Transcript A+ Guide to Managing and Maintaining your PC, 6e

A+ Guide to Managing and
Maintaining your PC, 6e
Chapter 17
PCs on a Network
Objectives
• Learn about different types of physical network
architectures
• Learn how networking works with Windows
• Learn how to install a network card and connect to a
network
• Learn about sharing resources on a network
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Objectives (continued)
• Learn how to set up and secure a wireless network
• Learn about troubleshooting tools and tips for
network connections
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Introduction
• Topics covered in this chapter:
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Technologies used to build networks
How Windows supports a network connection
How to connect a computer to a network
How network share resources are shared
How switches and routers interface networks
How to setup and secure a wireless network
How to troubleshoot a network connection
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Physical Network Architectures
• Elements providing an overview of networks
– The different sizes of networks
– The different technologies used by networks
– Some networking terms
• Network types commonly encountered
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Ethernet
Wireless networks
Telephone networks
Mostly outdated token ring and FDDI networks
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Sizes of Networks
• A network links two or more computers
• PAN (personal area network)
– Consists of personal devices at close range
• LAN (local area network)
– Covers a small local area such as a home, or office
• MAN (metropolitan area network)
– Covers a large campus or city
• WAN (wide area network)
– Covers a large geographical area; e.g., the Internet
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Networking Technologies
• Factors driving network evolution:
– The type of data the network is intended to support
– The data capacity on the network
– How a network is to fit among other networks
• Bandwidth (data throughput or line speed):
– Analog systems: measured in cycles/sec (hertz or Hz)
– Digital systems: measured in bps, Kbps, or Mbps
• As networks grow, the need for bandwidth grows
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Additional Terms Used in Networking
• Node (host): one device on a network; e.g., server
• Network adapter: interfaces a PC with a network
– Network interface card (NIC): fits in a PCI slot
• Adapter (MAC, physical, or hardware) address:
– 48-bit (6-byte) id number hard-coded on card
– Example: 00-0C-6E-4E-AB-A5
• Network protocols: rules of communication
• Packets (datagrams or frames)
– Basic unit of data transmitted on a network
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Figure 17-1 Ethernet network card showing its MAC address
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Introducing Ethernet
• Ethernet types (categorized by speed):
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10-Mbps Ethernet
100-Mbps or Fast Ethernet
1000-Mbps or Gigabit Ethernet
10-Gigabit Ethernet
• Types of cabling used:
– Two kinds of twisted-pair
• Unshielded twisted pair (UTP): four pairs of twisted wire
• Shielded twisted pair (STP): protected from EMI
– Coaxial cable: single copper wire with braided shield
– Fiber-optic: glass strands inside protective tubing
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Table 17-2 Variations of Ethernet and Ethernet cabling
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Figure 17-4 Fiber-optic cables contain a glass core for
transmitting light
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Introducing Ethernet (continued)
• Topology: arrangement of nodes in a network
• Bus topology: connects all nodes with a line (no hub)
• Star topology
– Connects nodes to central hub (or switch)
– The hub broadcasts a data packet to every device
– Switch uses a table to route packet to receiving device
• Scale networks by adding switches
• Star bus topology:
– Multiple switches form a bus network
– Nodes connected to each switch form a star
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Figure 17-6 Nodes on an Ethernet network can be connected to one
another in a star or bus formation
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Figure 17-10 A star bus network uses more than one switch
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Introducing Ethernet (continued)
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Attenuation: the weakening of a transmitted signal
Repeater: device used to amplify a signal in a LAN
Amplifier repeater: simply amplifies incoming signal
Signal-regenerating repeater
– Reads and copies the signal (without noise)
– Transmits an exact duplicate of the original
• Ethernet uses a signal-regenerating repeater
– A switch or hub can act as the repeater
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Figure 17-14 A repeater on a network restores the clarity of the signal,
which degrades over a distance because of attenuation
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Wireless Networks
• Use radio waves or infrared light to connect PCs
• Popular in places where cables are difficult to install
• 802.11wireless (Wi-Fi or Wireless Fidelity)
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Types: 802.11g (most popular), 802.11b, 802.11a
Two new standards: 802.11k and 802.11r
Ad hoc mode: directly links two wireless devices
Access point (AP): connects wireless device to LAN
• WiMAX (802.16 Wireless/802.16d and 802.16e)
– Used in public hot spots and as a last mile solution
• Bluetooth: short range standard; e.g., optical mouse
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Figure 17-16 Nodes on a wireless LAN connect to a cabled network by
way of an access point
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Telephone Networks
• Plain old telephone service (POTS)
– Switching creates closed circuits between phones
• VoIP (Voice over Internet Protocol)
– Uses packets of data to communicate
• Cellular WAN
– Made up cells created by base stations
• Cellular WAN standards
– GSM (Global System for Mobile Communications)
– CDMA (Code Division Multiple Access)
– TDMA (Time Division Multiple Access)
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Figure 17-20 A cellular WAN is made up of many cells
that provide coverage over a wide area
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Telephone Networks (continued)
• General Packet Radio Service (GPRS)
– New communication protocol using data packets
• Two types of transmission:
– Full-duplex: allows both users to talk and transmit
– Half-duplex: allows only one user on a channel
• Satellite phone: communicates with satellites
• Cordless phone: communicates with phone base
• Radio phone: uses VHF radio waves
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Token Ring and FDDI
• Token Ring is physically a star, logically a ring
• Components of a token ring:
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Controlled Access Unit (CAU)
Multistation Access Unit (MSAU or MAU)
Token Ring LAN card connecting node to MSAU
UTP or STP cables with two twisted pairs
RJ-45 or Universal Data Connector (UDC)
• Fiber Distributed Data Interface (FDDI)
– Uses a token that travels in a ring like a Token Ring
– Data frames travel on the ring without the token
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Figure 17-21 Full-duplex and half-duplex transmissions
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Windows on a Network
• Major software components on a network
• An operating system installed on each PC
– Network operating system (NOS) for larger networks
• Peer-to-peer network (workgroup)
– Each PC has the same authority on the network
• Client/server model (domain)
– Access to network resources controlled by an NOS
– Server is called a domain controller
• A few network operating systems
– Windows 2003 Server, Novell NetWare, Linux
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Four Suites of Protocols
• TCP/IP (Transmission Control Protocol/Internet
Protocol)
– Primary protocol used on the Internet
• IPX/SPX (Internetwork Packet Exchange/Sequenced
Packet Exchange)
– Designed for use with Novell NetWare
• NetBEUI (NetBIOS Extended User Interface)
– Supports NetBIOS (Network Basic Input/Output System)
• AppleTalk
– Proprietary networking protocol suite for Macs
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Figure 17-25 An operating system can use more than one method to
address a computer on the network, but at the network level, a MAC
address is always used to address a device on the network
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Four Suites of Protocols (continued)
• Using a protocol on the network
– Install a NIC card in the computer
– Connect network cable to network device; e.g., a switch
– NIC card binds to higher level protocol; e.g., TCP/IP
• How to identify which protocols are used in Windows
– Look at the properties of a network connection
• More than one OS protocol can be used on a network
• New protocols may be installed
• Network printers can be accessed in various ways
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Figure 17-26 Three Windows XP network protocols are installed and two
protocols are bound to this network card
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Addressing on a Network
• Four methods used to identify devices and programs
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Using a MAC address
Using an IP address
Using character-based names (host, domain, NetBIOS)
Using a Port address
• IP addresses
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Used in TCP/IP to identify any device on the network
4 bytes (octets) separated by dots; e.g., 190.180.40.120
System allows for up to 4.3 billion IP addresses
First part identifies network, last part identifies host
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Figure 17-27 Computers on the same LAN use MAC addresses to
communicate, but computers on different LANs use IP addresses to
communicate over the Internet
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Addressing on a Network (continued)
• Classes of IP addresses
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Class A: first octet for network, remainder for host
Class B: two octets for network, remainder for host
Class C: three octets for network, remainder for host
Class D: reserved for multicasting
Class E: reserved for research
• Subnet mask
– Octets used to identify if PCs are in same network
– Ex: if subnet is 255.0.0.0, the first octets must match
– Two types: classful and classless (CIDR)
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Table 17-3 Classes of IP addresses
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Figure 17-31 The network portion and host portion for each class of IP addresses
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Addressing on a Network (continued)
• IP address categories
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Public IP address: available for use on the Internet
Private IP address: only used on a private intranet
Static IP address: permanently assigned to a node
Dynamic IP address: assigned for current session
• Solutions for IP address shortages
– 1. Private IP addresses
– 2. Dynamic IP addressing (may be combined with 1)
• DHCP (Dynamic Host Configuration Protocol) server
– Manages dynamically assigned IP addresses
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Figure 17-33 A DHCP server has a range of IP addresses it can assign
to clients on the network
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Addressing on a Network (continued)
• Network address translation (NAT)
– Presents public IP address for PC with private address
– A proxy server makes the IP address substitutions
• Proxy server: node between the network and the Internet
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Router can act as proxy server, DHCP server, firewall
Name resolution: links a name to an IP address
DNS (Domain Name System): tracks host names
WINS (Windows Internet Naming Service)
– Tracks NetBIOS names; e.g., joesmith, Workstation12
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How Computers Find Each Other on a
LAN
• PC must acquire IP address of another PC for a link
• Methods for discovering IP address of another PC
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The computer checks the NetBIOS name cache
If WINS server address is known, PC queries server
Computer uses broadcast to query nodes on LAN
The computer checks a file named LMHosts
The computer checks the file named Hosts
If DNS server address is known, PC queries server
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Figure 17-35 An entry in your client Hosts file will tell the client the IP address
of an intranet Web site when no DNS service is running on the network
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Installing a NIC and Connecting to a
Network
• Components needed to connect a PC to a network
– NIC and network port or wireless NIC card in the PC
– Patch cable
– Device for the PC to connect to, such as a router
• NIC card selection criteria
– NIC should match type of bus on motherboard
– NIC should match speed and type of network
– Wireless NIC should match network technology
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Installing a NIC Using Windows
2000/XP
• Overview of installation steps
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Determine whether driver or NIC is installed first
If NIC precedes driver, install NIC and turn on PC
Follow instructions in Found New Hardware Wizard
Verify driver installation using the Device Manager
Update the driver if necessary
Connect patch cable to NIC port and network switch
• Configuring Windows 2000/XP to use a network
– Name computer in System Properties dialog box
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Figure 17-37 Windows XP uses the Computer Name Changes dialog box to
assign a host name to a computer on a network
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Installing a NIC Using Windows
2000/XP (continued)
• Questions to ask before configuring TCP/IP
– Will the PC use dynamic or static IP addressing?
– What are the IP address, subnet mask, default gateway?
• A question to ask if static IP addressing is used
– Do you use DNS?
• If so, what are the IP addresses of your DNS servers?
– Is a proxy server used to connect to other networks?
• If so, what is the IP address of the proxy server?
• Gateway: device that connects two networks
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Installing a NIC Using Windows
2000/XP (continued)
• Internet Protocol (TCP/IP) Properties dialog box
– Used to configure TCP/IP under Windows XP
– Dialog opened from Properties of Local Area Connection
• NWLink or NetBEUI protocol
– Used for network communication (excluding the Internet)
– Can be used in combination with TCP/IP
– Installed from Properties of Local Area Connection
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Figure 17-39 To configure TCP/IP under Windows XP, use the
Internet Protocol (TCP/IP) Properties dialog box
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Installing a NIC Using Windows 9x/Me
• Overview of installation steps:
– Physically install the NIC and turn on the PC
– Follow instructions of the Wizard
– Verify the installation using Device Manager
• Assigning a computer name
– Access Identification tab in Network dialog box
– Enter names of computer and workgroup
– Verify assignment in Network Neighborhood window
• Installing and configuring TCP/IP using Windows 98
– Use functions in the Network window
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Figure 17-45 To configure TCP/IP in Windows 98, select the binding and click
Properties to view the TCP/IP Properties dialog box
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Installing a Wireless Adapter in a
Notebook
• Wireless adapter uses a USB port or PC Card slot
• Installation package includes a CD and accessories
• Overview of steps for installing a Linksys adapter
– Install the software from the setup CD
– Plug the wireless adapter into a USB port
– Launch Found New Hardware and follow instructions
• Managing the issue of an unsigned driver
– Find approved driver or continue installation
• Deciding which installation utility to use
– Choose manufacturer’s utility over Windows XP’s
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Figure 17-50 Plug the wireless USB adapter into the USB port
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Installing a Wireless Adapter in a
Notebook (continued)
• Information displayed about a current connection:
– MAC address of access point device used by adapter
– The current channel the connection is using
– Transfer rate, throughput, link quality, signal strength
• Configuration changes you can make:
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Mode or network type
The SSID (service set identifier)
Encryption settings
Tx rate
TCP/IP configuration
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Figure 17-54 Opening screen to configure a Linksys wireless adapter
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Installing a Wireless Adapter in a
Notebook (continued)
• Connecting to a public hot spot using Windows XP
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Open Wireless Network Connection dialog box
Select unsecured network from list and click Connect
Open a browser to test the connection
View link in Wireless Network Connection Status box
• Two ways to troubleshoot a connection
– Add network SSID in Wireless network properties
– Provide MAC address to network administrator
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Figure 17-62 Enter the SSID of a hot spot to which you want to connect
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Using Resources on the Network
• Topics to cover:
– How to share folders and files
– How to share applications
– How to share entire hard drives
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Sharing Files, Folders, and
Applications
• PCs in same workgroup or domain share resources
• How to makes network shares available
– Use My Network Places in Windows 2000/XP
– Use Network Neighborhood in Windows 9x/Me
• Windows components required for sharing resources
– Client for Microsoft Networks
– Printer Sharing for Microsoft Networks
• Creating a network share in Windows
– Use Sharing tab in Properties dialog box of target
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Figure 17-65 View and access shared resources on the network using My
Network Places in Windows XP
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Network Drive Maps
• Make the client PC appear to have a new hard drive
– Physical hard drive space is on the host (the server)
• Network File System (NFS)
– Manages network drive maps between client and server
– Is a type of distributed file system (DFS)
– Provides more for highly reliable file sharing
• Overview of steps to create a network drive map:
– Create a network share on the host
– Access network using remote computer (client)
– Use Map Network Drive to map host drive to client
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Figure 17-71 Mapping a network drive to a host computer
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What If You Don't Want To Share?
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Disable File and Printer Sharing
Hide PC from others looking at My Network Places
Hide a shared folder
Make your personal folders private
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How to Set Up Your Own Wireless
Network
• Two principal steps:
– Buy a wireless access point
– Configure AP and wireless PC for communication
• Providing security is critical for a successful network
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Security on a Wireless LAN
• Methods for securing a wireless connection:
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Disable SSID broadcasting
Filter MAC addresses
Data encryption; e.g., WPA (WiFi Protected Access)
Change firmware default settings
Update firmware
Use a firewall
Virtual private network (VPN)
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Figure 17-74 With tunneling, packets can travel over a wireless LAN and
the Internet in a virtual private network (VPN), but WEP or WPA applies
only to the wireless connection
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Choosing a Wireless Access Point
• Selection criteria
– The ability to use multiple security measures
– Supports for the 802.11 b/g wireless standards
– Good hardware reviews from other users
• An access point can be a standalone device
• An access point can also serve multiple purposes
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Configure and Test Your Wireless
Network
• Installing the hardware
– Position device and plug it in
– Connect the device using a network or USB cable
• Access point configuration is saved on firmware
• Configuring the access point
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Change default password to the administrative utility
Select basic wireless settings, such as the channel
Set up data encryption
Choose whether to filter MAC addresses
Save the settings and test the connection
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Figure 17-79 This wireless access point supports several encryption methods
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Troubleshooting a Network Connection
• Some symptoms indicating a faulty NIC:
– You cannot make a connection to the network.
– My Network Places does not show any other PCs
– An error message displays during driver installation
• Displaying TCP/IP connection information
– Use Ipconfig under Windows 2000/XP
– Use Winipcfg under Windows 9x/Me
• Ping (Packet Internet Groper) diagnostic tool
– Sends a signal to a remote computer
– If remote PC is online and senses signal, it responds
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Summary
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Network: system interconnecting two or more PCs
Basic network types: PANs, LANs, MANs, and WANs
Bandwidth: amount of data transmitted per unit time
Ethernet topologies: bus, star, star bus
Wireless standards: 802.11g/b/a/k/r, WiMAX,
Bluetooth
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Summary (continued)
• Telephone technologies: POTS, VoIP, Cellular WAN,
satellite phone, cordless phone, and radio phone
• OS level protocols: TCP/IP, IPX/SPX, Net BEUI,
AppleTalk
• IP address: 32-bit address identifying network node
• Local Area Connection dialog box: used to install
and modify communication protocols
• Shared network resources: files, folders, and devices
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