Local Area Networking Chapter 21

Transcription

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 Essentials CompTIA A+ Essentials Getting the Right Sound Card 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 When an electrical signal reaches the end of a wire When an electrical signal reaches the end of a terminated wire Some of the signal is reflected back There is no reflection A terminator absorbs the 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 8 1

24 Combo Cards 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

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/Vista/7 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 Composed of 32 bits in four octets 202 expressed as expressed as expressed as expressed as

52 IP Addressing IP addresses are broken into classes based on the size of the network First number in dotted-decimal format determines class is Class A is Class C First number also determines subnet mask Class Address Range Subnet Mask Class A Class B Class C

53 Classes of IP Addresses Some addresses are reserved (the loopback address) is reserved for testing Three ranges are reserved for private networks thru thru thru One range is reserved for Automatic Private IP Addressing thru

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, 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 IP address Subnet Mask 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 LANs) 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) CPU1 Subnet 1 Network ID Subnet 2 Network ID CPU2 ` ` ` ` Router ` Default gateway Default gateway `

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 Broadcast NetBIOS cache View with NBTSTAT C

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 Automatically address

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/Vista/7 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 thru with a subnet mask of No routing capabilities DHCP can t be reached APIPA address assigned DHCP ` CPU1 ` Router ` ` `

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 \\SERVER1\FREDC Computer name Share name Can enter directly from Run line to access UNC path

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 Essentials CompTIA A+ Essentials Getting the Right Sound Card Installing and Configuring a Wireless Network

74 Introduction Wireless networks are still 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 standard Based on Bluetooth technology

75 Wireless Networking Components Many capabilities built-in today Infrared ports standard in laptops, PDAs, and highend 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 1. 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 2. 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 i ) Full upgrade to WEP Significant improvements Current wireless security standard

85 Wireless Networking Security Radius

86 Speed and Range Issues Wireless speeds range from 2 Mbps to 600 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

87 Wireless Networking Standards based wireless networking Four primary standards All can work in ad-hoc or infrastructure modes a b g Max 54 Mbps 11 Mbps 54 Mbps throughput 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,WPA2 Compatibility a b b, g

88 Wireless Networking Standards based wireless networking Three primary standards All can work in ad-hoc or infrastructure modes Max throughput Max range Frequency Security n 600 Mbps 300+ feet 2.4, 5 GHz SSID, MAC, WEP, WPA,WPA2 Compatibility a b,802.11g

89 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 Max throughput Max range Security Compatibility Communication mode Infrared (IrDA) Up to 4 Mbps 1 meter (39 inches) None IrDA Point-to-point ad-hoc

90 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

91 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

92 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

93 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

94 Configuring Wireless Networks NETGEAR wireless configuration utility

95 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 ) 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

96 Configuring Wireless Networks Sample home page

97 Configuring Wireless Networks Configuring MAC address filtering

98 Configuring Wireless Networks Configuring encryption

99 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

100 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

101 Troubleshooting Networks

102 Troubleshooting Networks Networked and non-networked situations differ drastically Networked situations add complexity If a user can t print from CPU1, it could be due to many possible problems on the network. Print server ` CPU1 ` ` Router or switch ` Networked printer

103 Troubleshooting Networks 1. Verify the symptom Talk with the user to try to get a precise description of the symptoms 2. When did it happen? Does it happen during boot, when the OS loads, or after the system has been running for a while? 3. What has changed? Try to find out if anything has changed Even recent changes before the problem began occurring

104 Troubleshooting Networks 4. Check the environment Heat, humidity, dirt What OS? What applications? Do others use the computer? 5. Reproduce the problem If a problem happens only once, it s not a problem Otherwise, try to make the problem happen again 6. Isolate the symptom Hardware remove suspect parts Software remove background programs or boot into Safe Mode

105 Troubleshooting Networks 7. 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 8. Research Use search engines on the Internet 9. 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

106 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 Transport TCP/UDP operate here the Layer 5: Sausage Session Manages connections Layer 6: Pizza Presentation Describes how to present data Layer 7: Away Application Interacts with user

107 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

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