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Case Study:Pat Lee’s Home PC Network
Chapter 1a
Panko’s Business Data Networks and Telecommunications, 6th edition
Copyright 2007 Prentice-Hall May only be used by adopters of the book
1a-2
Pat Lee’s Home Network
• Pat Lee is a vice president at FBP
• Wants a network in her home
– Family’s main computer is the downstairs PC
– Daughter Emily has a PC in her room
– Wants to connect both to the Internet through a broadband (high-speed) cable modem service
• Perspective
– A small LAN but has all the key network elements
1a-3
Figure 1a-1: Pat Lee’s Home Network
1.Coaxial Cable
to ISP
2.Cable
Modem
3. UTP Cord
4.AccessRouter
1a-4
Figure 1a-2: Coaxial Cable
InnerConductor
(wire) Insulation Insulation
OuterConductor(cylinder)
CommonAxis
Two conductors are required forTwo conductors are required for transmission
1a-5
Figure 1a-1: Pat Lee’s Home Network, Continued
5. UTPCord
5. UTPCord
6.B2-CD-13-5B-E4-65
PC in Study
6.A1-BD-33-6E-C7-BBPC in Emily’s Room
4.AccessRouter
1a-6
Figure 1a-5: Unshielded Twisted Pair (UTP) Cord With RJ-45 Connector
8-Pin RJ-45 Connector
4-Pair Unshielded Twisted Pair (UTP)
Industry Standard Pen
UTP Cord
1a-7
Figure 1a-1: Pat Lee’s Home Network, Continued
6.B2-CD-13-5B-E4-65
PC in Study
6.A1-BD-33-6E-C7-BBPC in Emily’s Room
7. FileSharing
1a-8
Figure 1a-1: Pat Lee’s Home Network, Continued
6.B2-CD-13-5B-E4-65
PC in Study
6.A1-BD-33-6E-C7-BBPC in Emily’s Room
8. PrinterSharing
1a-9
Figure 1a-3: Network Interface Cards (NICs)
Internal NIC. Installed inside systems unit. Plugged into expansion slot on the mother board.
PC Card NIC. Installed in PC Card slot in notebook and some PDAs.
1a-10
Internal NIC
RJ-45Jack
PCI Connector Pins
1a-11
Figure 1a-6: UTP Cord RJ-45 Connector and Jack
RJ-45 JackOn a Wall
On a Switchor
on a NIC
RJ-45Connector
UTP Cord---
About as thickas a pencil
---Rugged and
Flexible
1a-12
Computer Mother Board
• Mother BoardPCI Slots
for Expansion Boards(NICs, etc.)
Slots for RAM
Slot forMicroprocessor
(Pentium 4)
1a-13
Mother Board and Expansion Boards
ConnectorExpansion Board
(NIC)Expansion
Slots
Mother Board
1a-14
Figure 1a-4: Device Drivers
Operating System
NICDeviceDriver
Hard DriveDeviceDriver
PrinterDeviceDriver
NIC PrinterHard Drive
1a-15
Figure 1a-7: Home Network Access Router
Switch PortsUTP Cords
Run to Stations
WAN PortUTP CordRuns to
Cable Modem
About 4 inches (10 cm) Wide
PowerJack forExternalPower
1a-16
Figure 1a-9: Ethernet Switch Operation
Switching TablePort Host 10 A1-44-D5-1F-AA-4C13 B2-CD-13-5B-E4-6515 C3-2D-55-3B-A9-4F16 D4-47-55-C4-B6-9F
UTP
UTPUTPUTP
Ethernet Switch
A1-44-D5-1F-AA-4C B2-CD-13-5B-E4-65
D4-47-55-C4-B6-9F
C3-2D-55-3B-A9-4F
Frame To C3…Frame To C3…
1a-17
Figure 1a-8: Logical Functions of the Access Router
DHCPServer
Function
Router Function
NATFunction
Switch Function
Access Router
CableModem
1a-18
Figure 1a-10: Dynamic Host Configuration Protocol (DHCP)
Access Router
CableModem
A1-BD-33-6E-C7-BBPC in Emily’s Room
B2-CD-13-5B-E4-65PC in Study
ISPDHCP Server
1.IP Address =60.47.112.6
A DHCP Serverprovides User PCs witha temporary IP Address
each time the userconnects to the Internet
The ISP onlyGives each home aSingle IP address
1a-19
Figure 1a-10: Dynamic Host Configuration Protocol (DHCP)
InternalDHCPServer
Access Router
A1-BD-33-6E-C7-BBIP Address = 192.168.0.3
PC in Emily’s Room
B2-CD-13-5B-E4-65IP Address = 192.168.0.2
PC in Study
ISPDHCP Server
1.IP Address =60.47.112.6
2. IP Address =192.168.0.2
2. IP Address =192.168.0.3
The access router’sinternal DHCP server
gives private IPAddresses to each PC
1a-20
Figure 1a-11: Network Address Translation (NAT)
Access Router
CableModem
WebserverIP Address=123.7.86.285
1. Packet from192.168.0.2
InternalNAT
Module
PC in Study192.168.0.2
2. Packet from60.47.112.6
The access router’s NATmodule translates between the
private IP Addresses andthe single ISP-given IP Address
1a-21
Figure 1a-11: Network Address Translation (NAT), Continued
AccessRouter
CableModem
WebserverIP Address=123.7.86.285
4. Packet to192.168.0.2
InternalNAT
Module
PC in Study192.168.0.2
3.Packet
to60.47.112.6
1a-22
Perspective
• Pat Lee would like to serve the upstairs computer wirelessly
• This requires a wireless access point connected to the router or built into the router
• The upstairs computer must have a wireless NIC
• The downstairs computer, which is next to the access router, will still be connected via UTP
• If a separate wireless access point is used, it must be connected to the access router via UTP
1a-23
Figure 1a-12: Pat Lee’s Wireless LAN
AccessRouter
A1-BD-33-6E-C7-BBPC in Emily's Roomwith Wireless NIC
B2-CD-13-5B-E4-65PC in Study
UTP Cord
Option with Separate Wireless Access Point
UTP Cord
WirelessAccess Point
WirelessCommunication
1a-24
Figure 1a-12: Pat Lee’s Wireless LAN
Access Routerwith Built-in
Wireless Access PointFunctionality
A1-BD-33-6E-C7-BBPC in Emily's Roomwith Wireless NIC
Option with Access Router with Integrated Wireless Access Point Functionality
WirelessCommunication
1a-25
Figure 1a-13: Access Router with Wireless Access Point and Wireless NICs
Access Router withWireless
Access Point
InternalWireless
NIC
External WirelessNIC with
USB Connector
PC Card orExpressCardWireless NIC
Antenna
Antenna
1a-26
Configuration
• Each computer must be configured for communication with the outside world. See Chapter 1b for details.
• Each computer must be configured for file and print sharing. See Chapter 1b for details.
• The access router has a built-in webserver, allowing either of the two PCs to configure it using a browser.
Not in theBook
1a-27
Figure 1a-14: Peer-to-Peer Service Versus Dedicated Servers
• Peer-to-Peer Networks
– Clients serving other clients
– Inexpensive—no need to purchase a dedicated server
– Operational problems for other users if a user PC is turned off or crashes
– Poor security: No password or shared password for shared directories
1a-28
Figure 1a-14: Peer-to-Peer Service Versus Dedicated Servers
• Dedicated Servers
– Servers that are not also used simultaneously as user PCs
– Do not use standard client versions of Microsoft Windows (XP, and so forth)
– They use special server operating systems
• Known for historical reasons as network operating systems (NOSs)
• One popular NOS is Microsoft Windows (latest version is Windows Server 2003)
• Another is Unix, which has versions for PCs (Linux, BSD, etc.)
1a-29
Figure 1a-14: Peer-to-Peer Service Versus Dedicated Servers
• Dedicated Servers
– NOSs for dedicated servers are rich in functionality
• They are designed to serve many users with many services
• Have strong security
– Unfortunately, dedicated servers are very expensive
– Installation requires specialized training
– Make no sense for home use
1a-30
Figure 1a-14: Peer-to-Peer Service Versus Dedicated Servers
• Network Attached Storage (NAS) Units
– Boxes that cost $200 to $500
– Contain a large shared hard drive
– RJ-45 plugs allow the NAS to be connected to the switch in the access router via UTP
– No mouse or keyboard; has a built-in webserver that can be managed remotely by a client PC
– Do not lose availability when a user PC is turned off or crashes
– Better security than PC file service
– Backup is crucial