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Networking Networking Document Transcript

  • Overview • In this part, you will learn to Networking – 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 Networking Technologies • 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 A Few Basics • How will each computer be identified? • A client machine requests information or – If two or more computers want to talk at the same services time, how do you ensure all conversations are • Uses a network interface card (NIC) to understood? define the client on the network and to • What kind of wire should be used to physically make a connection connect the computers together? • A medium to connect the devices is – How many wires in the cable? How thick? How needed long? What type of connectors? – Cable or wireless • How can access to data and peripherals • The operating system needs to be controlled? understand how to network • And the list goes on and on… • A server provides information or services to the client 1
  • Packets, Frames, and MAC Address NICs • Data is broken up into small pieces and • Start Programs Accesories moved about the network in chunks System Tools System Information 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 Packet Fields Protocols • Packets contain the following fields • Protocols are sets of rules – MAC address of the network card that it is being – May be used to define packet types, cabling and sent to connectors, addresses, and much more – MAC address of the network card that sent the • A hardware protocol defines how to get packet data from one computer to another – Data – Ethernet is the dominant standard for today’s – Data check or cyclic networks redundancy check • Coaxial (CRC) used to verify • Unshielded twisted pair the data’s integrity • Fiber optic – Token Ring was developed by IBM but is loosing popularity Thick Ethernet – Coaxial Ethernet 10Base5 • Early Ethernet networks used coaxial • Thick Ethernet cable cable (or just coax) (Thicknet) is used in the 10Base5 – Composed of a center cable surrounded by Ethernet insulation, a shield of braided cable, and an outside specification protective cover – Called RG-8 (Radio – A different type of coaxial cable is used by your Grade) cable VCR and TV – 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 2
  • CSMA/CD CSMA/CD • Carrier Sense Multiple Access/Collision • To prevent collisions when there is Detection (CSMA/CD) is a method used multiple access to a cable, computers by computers to share the same cable first do a carrier sense (listen to the – If two computers talk (try to send data) at the cable for traffic) before trying to send same time, a collision results that corrupts the data data Reflection and CSMA/CD Termination • Even though the computers listen before • Signals traveling along a wire will sending data, it is possible that two bounce back when they get to the end – computers listened at about the same called reflection time, heard nothing, and then sent data • As a result a terminator is installed on – resulting in a collision the ends of the cable to absorb the signal • Computer NICs have collision detection to prevent it from reflecting back – circuitry that alerts them to a collision which would corrupt the signal Connections Thicknet 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 3
  • Thin Ethernet – UTP Ethernet – 10Base2 10BaseT • Thin Ethernet is • Modern networks use UTP Ethernet also known as – Modern networks do not use Thicknet or Thinnet Thinnet – 10BaseT runs at 10 Mbps – Uses RG-58 coax – 100BaseT runs at 100 Mbps cable – 1000BaseT (Gigabit) runs at 1000 Mbps – Limited to 30 devices – Use a star bus topology per segment – Uses unshielded twisted pair (UTP) cabling – 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 Unshielded Twisted Star Bus Topology Pair • Most common topology used is a star bus • UTP is the predominant type of cabling – In a star topology all devices are connected to a used today central device called a hub – Pairs of wires are twisted together in an – Multiple hubs are connected together in a bus unshielded cable topology – UTP cables come in categories (CATs) that define – Together they form a star bus topology the maximum speed at which data can be – Hubs have been replaced by switches that conserve transferred (called bandwidth) bandwidth • CAT5, CAT5e, and CAT6 are most common today Implementing Combo Cards 10*BaseT • Requires at least two pairs of wires – • All Ethernet networks share the same one for receiving and one for sending language • Cables use special RJ-45 connectors • Many NICs will run at either 10 or 100 • The Telecommunications Industry Mbps Assciation/ Electronics Industries • Some NICs have both BNC and RJ-45 Alliance (TIA/EIA) has two standards for ports connecting the RJ-45 connectors – TIA/EIA 568A and TIA/EIA 568B – Use either – just be consistent – Wires are color-coded 4
  • Duplex and Half- Hubs and Switches Duplex • Each PC is connected • Modern NICs can both send and receive to a hub or switch in a 10*BaseT network data at the same time – called full duplex – To add a device, just • Older NICs could send and receive data run another cable to the hub or switch from the but not at the same time – called half device duplex – The maximum • NICs and switches use autosensing to separation between the device and the hub or decide how to operate 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 Fiber Optic Ethernet Token Ring • Fiber optic cable uses light instead of • Developed by IBM electricity • Uses a star ring topology – Immune to electrical interference – Incompatible with Ethernet – Signals can travel up to 2,000 meters – Data travels in a ring – Most Ethernet uses 62.5/125 multimode cable • Uses token passing – Uses two cables – A free token circulates the ring – Uses SC (square-shaped) or ST (round) – A device may send data only connectors when it has the token – Common standards are 10BaseFL and 100BaseFX – Usually reserved for the backbone due to its expense Implementing Token Parallel/Serial Ring Connections • Legacy Token Ring ran • All versions of Windows have software at 4 Mbps or 16 Mbps using IBM Type 1 cable that allows two (and only two) PCs to – Two-pair, shielded twisted connect together via their parallel or pair (STP) cable serial ports – Today’s Token Ring – Use a crossover IEEE 1284 cable for parallel ports networks may use UTP or STP – Use an RS-232 cable for serial ports – 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) 5
  • 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) Network Operating System • 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 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 Domain Controllers • In a peer-to-peer network you must log • Domain Controllers keep the security in to each server you wish to access database of users and passwords • In a domain-based network you log into – Directory services are used to store user names the network just once to access and passwords resources throughout the network • In Windows 2000 and 2003 server, it is called Active – Servers on the network may play one or several Directory roles • In Novell NetWare it is called NetWare Directory Services • Domain Controller (holds the security database) (NDS) • File server • Print server • Fax server • Remote Access Services (RAS) server • Application server • Web server 6
  • Administrative Tools 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 Administrative Tools in Windows XP Professional Administrative Tools in Windows 2000 Server Joining a Workgroup or Domain in Windows 98 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 IPX/SPX • NetBIOS Extended User Interface • Internetwork Packet Exchange/ (NetBEUI) Sequenced Packet Exchange (IPX/SPX) – Small size – Developed by Novell – High speed – Routable – Not routable – NWLink is Microsoft’s version – Limited to small networks 7
  • TCP/IP AppleTalk • Transmission Control Protocol/Internet • AppleTalk is a proprietary protocol Protocol (TCP/IP) developed by Apple – Developed by the U.S. Department of Defense – Used to communicate with older Apple Computers – Used in networks of all sizes – Apple’s Macintosh OS X supports TCP/IP – Used on the Internet Client and Server Software • Client software • Server software – Needed to access data – Any Windows PC may and resources on a be turned into a server network by enabling sharing of – Windows installs Client files, folders, and Installing and Configuring a Wired for Microsoft Networks printers Network Network Connectivity Installing a NIC • To connect to a network you need • When choosing a NIC there are three – Network Interface Card requirements • Physical hardware that connects the PC to the network wire – Must run at the proper speed (many NICs run at – Protocol more than one speed) • The language the devices will use to communicate – Must be for the proper technology – Network Client • Ethernet, Token Ring, Fiber optic (FDDI) • Allows the computer system to speak to the protocol – Must fit into your expansion slot – In addition, if you would like share your files or • ISA, PCI printer, you need to enable Microsoft’s File and • If your NIC does not autoinstall, then Print Sharing use the Add Hardware wizard in Control Panel 8
  • Configuring a Network Client for Microsoft Client Networks • 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 NetBEUI NetBEUI • NetBEUI – Windows 2000: Start Settings Network and Dialup Connections Double-click the Local Area Connection icon – Windows 9x/Me: Start Settings Control Panel double-click the Network applet – Click the Properties button – Install button highlight Protocols and click Add NetBEUI – Windows XP has dropped support for NetBEUI NWLink Configuring TCP/IP • Microsoft’s implementation of IPX/SPX • TCP/IP is the most widely used protocol – You’ll also need to install Client Services for stack in networks today NetWare – It is the protocol of choice for the Internet but may – Install the same way you install NetBEUI but also be used on small private networks choose NWLink instead – TCP/IP is installed just like NetBEUI and NWLink – just choose Internet Protocol (TCP/IP) – You’ll need to configure and IP address and a Subnet Mask at the very least 9
  • IP Addresses Classes of Addresses • Part of an IP address represents the • IP addresses are broken into classes network or subnet (network ID), while based on the size of the network the other part represents the individual – Class A IP addresses are for large companies • The first 8 bits or octet is used to define the network device (host ID) on that given network • The other 3 octets are used to define the hosts or subnet • The first octet begins with 0 • Consists of four sets of 8 binary numbers – Class B IP addresses are for medium size companies (octets) separated by a period • The first two octets define the network – Called dotted-decimal notation • The last two octets define the hosts on each network – Examples are: 10.1.209.5, 202.34.16.11 • The first octet begins with 10 – In binary the second example is: – Class C IP addresses are for smaller companies • The first three octets define the network • 11001010.00100010.00010000.00001011 • The last octet defines the host • The first octet begins with 110 Classes of IP Classes of IP Addresses Addresses • Some addresses are reserved – 127.0.0.1 (the loopback address) is reserved for testing – Three ranges are reserved for private networks • 10.0.0.1 thru 10.255.255.255.254 • 172.16.0.1 thru 172.31.255.254 • 192.168.0.0 thru 192.168.255.254 – One range is reserved for Automatic Private IP Addressing • 169.254.0.1 thru 169.254.255.254 Subnet Mask TCP/IP Services • The subnet mask defines which portion • TCP/IP is an entire suite of protocols of the IP address belongs to the network that offers TCP/IP Services such as ID and which part belongs to the host ID – Hypertext Transfer Protocol (HTTP) used on the – Expressed as a 32-bit number starting with 1s and World Wide Web ending with 0s – Telnet used to access remote systems – 1s represent a network ID bit and 0s represent a – Ping to check communication host ID bit • TCP/IP is used to link multiple networks • For example, 11111111.00000000.00000000.0000000 means that the first 8 bits define the network ID and the (Local Area Networks or LANs) with last 24 bits define the host ID other networks to form an entire Wide – It is associated with an IP address Area Network (WAN) – Routers are used to route traffic among the LANs 10
  • PING, LAN and WAN TCP/IP Settings • IP address • Subnet Mask • Default Gateway – The address of a machine (usually a router) that will deliver messages to hosts outside of your local segment or subnet TCP/IP Settings TCP/IP Settings • Domain Name Service (DNS) • Dynamic Host Configuration Protocol – To reach any host on a TCP/IP network you need (DHCP) to know the IP address – Instead of manually – Instead of remembering IP addresses you may configuring the TCP/IP settings simply remember a user-friendly name on each computer (static settings), you may configure – DNS is a table that equates user-friendly names one computer to manage the to actual IP addresses assignments for you – Computers that handle this use DHCP and are called DHCP servers – On the client computer just choose to “Obtain an IP address automatically” TCP/IP Settings TCP/IP Tools: Ping • Windows Internet Name Service (WINS) • Ping – Enables Windows network names to be correlated – Tests connectivity to a remote host to IP addresses (like DNS does for Internet names) – Define the IP address of the WINS server – Windows 2000/XP uses a dynamic DNS instead of WINS 11
  • TCP/IP Tools: TCP/IP Tools: ipconfig WINIPCFG • WINIPCFG • IPCONFIG – Displays your TCP/IP settings in Windows 9x/Me – Displays your TCP/IP settings in Windows – Release and Renew allows you to get new TCP/IP NT/2000/XP information from a DHCP server – Release and Renew allows you to get new TCP/IP information from a DHCP server TCP/IP Tools: TCP/IP Tools: tracert nslookup • NSLOOKUP • TRACERT – Determines the name of a DNS server among other – Shows the route a packet takes to its destination things • Type exit to return to the command prompt Sharing Drives and TCP/IP Tools: APIPA Folders • Automatic Private IP Addressing (APIPA) • To share a drive or folder, alt-click it and – When a client cannot obtain an IP address select Sharing automatically, Windows 2000/XP will automatically – Share name is the name others will see on the assign its own IP address from the range network 169.254.0.0 thru 169.254.255.254 with a subnet – Windows 9x/Me allows you to define what a user mask of 255.255.0.0 may do: Read Only, Full, or Depends on Password – APIPA is of value when a DHCP server is not – Windows NT/2000/XP using NTFS-formatted drives available – it allows the hosts on the LAN to talk to allows for much greater and precise control each other even though they can’t reach anyone • Set the network (Sharing tab) permissions to Full Control outside their LAN • Then use NTFS permissions (Security tab) to exercise more precise control over who accesses the shared resource and how they access them 12
  • Sharing Drives and Accessing Shared Folders Resources • Access shared drives or folders using Network Neighborhood (Windows NT and 9x) or My Network Places (Windows Me, 2000, XP) – You may also map a drive letter to a shared drive or folder – Windows 2000 allows you to add a network icon instead of using a drive letter – Windows XP adds a menu option UNC Sharing Printers • Universal Naming Convention (UNC) • To share a printer, just alt-click on the allows you to access network resources printer and choose Sharing as follows • To access the printer, use the Add Printer icon and select Network printer SERVER1FREDC instead of Local printer Computer name Share name Introduction • Wireless networks are growing in popularity • Instead of cables, wireless networks use Installing and Configuring a either radio waves or beams of infrared Wireless Network light to communicate with each other • Most of today’s wireless networks are based on the IEEE 802.11 standard – Home Radio Frequency – Wi-Fi – Those based on Bluetooth technology 13
  • Wireless Networking Infrared Connections Components • Infrared transceiver ports are standard • Connection components on many portable computer, PDAs, and for wider access high-end printers – PCI cards that accept wireless – Used to connect local devices to each other without PC cards using a cable – External USB wireless NICs Wireless Networking Wireless Access Point Software • Wireless Access Point (WAP) • Wireless devices use the same – Acts like a hub to the wireless hosts in the area networking clients and protocol as wired networks – Use CSMA/CA but have difficulty detecting data collisions • Another option is using Request to Send/Clear to Send (RTS/CTS) where the sending node issues an RTS to the receiving node, who replies with a CTS • Wireless networking software is PnP – Use a utility (usually provided with the wireless NIC or built into Windows) to configure the Service Set Identifier (SSID), or network name Wireless Configuration Wireless Network Utility Modes • Ad hoc Mode – Each wireless node is in direct contact with each other in a decentralized free-for-all – Form an Independent Basic Service Set (IBSS) – Called peer-to-peer mode – Good for a few computers or temporary network 14
  • Wireless Network Wireless Networking Modes Security • Infrastructure Mode • Service Set Identifier (SSID) – Use one or more WAPs – Configure a unique SSID or network name to connect wireless nodes to a wired – Each node needs to have the same SSID network segment – Not very secure but better than nothing – A single WAP is called a • MAC Filtering Basic Service Set (BSS) – Filtering based on each host’s MAC address burned – Additional WAPs create into their NIC an Extended Basic Service Set (EBSS) – Creates a type of accepted user Wireless Network Wireless Networking Security Standards • Wireless Equivalency Privacy (WEP) • IEEE 802.11-Based Wireless Networking – Encrypts data using 40-bit or 104-bit encryption – Wireless Ethernet standard using spread-spectrum – Provides authentication based on MAC addresses radio waves but not users – Broadcast and receive at 2.4 GHz – Encrypts only OSI layers 1 and 2 • 802.11a uses 5 GHz • Wi-Fi Protected Access (WPA) – The original standard has been extended to form the Shared Wireless Access Protocol (SWAP) used – User authentication using the Extensible in HomeRF networks Authentication Protocol (EAP) – Uses encryption key integrity-checking • IEEE 802.11i – New security standard Wireless Network 802.11 Standards Standards • Infrared Wireless Networking – Simple way to share data without adding any additional hardware or software – Uses the Infrared Data Association (IrDA) protocol • Included in Windows 95 and higher – Line-of-sight required – No authentication or encryption • But then you can’t be over 1 meter away 15
  • Configuring Wireless Configuring Wireless Networks Networks • Physically installing a wireless NIC is the • Wi-Fi and HomeRF same as installing a wired NIC – Ad hoc • Each wireless node needs to be configured with the same • Install the wireless network network name (SSID) configuration utility to configure • May need to select a common channel additional parameters • Configure unique host IP addresses – Windows XP has configuration parameters built-in • Configure File and Printer Sharing • The more important issue is – Infrastructure modes • Requires a wireless access point (WAP) authentication and security • All nodes need to be configured with the same SSID • Configure the WAP with clients that match the chosen options Configuring Wireless Configuring Wireless Networks Networks • Configuring a Wireless Access Point (WAP) is usually done through a web browser – Enter the WAP’s default IP address (see your documentation or try 192.168.1.1) in your browser – Enter the default administrative password (in your documentation) to log in • The next few slides show some screen shots of the configuration pages Configuring Wireless Configuring Wireless Networks Networks 16
  • Configuring Wireless Configuring Wireless Networks Networks • Encryption screen on client wireless network adapter configuration utility Configuring Wireless Networks • Infrared – About the only thing to do is to confirm in your network protocol configuration screen that you have the IrDA protocol installed and enabled – To transfer files just alt-click the file in Windows Connecting to the Internet Explorer and choose Send To Infrared Recipient – To network two computers just choose Connect Directly to Another Computer when choosing the connection type Dial-up Requires a Ways of Connecting Modem • Dial-up • The term modem is an abbreviation for – Analog modulator/demodulator – ISDN – Enables computers to communicate with each other via standard telephone lines • Dedicated – Convert analog signals into digital signals that can – DSL be understood by the PC’s COM ports – Cable – Convert digital signals from the PC’s COM ports into analog signals for standard telephone lines – LAN – Transmit data as a series of • Wireless individual 1’s and 0’s… • Satellite serial communication 17
  • Modem Connections Dial-up Networking • Modems connect to the PC in one of two • Dial-up networking ways – Uses information from your ISP such as the dial-up – Internal modems connect to a PCI expansion slot phone number, username, password, and other – External modems connect thru a serial port or a special configuration parameters USB port – To configure in Windows XP select Network and Internet Connections in Control Panel, then select Set up or change your Internet connection and follow the wizard – Uses Point-to-Point Protocol (PPP) ISDN DSL • Integrated Services Digital Network • Digital Subscriber Line (DSL) (ISDN) – Uses a regular phone line – Phone companies have upgraded their network – Needs special equipment at both ends infrastructure to all digital lines – except for the – Much faster than dial-up: line from your phone to the central office • Upload: 384 Kbps – To meet the demand for higher speed access to the • Download: 2 Mbps Internet, phone companies began offering ISDN – Installation requires a NIC and DSL receiver (called service a DSL modem) and • ISDN makes that last mile from your phone to the phone proper TCP/IP settings company’s Central Office digital as well – Must be within 18,0000 feet from the closest frame Other Internet Cable Connections • Cable • LANs – Uses cable TV connections – Most companies connect their network to the – Very fast speeds…as fast as DSL or faster Internet thru an ISP – Installation involves connecting the RG-6 or RG-59 – Users connect thru the local LAN coaxial cable coming in for cable TV to a cable • Wireless modem to a NIC in the PC – Wireless connections are great when they work, – Bandwidth is shared with other users which could but the technology isn’t quite there yet affect performance – Security may be an issue • Satellite – Uploads used to require a modem but not anymore – Initial connections still must be made thru a modem 18
  • Troubleshooting Networks 1. Verify the symptom – Talk with the user to try to get a solid description of the symptoms Troubleshooting Networks 2. When did it happen? – Does it happen at boot, when the OS loads, or after the system has been running for awhile? 3. What has changed? – Try to find out if anything has changed – even recent changes before the problem began occurring Troubleshooting Troubleshooting Networks Networks 4. Check the environment 7. Separate hardware from software – Heat, humidity, dirt – Replace the suspect hardware with known good – What OS? What applications? Do others use the hardware – if that doesn’t solve the problem, then computer? it’s probably software related 5. Reproduce the problem – Uninstall the suspect software and reinstall it – Install the latest patch or upgrade – If a problem happens only once, it’s not a problem – Check for viruses – Otherwise, try to make the problem happen again 6. Isolate the symptom 8. Research – Use the Internet as a great tool – With hardware remove parts until you find the suspect one 9. Make the fix and test – With software remove background programs or – Keep track of what you did so that you may return boot into Safe Mode to the previous state if the fix does not work Mike’s Four-Layer Bluetooth Model • Hardware • Bluetooth is designed to replace all those – Check the hardware starting with the physical layer cables connecting peripheral devices • Protocols together – keyboards, mouse, printer, – Is it installed and configured properly? speakers, scanner – Acceptable for quick file transfers • Network – Acceptable for browsing the Internet – Servers and non-servers – Hardware comes integrated on most new portable – Check users and groups, share names electronic devices or as an internal or external • Shared resources adapter – Make sure the resource has been properly shared – Configuration is PnP – Check the access allowed – Bluetooth access points use a web browser for configuration 19