Networking

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Networking

  1. 1. 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
  2. 2. 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
  3. 3. 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
  4. 4. 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
  5. 5. 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
  6. 6. 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
  7. 7. 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
  8. 8. 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
  9. 9. 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
  10. 10. 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
  11. 11. 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
  12. 12. 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
  13. 13. 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
  14. 14. 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
  15. 15. 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
  16. 16. 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
  17. 17. 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
  18. 18. 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
  19. 19. 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

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