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Chapter 21

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  • Discussion Point Networking This chapter is long and includes complicated topics, even though it covers only some networking concepts. There are entire courses designed around networking technologies, such as CompTIA’s Network+. There are advanced certifications such as the Microsoft Certified System Engineer (MCSE) and Certified Novell Engineer (CNE) courses. There are even entire courses for single networking topics such as TCP/IP. This chapter will only familiarize the students with the networking concepts and help them set up simple networks, as per the requirements of the CompTIA A+ certification.
  • Even though MAC addresses are embedded into the NIC, some NICs will allow you to change the MAC address on the NIC. This is rarely done.
  • You’ve most likely seen coaxial cable before, although perhaps not in a networking situation. Your cable TV and antenna cables are coaxial, usually RG-59 or the highly shielded RG-6. Watch out for questions on the exams dealing specifically with networking hardware protocols trying to trip you up with television-grade coaxial answers!
  • Tech Tip PVC vs. Plenum Most workplace installations of network cable go up above the ceiling and then drop down through the walls to present a nice port in the wall. The only potential problem with cabling running through the walls and ceiling is that the protective sheathing for networking cables is made from plastic, and if you get any plastic hot enough, it will create smoke and noxious fumes. To reduce the risk caused by burning buildings, all cables have fire ratings. The two most common fire ratings are PVC and Plenum. PVC (Poly-Vinyl Chloride) has no significant fire protection. If you burn a PVC cable, it creates lots of smoke and noxious fumes. Burning Plenum cable creates much less smoke and fumes, but Plenum costs about three to five times as much as PVC. Most city ordinances require the use of Plenum-rated cable for network installations. Bottom line? Get Plenum!
  • Discussion Point Building Cables When building network cables, it is important to follow the 568 standards all the time. Even though 10BaseT uses only two pairs of cables (you can actually omit the other two pair), it is good practice to build the cable the right way all the time. Doing this is useful for two reasons: first, you will always be in the habit of making the cables the right way; and second, if the network upgrades to 100BaseT, you will not have to rebuild all those cables. Discussion Point Crossover Cables If you want to connect two computers, but do not have a hub, you can connect them directly with a crossover cable. The crossover cable “crosses over” the transmission and receiving wires to enable two computers to be directly connected. The crossover cable will work only if connected to two NIC cards directly, and it will not work if connected to a hub. A normal cable will not work when connecting two computers directly. You can purchase a crossover cable, or you can build one. Exercise Building Cables It is now time to build some cables. Ask the students to measure the distances from the hub to each device (PCs and printers). You can show a PowerPoint slide detailing the RJ-45 wiring diagrams as a reference for the duration of this exercise. Have the students make a few crossover cables first. Check each cable end for correct wiring. Ask the students to build at least enough cables to connect all the PCs (if you have ten PCs, you will need five crossover cables). To save resources, you can cut the crossover end off to build a normal cable after you do the first part of the installation exercise (peer-to-peer crossover network). Ask the students to build a few UTP cables using RJ-45 jacks. Check each cable end for correct wiring.
  • Tech Tip Crossover Cables You can actually hook two 10xBaseT network cards together without a hub by using a special UTP cable called a crossover cable. A crossover cable is a standard UTP cable, but it has one RJ-45 connector using the 568A standard and the other using the 568B standard. This reverses the signal between sending and receiving wires and thus does the job of a hub or switch. Crossover cables work great as a quick way to network two PCs. You can purchase a crossover cable at any computer store.
  • Tech Tip Multimode and Single Mode Light can be sent down a fiber optic cable as regular light or as laser light. Each type of light requires totally different fiber optic cables. Most network technologies that use fiber optics use LED, or Light Emitting Diodes, to send light signals. These LEDs use multimode fiber optic cabling. Multimode fiber optic transmits multiple light signals at the same time, each using a different reflection angle within the core of the cable. The multiple reflection angles tend to disperse over long distances, so multimode fiber optic cables are used for relatively short distances. Network technologies that use laser light use single-mode fiber optic cabling. Using laser light and single-mode fiber optic cables allows for phenomenally high transfer rates over incredibly long distances. Single-mode fiber optic cabling is currently quite rare; if you see fiber optic cabling, you can be relatively sure that it is multimode.
  • Tech Tip Modern Token Ring Networks Token Ring manufacturers have not rolled over and given in to the pressure of Ethernet standards, but rather have continued to adapt and innovate. Modern IEEE 802.5t Token Ring networks run at 100 Mbps or faster, and because the ring technology does not suffer from the overhead of CSMA/CD, you get phenomenally faster performance from High Speed Token Ring (HSTR) networks than from comparably speedy Ethernet. Check them out here: www.token-ring.com.
  • The terms “client” and “server” are, to say the least, freely used in the Windows world. Keep in mind that a client generally refers to any process (or in this context, computer system) that can request a resource or service, and a server is any process (or system) that can fulfill the request.
  • Discussion Point Administrator All NOSs have a special account called Administrator. Some NOSs may have a different name for that account, such as Root, but they all have one thing in common: they have access to anything and everything on the network. These super accounts control the entire network. Anyone who has access to this account can bring down an entire network. If you have an account with this privilege, you must not disclose the password to others. If you forget the password, you will need to completely reinstall the NOS.
  • A node is any device that has a network connection—usually this means a PC, but other devices can be nodes. For example, many printers now connect directly to a network and can, therefore, be termed nodes. I use the term node extensively in the rest of the chapter in place of PC or networked computer. This is especially true when I discuss wireless technologies, because that’s the term the manufacturers use.
  • If you have the option, you should save yourself potential headaches and troubleshooting woes by acquiring new, name-brand NICs for your Windows installation.
  • Exercise Installing the NIC Cards Now you can ask the students to install the NIC cards. Make sure they are installed and configured properly. If they are legacy cards, the students will need to set the resources manually, including the IRQ, I/O, and DMA. Depending on the card, they may have to set the jumpers, or they may need to boot to the Safe Mode command prompt (otherwise Windows may interfere with the installation) and install the Setup program on the accompanying installation disks to configure the resources. The students then reboot to Windows and install the NIC drivers. If they are PnP, installation should be easy. Verify the card is working in the Device Manager. Students benefit from installing PnP and legacy cards for orientation and experience.
  • Client Service for NetWare does not support the IP protocol used in NetWare 5. x .
  • When NWLink is set to autodetect the frame type, it will only detect one type, searching in the following order: (1) 802.2, (2) 802.3, and (3) 802.5.
  • The A+ Certification exams do not require you to configure IP addresses and subnet masks, but you should know what they are and how to find them on a PC.
  • Instructor Tip Use a chalkboard or whiteboard to demonstrate octets. It will be much easier for the students to pick up the concept this way. Discussion Point Octets The root of the word “octet” is “oct” meaning eight. Why is a three-digit number called an octet? Because each octet is a representation of an 8-bit binary number consisting of 1s or 0s. Starting from the right, the first digit has a value of 1, the next digit to the left has a value of 2, the next digit has a value of 4, and so on. Each number is double the previous one. You merely add the values of the digits together for the octet number. Value: 128 64 32 16 8 4 2 1 Binary: 0 1 0 0 1 1 1 0 Now add the value of each 1: 2 + 4 + 8 + 64 = 78 So, 01001110 equals 78. By converting each octet (1s and 0s) to its decimal form, you get a recognizable IP number such as 207.46.230.229. By adding the values of the 1s and 0s, you can quickly see that if you have all 1s, you have 255 (128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255) and if you have all 0s, you have 0.
  • Primary and Secondary DNS The primary DNS server is the first computer used to resolve Internet addresses to IP addresses. A backup computer is called the secondary DNS server. Internet Corporation for Assigned Names and Numbers (ICANN) If you want a domain name that others can access on the Internet, you must register your domain name and pay a small annual fee. Your Internet Service Provider (ISP) can probably handle this for you. These names are assigned by ICANN.
  • Use this optional slide to show that name resolution is handled in several different ways, but focus here is only on the DNS server and the WINS server.
  • Where are the TCP/IP settings? Windows 9 x /Me using modems: My Computer  Dial-up Networking icon  right-click the connection and select Properties  Server Type  TCP/IP Settings Windows 9 x /Me with a direct connection: Control Panel  Networks  TCP/IP  Properties Windows 2000/XP: Right-click My Network Places and choose Properties  right-click the connection and choose Properties  double-click Internet Protocol (TCP/IP)  and click the Advanced button for additional settings
  • Discussion Point Ping It is widely believed that Ping (an important network utility) is an acronym for Packet Internet Groper. This is not so. According to the author of Ping, Mike Muuss (who died in a car crash on November 21, 2000), he wrote the Ping program in 1983 to help track down a network disconnect. The computer he was working on would send out a small packet, and when it reached the destination, it would bounce back. He named it Ping because it reminded him of the ping sound of a submarine’s sonar. (Source: http:// ftp.arl.mil/~mike/ping.html )
  • Make sure you know that Windows 9 x /Me uses WINIPCFG and Windows NT/2000/XP uses IPCONFIG.
  • You can do cool stuff with NSLOOKUP; some techs absolutely love the tool. It’s way outside the scope of A+ Certification, but if you want to play with it, type help at the NSLOOKUP prompt and press ENTER to see a list of common commands and syntax.
  • Each line indicates a router
  • Discussion Point Share Names Simply naming a shared drive with C is usually not a good idea because a network user could confuse your C with someone else’s C. It is best to give the drive a unique name. You can name it for the person using that computer all the time (Dave), by content (MP3s), the desk position (Desk4), or anything else you want, so long as it is easy for network users to figure out what drive it is.
  • Windows NT/2000/XP has two types of sharing: Network permissions and NTFS permissions. Windows 9 x /Me has only Network permissions.
  • All shared resources should show up in Network Neighborhood/My Network Places. If a shared resource fails to show up, check the basics first: Is File and Print Sharing activated? Is the device shared? Don’t let silly errors fool you!
  • The A+ Core Hardware Exam loves questions on cables and connectors, so look for questions on USB adapters and WAPs.
  • Changing the default SSID for a WAP is the first step in securing a wireless network.
  • HomeRF HomeRF, as the name implies, is intended for home use, not for use in large business network environments. It is easy to set up and maintain but doesn’t offer much in the way of range (about 150 feet, maximum). Early HomeRF devices were fairly slow, clocking in at a maximum of 2 Mbps, but the later version 2.0 operates at a respectable 10 Mbps and also provides full backward-compatibility with the earlier HomeRF technology. HomeRF wireless networks use the SWAP protocol, a hybrid of the Digital Enhanced Cordless Telecommunications (DECT) standard for voice communication and the 802.11 wireless Ethernet standard for data. HomeRF uses seven channels in the 2.4-GHz range, six of which are dedicated to voice communication with the remaining one used for data. Because HomeRF devices use the FHSS spread-spectrum broadcasting method, they are less prone to interference and somewhat more secure than Wi-Fi devices. HomeRF uses a proprietary 56-bit (128-bit in version 2.0) encryption algorithm instead of the industry-standard WEP and WPA that 802.11 uses. Also, instead of an SSID name, HomeRF uses what is called a network ID (NWID), which is somewhat more secure.
  • Tech Tip Increasing Wireless Range Range can be increased in a couple of ways. First, you can install multiple WAPs to permit “roaming” between one WAP’s coverage area and another’s—an EBSS, as described earlier in this chapter. Second, you can install a signal booster that increases a single WAP’s signal strength, thus increasing its range.
  • Look for basic troubleshooting questions on the A+ Certification exams dealing with factors that affect wireless connectivity, range, and speed.
  • Exercise Troubleshooting the Network As with all other troubleshooting exercises, your goal here is to set up a “service call” for the students. You want them to go into diagnostics mode to figure out what the problems might be. In networking, you have tons of places to change settings surreptitiously, disconnect cables, use known bad cables, or use a crossover cable with a hub or a normal cable when directly connecting two computers. Alter TCP/IP settings, unplug the hub, and so on, to disable the network or network connection.
  • Transcript

    • 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 network connect to a central wiring point (often a switch or a hub)
      • Mesh topology
        • Each computer has a dedicated line to every other computer
    • 8. Getting the Right Sound Card CompTIA A+ Essentials Essentials 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 VCR and 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 connected one 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… Some of the signal is reflected back When an electrical signal reaches the end of a terminated wire… 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 (10 x BaseT)
        • 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
      CAT 1 Standard phone line CAT 2 ISDN & T1 lines Speeds up to 4 Mbps CAT 3 Speeds up to 16 Mbps CAT 4 Speeds up to 20 Mbps CAT 5 Speeds up to 100 Mbps CAT 5e Speeds up to 1 Gbps CAT 6 Speeds up to 10 Gbps
    • 23. Implementing 10 x BaseT
      • 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.
      • Ethernet networks share same language
      • Many NICs run at 10 or 100 Mbps
      • Some NICs have BNC and RJ-45 ports
      • Most NICs built into motherboards are autosensing
        • Run at speed of network
      Combo Cards
    • 25. Hubs and Switches
      • Each PC is connected to a hub or switch in a 10 x BaseT 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 and Server Software
      • 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
    • 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
    • 51. IP Addressing
      • IP addresses are unique on a network
      • Expressed in dotted-decimal notation
        • 202.34.16.11
      • Composed of 32 bits in four octets
        • 202 expressed as 1 1 0 0 1 0 1 0
        • 34 expressed as 0 0 1 0 0 0 1 0
        • 16 expressed as 0 0 0 0 1 0 0 0
        • 11 expressed as 0 0 0 0 1 0 1 1
    • 52. IP Addressing
      • IP addresses are broken into classes based on the size of the network
        • First number in dotted-decimal format determines class
          • 15.16.17.18 15 is Class A
          • 192.7.8.9 192 is Class C
        • First number also determines subnet mask
      Class Address Range Subnet Mask Class A 1–126 255.0.0.0 Class B 128–191 255.255.0.0 Class C 192–223 255.255.255.0
    • 53. Classes of IP 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
    • 54. Subnet Mask
      • The subnet mask defines which portion of the IP address belongs to the network ID and which part belongs to the host ID
        • Expressed as dotted-decimal format as 32-bit number starting with 1s and ending with 0s
        • 1s represent a network-ID bit and 0s represent a host-ID bit
          • For example, 11111111.00000000.00000000.0000000 means that the first 8 bits define the network ID and the last 24 bits define the host ID
        • The subnet mask is associated with an IP address
    • 55. IP Addresses
      • Two parts of an IP address
        • Network ID represents the network or subnet
        • Host ID represents the individual device
      • You determine which is which with the subnet mask
        • When the subnet mask is maximum, that portion of the IP address is the network ID
        • 192.168.1. 15 10 .15.16.17 IP address
        • 255.255.255 .0 255 .0.0.0 Subnet Mask
        • 192.168.1 .0 10 .0.0.0 Network ID
    • 56. TCP/IP Services
      • TCP/IP is an entire suite of protocols that offers TCP/IP services such as
        • Hypertext Transfer Protocol ( HTTP ) used on the World Wide Web
        • Telnet used to access remote systems
        • Ping to check communication
      • TCP/IP is used to link multiple networks ( local area networks or LAN s) with other networks
        • Forms a wide area network ( WAN )
        • Routers are used to route traffic among the LANs
    • 57. Typical LAN
      • Shows two networks or subnets
        • Router is path to other network
          • This router has two NICs (one on each network)
          • Data sent from CPU1 to CPU2 goes through Default Gateway (different subnet)
      Router Subnet 2 Network ID 192.168. 15 .0 255.255.255.0 Subnet 1 Network ID 192.168. 1 .0 255.255.255.0 Default gateway Default gateway CPU1 CPU2
    • 58. TCP/IP Settings
      • Domain name service ( DNS )
        • To reach any host on a TCP/IP network, you need to know the IP address
        • Instead of remembering IP addresses, you most likely simply remember a user-friendly name
        • DNS resolves user-friendly names to actual IP addresses (name resolution)
    • 59. Name Resolution
      • Two types of names
        • Internet (host) and Windows (NetBIOS)
      • Seven types of name resolution
        • Focus here only on DNS and WINS
      Name Type Static Dynamic Cache Host Internet name HOSTS file DNS server Hosts cache View with IPConfig /DisplayDNS NetBIOS Windows name LMHosts file WINS server NetBIOS cache View with NBTSTAT –C Broadcast
    • 60. TCP/IP Settings
      • Windows Internet Name Service ( WINS )
        • Enables Windows network names to be resolved to IP addresses (like DNS does for Internet names)
        • When configuring a NIC, you would define the IP address of the WINS server
        • WINS is being used less and less
    • 61. 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
    • 62. TCP/IP Settings: DHCP
      • Dynamic host configuration protocol
        • Can manually configure TCP/IP settings
        • Can configure to get TCP/IP settings automatically (from DHCP)
        • Requires DHCP server
        • On the client computer, simply choose Obtain an IP address Automatically
    • 63. TCP/IP Tools: Ping
      • Ping
        • Tests connectivity to a remote host
        • Many options use ping /? for help
    • 64. TCP/IP Tools: IPCONFIG
      • IPCONFIG
        • Displays your TCP/IP settings in Windows NT/2000/XP
        • Release and Renew allows you to get new TCP/IP information from a DHCP server
    • 65. TCP/IP Tools: NSLOOKUP
      • NSLOOKUP
        • Determines the name of a DNS server among other things
          • Type exit to return to the command prompt
    • 66. TCP/IP Tools: TRACERT
      • TRACERT
        • Shows the route a packet takes to its destination
    • 67. TCP/IP Tools: APIPA
      • Automatic Private IP Addressing ( APIPA )
        • If set to get addresses from DHCP but DHCP server cannot be reached, APIPA address is assigned
          • Automatically assigns an IP address in range 169.254.0.0 thru 169.254.255.254 with a subnet mask of 255.255.0.0
          • No routing capabilities
      Router CPU1 DHCP DHCP can’t be reached APIPA address assigned
    • 68. Sharing Drives and Folders
      • To share a drive or folder, right-click it and select Sharing
        • Share name is the name others will see on the network
        • Windows 2000/XP uses NTFS-formatted drives
          • Allows for much greater and precise control
          • Set the network (Sharing tab) permissions to Full Control
          • Then use NTFS permissions (Security tab) to exercise more precise control over who accesses the shared resource and how they access them
    • 69. Sharing Drives and Folders
      • Share Permissions
        • Full Control
        • Change
        • Read
        • NTFS Permissions allow more control
    • 70. Accessing Shared Resources
      • Access shared drives or folders using My Network Places (Windows 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
    • 71. UNC
      • Universal Naming Convention (UNC)
        • Allows you to access network resources as follows
        • Can enter directly from Run line to access UNC path
      ERVER1FREDC Computer name Share name
    • 72. Sharing Printers
      • To share a printer, just right-click on the printer and choose Sharing
      • To access the printer
        • Use the Add Printer icon
        • Select Network Printer instead of Local Printer
    • 73. Getting the Right Sound Card CompTIA A+ Essentials Essentials Installing and Configuring a Wireless Network
    • 74. Introduction
      • Wireless networks are growing in popularity
      • Wireless networks use radio waves or beams of infrared light to communicate with each other
      • Two primary types of wireless networks
        • Based on IEEE 802.11 standard
        • Based on Bluetooth technology
    • 75. Wireless Networking Components
      • Many capabilities built-in today
        • Infrared ports standard in laptops, PDAs, and high-end printers
        • Infrared not usually included in desktop PCs
    • 76. Wireless Networking Components
      • Wireless Ethernet and Bluetooth often integrated or can easily be added
        • USB, PCI, PCI Express, or PC Card adapters
    • 77. Wireless Networking Components
      • Wireless access point ( WAP )
        • Acts like a hub to the wireless hosts in the area
      • Bluetooth
        • Built-in option on many newer PCs
    • 78. IT Technician CompTIA A+ Technician Wireless Networking Software
    • 79. Wireless Networking Software
      • Wireless devices use same networking clients and protocol as wired networks
        • Use CSMA/CA (CA stands for collision avoidance)
          • Another option is using Request to Send/Clear to Send (RTS/CTS)
          • Sending node issues an RTS to the receiving node as a request
          • Receiving node replies with a CTS when it’s clear
          • Once data is received, receiving node sends an ACK (acknowledge)
    • 80. Wireless Configuration Utility
      • Wireless networking software is PnP
        • Use a utility to configure parameters
          • Windows built-in utility or vendor provided
          • Configure the Service Set Identifier ( SSID ) here
    • 81. Wireless Networking Modes
      • Ad-hoc mode
        • Each wireless node is in direct contact with every other node 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 such as study groups or business meetings
    • 82. Wireless Networking Modes
      • Infrastructure Mode
        • Use one or more WAPs to connect wireless nodes to a wired network segment
        • A single WAP is called a Basic Service Set ( BSS )
        • Additional WAPs create an Extended Basic Service Set ( EBSS )
    • 83. Wireless Networking Security
      • Three methods used to enhance security
      • Service Set Identifier ( SSID )
        • Configure a unique SSID or network name
          • Default is often name of vendor such as “LinkSys”
          • Widely known so easy to guess
        • Each node needs to have the same SSID
        • Turn off SSID broadcasting
      • MAC filtering
        • Filtering based on each host’s MAC address
        • Creates a type of accepted user
        • Included in each packet, so can be discovered and impersonated
    • 84. Wireless Networking Security
      • Wireless Equivalency Privacy ( WEP )
        • Encrypts data using 40-bit or 104-bit encryption
        • Provides authentication based on MAC addresses
        • Significant flaws
      • Wi-Fi Protected Access ( WPA )
        • Interim upgrade to WEP
        • Uses encryption key integrity-checking
      • WPA2 (IEEE 802.11i )
        • Full upgrade to WEP
        • Significant improvements
        • Current wireless security standard
    • 85. Speed and Range Issues
      • Wireless speeds range from 2 Mbps to 54 Mbps
      • Speed affected by range
        • Speed dynamically negotiated
        • Maximum throughput at approximately 25 feet
        • At edge of range, throughput may decrease to 1 Mbps
        • Range not exact
          • Often listed as around 150 feet or 300 feet
    • 86. Wireless Networking Standards
      • 802.11-based wireless networking
        • Three primary standards
        • All can work in ad-hoc or infrastructure modes
      802.11a 802.11b 802.11g Max throughput 54 Mbps 11 Mbps 54 Mbps Max range 150 feet 300 feet 300 feet Frequency 5 GHz 2.4 Ghz 2.4 Ghz Security SSID, MAC, WEP, WPA SSID, MAC, WEP, WPA SSID, MAC, WEP, WPA Compatibility 802.11a 802.11b 802.11b, 802.11g
    • 87. Wireless Networking Standards
      • Infrared wireless networking
        • Simple way to share data without adding any additional hardware or software
        • Uses the Infrared Data Association (IrDA) protocol
        • Line-of-sight required
        • No authentication or encryption
          • You can’t be more than 1 meter away
      Infrared (IrDA) Max throughput Up to 4 Mbps Max range 1 meter (39 inches) Security None Compatibility IrDA Communication mode Point-to-point ad-hoc
    • 88. Wireless Networking Standards
      • Bluetooth
        • Designed to create small wireless personal area networks (PANs)
        • Typically used for peripherals
          • Mice, keyboards, PDAs, etc.
      Bluetooth High-powered Bluetooth Max throughput 1 Mbps 2 Mbps Max range 10 meters 300 feet Compatibility Bluetooth Bluetooth Communication mode PAN PAN
    • 89. Wireless Networking Standards
      • Cellular
        • Many PDAs and phones today allow connection to Internet
        • Downloads as quick as 400 to 700 Kbps
        • Cellular networks have their own protocols
        • Downside is the price
    • 90. Configuring Wireless Networks
      • Physically installing a wireless NIC is the same as installing a wired NIC
      • Wireless network configuration utility
        • Used to configure additional parameters
        • Configure SSID and encryption
        • Configure communication mode
          • Ad-hoc
          • Infrastructure
    • 91. Configuring Wireless Networks
      • Wi-Fi
        • Ad hoc
          • Each wireless node needs to be configured with the same network name (SSID)
          • May need to select a common channel
          • Configure unique host IP addresses
          • Configure File and Printer Sharing
        • Infrastructure modes
          • Requires a wireless access point (WAP)
          • All nodes need to be configured with the same SSID
          • Configure the WAP with clients that match the chosen options
    • 92. Configuring Wireless Networks
        • NETGEAR wireless configuration utility
    • 93. Configuring Wireless Networks
      • Configuring a wireless access point is often 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 screenshots of the configuration pages
    • 94. Configuring Wireless Networks
      • Sample home page
    • 95. Configuring Wireless Networks
      • Configuring MAC address filtering
    • 96. Configuring Wireless Networks
      • Configuring encryption
    • 97. Configuring Wireless Networks
      • Infrared
        • Not much to configure
        • Confirm the IrDA protocol is installed
        • To transfer files
          • Use Wireless Link applet
          • Use Windows Explorer
        • To network two computers
          • Choose Connect Directly to Another Computer
    • 98. Configuring Wireless Networks
      • Bluetooth
        • Completely plug and play
          • May need to use vendor-supplied drivers
        • Bluetooth devices seek each other out
          • Establish a master/slave relationship
        • PANs sometimes have specialized software utility
    • 99. Troubleshooting Networks
    • 100. Troubleshooting Networks
      • Networked and non-networked situations differ drastically
        • Networked situations add complexity
      Router or switch CPU1 Print server If a user can’t print from CPU1, it could be due to many possible problems on the network. Networked printer X X X X X X X
    • 101. Troubleshooting Networks
      • Verify the symptom
        • Talk with the user to try to get a precise description of the symptoms
      • When did it happen?
        • Does it happen during boot, when the OS loads, or after the system has been running for a while?
      • What has changed?
        • Try to find out if anything has changed
        • Even recent changes before the problem began occurring
    • 102. Troubleshooting Networks
      • Check the environment
        • Heat, humidity, dirt
        • What OS? What applications? Do others use the computer?
      • Reproduce the problem
        • If a problem happens only once, it’s not a problem
        • Otherwise, try to make the problem happen again
      • Isolate the symptom
        • Hardware—remove suspect parts
        • Software—remove background programs or boot into Safe Mode
    • 103. Troubleshooting Networks
      • Separate hardware from software
        • Replace the suspect hardware with known good hardware
        • Uninstall the suspect software and reinstall it
        • Install the latest patch or upgrade
        • Check for viruses
      • Research
        • Use search engines on the Internet
      • Make the fix and test
        • Keep track of what you did so you may return to the previous state if the fix does not work
    • 104. OSI Seven-Layer Model
      • Use as a guide in troubleshooting
      Layer Number Name Description Layer 1: Please Physical NICs (link light), cables, switches, hubs, etc. 1s, 0s Layer 2: Do Data Link MAC addresses and CSMA/CD Layer 3: Not Network IP operates here Layer 4: Throw the Transport TCP/UDP operate here Layer 5: Sausage Session Manages connections Layer 6: Pizza Presentation Describes how to present data Layer 7: Away Application Interacts with user
    • 105. Mike’s Four-Layer Model
      • Hardware
        • Check the hardware starting with the physical layer
      • Protocols
        • Is it installed and configured properly?
      • Network
        • Servers and nonservers
        • Check users and groups and share names
      • Shared resources
        • Make sure the resource has been properly shared
        • Check the access allowed
    • 106.