networking
Networking. Chapter 9. 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. Sneakernet.
Networking
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Presentation Transcript
Networking Chapter 9
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
Sneakernet • To share files used to require making copies to a floppy and running them over to someone else…sneakernet • A way needed to be devised for computers to share information and resources • A network is two or more computers connected together to share resources
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 to connect the computers together? • How many wires in the cable? How thick? How long? What type of connectors? • How can access to data and peripherals be controlled? • And the list goes on and on…
A Few Basics • A client machine requests information or services • Uses a network interface card (NIC) to define the client on the network and to physically make a connection • A medium to connect the devices is needed • Cable or wireless • The operating system needs to understand how to network • A server provides information or services to the client
Packets, Frames, and NICs • Data is broken up into small pieces and moved about the network in chunks called packets or frames • Every network interface card (NIC) has a built-in identifier called a Media Access Control (MAC) address • No two NICs have the same MAC address anywhere in the world • Burned into a chip on the card
MAC Address • Start Programs Accesories System Tools System Information
Packet Fields • Packets contain the following fields • MAC address of the network card that it is being sent to • MAC address of the network card that sent the packet • 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 • Coaxial • Unshielded twisted pair • Fiber optic • Token Ring was developed by IBM but is loosing 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 VCR and TV
Thick Ethernet – 10Base5 • Thick Ethernet cable (Thicknet) is used in the 10Base5 Ethernet specification • Called RG-8 (Radio Grade) cable • 10Base5 • 10 means that data is transferred at 10 Mbps • Base refers to baseband signaling • 5 means the maximum length of the cable is 500 meters • Uses a bus topology where all devices attach to a single cable • Computers are connected one to another • Every computer receives every packet of information
CSMA/CD • Carrier Sense Multiple Access/Collision Detection (CSMA/CD) is a method used by computers to share the same cable • If two computers talk (try to send data) at the same time, a collision results that corrupts the data
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 • Even though the computers listen before sending data, it is possible that two computers listened at about the same time, heard nothing, and then sent data – resulting in a collision • Computer NICs have collision detection circuitry that alerts them to a collision
Reflection and Termination • Signals traveling along a wire will bounce back when they get to the end – called reflection • As a result a terminator is installed on the ends of the cable to absorb the signal to prevent it from reflecting back – which would corrupt the signal
Connections • Thicknet cable is marked every 2.5 meters • Devices are connected only at these marks by using a vampire connector that pierces the cable to make a connection • It is also a transceiver that transmits and receives data, sometimes called an access unit interface (AUI) that connects to a Digital, Intel, Xerox (DIX) connector • Thicknet uses a bus topology • If there’s a break in the cable, the whole network goes down
Thin Ethernet – 10Base2 • Thin Ethernet is also known as Thinnet • Uses RG-58 coax cable • Limited to 30 devices per segment • Cable length limited to 185 meters • Thinner and cheaper than Thicknet • Transceiver is built into the network card • Uses twist-on BNC connectors • Uses terminators
UTP Ethernet – 10BaseT • Modern networks use UTP Ethernet • Modern networks do not use Thicknet or Thinnet • 10BaseT runs at 10 Mbps • 100BaseT runs at 100 Mbps • 1000BaseT (Gigabit) runs at 1000 Mbps • Use a star bus topology • Uses unshielded twisted pair (UTP) cabling
Star Bus Topology • Most common topology used is a star bus • In a star topology all devices are connected to a central device called a hub • Multiple hubs are connected together in a bus topology • Together they form a star bus topology • Hubs have been replaced by switches that conserve bandwidth
Unshielded Twisted Pair • UTP is the predominant type of cabling used today • Pairs of wires are twisted together in an unshielded cable • UTP cables come in categories (CATs) that define the maximum speed at which data can be transferred (called bandwidth) • CAT5, CAT5e, and CAT6 are most common today
Implementing 10*BaseT • Requires at least two pairs of wires – one for receiving and one for sending • Cables use special RJ-45 connectors • The Telecommunications Industry Assciation/ Electronics Industries Alliance (TIA/EIA) has two standards for connecting the RJ-45 connectors • TIA/EIA 568A and TIA/EIA 568B • Use either – just be consistent • Wires are color-coded
Combo Cards • All Ethernet networks share the same language • Many NICs will run at either 10 or 100 Mbps • Some NICs have both BNC and RJ-45 ports
Hubs and Switches • Each PC is connected to a hub or switch in a 10*BaseT network • To add a device, just 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 • Hubs act as a repeater that regenerates the signal before it sends it back out 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 • NICs and switches use autosensing to decide how to operate
Fiber Optic Ethernet • Fiber optic cable uses light instead of electricity • Immune to electrical interference • Signals can travel up to 2,000 meters • Most Ethernet uses 62.5/125 multimode cable • Uses two cables • Uses SC (square-shaped) or ST (round) connectors • Common standards are 10BaseFL and 100BaseFX • Usually reserved for the backbone due to its 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 cables use an IBM-type Data Connector (IDC) or Universal Data Connector (UDC) designed to plug into each other • Uses a special hub called a multistation access unit (MSAU or MAU)
Parallel/Serial Connections • All versions of Windows have software that allows two (and only two) PCs to connect together via their parallel or serial ports • Use a crossover IEEE 1284 cable for parallel ports • Use an RS-232 cable for serial ports
Client/Server • In a client/server environment one machine is dedicated as a resource to be 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 features • 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 all machines on the network may act as a client or server • Peer-to-peer network operating systems include • Windows 98/Me • Windows 2000/XP • Limited to 10 users accessing a file at one time • Useful for small networks only • Lacks security • Users are part of workgroups
Domain-Based • In a peer-to-peer network you must log in to each server you wish to access • In a domain-based network you log into the network just once to access resources throughout the network • 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
Domain Controllers • Domain Controllers keep the security database of users and passwords • Directory services are used to store user names and passwords • In Windows 2000 and 2003 server, it is called Active Directory • In Novell NetWare it is called NetWare Directory Services (NDS)
Administrative Tools Administrative Tools in Windows XP Professional Administrative Tools in Windows 2000 Server
Administrator Account • The administrator account is a special user account that has complete and absolute power over the entire system • Joining a workgroup or becoming part of a domain is relatively easy in any version of Windows
Protocols • Network protocol software • Takes the incoming data received by the network card • Keeps it organized • Sends it to the application that needs it • Takes outgoing data from the application and hands it over to the NIC to be sent out over the network • The most common protocols used are • NetBEUI • IPX/SPX • TCP/IP • AppleTalk
NetBEUI • NetBIOS Extended User Interface (NetBEUI) • Small size • High speed • Not routable • Limited to small networks
IPX/SPX • Internetwork Packet Exchange/ Sequenced Packet Exchange (IPX/SPX) • Developed by Novell • Routable • NWLink is Microsoft’s version
TCP/IP • Transmission Control Protocol/Internet Protocol (TCP/IP) • Developed by the U.S. Department of Defense • Used in networks of all sizes • Used on the Internet
AppleTalk • AppleTalk is a proprietary protocol developed by Apple • Used to communicate with older Apple Computers • Apple’s Macintosh OS X supports TCP/IP
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 will use to communicate • Network Client • Allows the computer system to speak to the protocol • In addition, if you would like share your files or printer, you need to 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 • ISA, PCI • If your 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 • Alt-click My Network Places (or Network Neighborhood) and choose Properties • Double-click the Local Area Connection icon (or choose to Create a New Network Connection) and choose 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
