Transcript aa7c78b8-a869-4f32-9a50

Case Study:
Pat Lee’s Home PC
Network
Chapter 1a
Updated January 2007
Panko’s
Business Data Networks and Telecommunications, 6th edition
Copyright 2007 Prentice-Hall
May only be used by adopters of the book
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-2
Figure 1a-2: Coaxial Cable
Common
Axis
Inner
Outer
Conductor
Conductor
(wire)
Insulation (cylinder)
Insulation
Two conductors
are required
for
Two conductors
are required
for transmission
1a-3
Figure 1a-1: Pat Lee’s Home Network
1.
Coaxial Cable
to ISP
2.
Cable
Modem
3. UTP Cord
4.
Access
Router
1a-4
Figure 1a-1: Pat Lee’s Home Network, Continued
6.
A1-BD-33-6E-C7-BB
PC in Emily’s Room
4.
Access
Router
5. UTP
Cord
5. UTP
Cord
6.
B2-CD-13-5B-E4-65
PC in Study
1a-5
Figure 1a-5: Unshielded Twisted Pair (UTP) Cord
With RJ-45 Connector
4-Pair Unshielded Twisted Pair (UTP)
Industry Standard Pen
8-Pin RJ-45 Connector
UTP Cord
1a-6
Figure 1a-1: Pat Lee’s Home Network, Continued
6.
A1-BD-33-6E-C7-BB
PC in Emily’s Room
7. File
Sharing
6.
B2-CD-13-5B-E4-65
PC in Study
1a-7
Figure 1a-1: Pat Lee’s Home Network, Continued
6.
A1-BD-33-6E-C7-BB
PC in Emily’s Room
8. Printer
Sharing
6.
B2-CD-13-5B-E4-65
PC in Study
1a-8
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-9
Figure 1a-4: Device Drivers
Operating System
NIC
Device
Driver
NIC
Hard Drive
Device
Driver
Hard Drive
Printer
Device
Driver
Printer
1a-10
Figure 1a-7: Home Network Access Router
About 4 inches (10 cm) Wide
Power
Jack for
External
Power
Switch Ports
UTP Cords
Run to Stations
WAN Port
UTP Cord
Runs to
Cable Modem
1a-11
Figure 1a-9: Ethernet Switch Operation
Switching Table
Port Host
10
A1-44-D5-1F-AA-4C
13
B2-CD-13-5B-E4-65
15
C3-2D-55-3B-A9-4F
16
D4-47-55-C4-B6-9F
Ethernet Switch
UTP
UTP
Frame To C3…
A1-44-D5-1F-AA-4C
UTP
UTP
D4-47-55-C4-B6-9F
Frame To C3…
C3-2D-55-3B-A9-4F
B2-CD-13-5B-E4-65
1a-12
Figure 1a-8: Logical Functions of the Access
Router
Cable
Modem
Access Router
Router Function
DHCP
Server
Function
NAT
Function
Switch Function
1a-13
Figure 1a-10: Dynamic Host Configuration
Protocol (DHCP)
ISP
DHCP Server
Cable
Modem
1.
IP Address =
60.47.112.6
Access Router
A1-BD-33-6E-C7-BB
PC in Emily’s Room
The ISP only
Gives each home a
Single IP addressB2-CD-13-5B-E4-65
PC in Study
A DHCP Server
provides User PCs with
a temporary IP Address
each time the user
connects to the Internet
1a-14
Figure 1a-10: Dynamic Host Configuration
Protocol (DHCP)
ISP
DHCP Server
A1-BD-33-6E-C7-BB
IP Address = 192.168.0.3
PC in Emily’s Room
1.
IP Address =
60.47.112.6
Internal
DHCP
Server
Access Router
2. IP Address =
192.168.0.3
2. IP Address =
192.168.0.2
The access router’s
internal DHCP server
gives private IP
Addresses to each PC
B2-CD-13-5B-E4-65
IP Address = 192.168.0.2
PC in Study
1a-15
Figure 1a-11: Network Address Translation (NAT)
2. Packet from
60.47.112.6
Webserver
IP Address=
123.7.86.285
Cable
Modem
Internal
NAT
Module
Access Router
The access router’s NAT
module translates between the
private IP Addresses and
the single ISP-given IP Address
1. Packet from
192.168.0.2
PC in Study
192.168.0.2
1a-16
Figure 1a-11: Network Address Translation (NAT),
Continued
3.
Packet
to
60.47.112.6
Webserver
IP Address=
123.7.86.285
Cable
Modem
Internal
NAT
Module
Access
Router
4. Packet to
192.168.0.2
PC in Study
192.168.0.2
1a-17
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-18
Figure 1a-12: Pat Lee’s Wireless LAN
Option with Separate Wireless Access Point
Wireless
Access Point
Access
Router
UTP Cord
A1-BD-33-6E-C7-BB
PC in Emily's Room
with Wireless NIC
Wireless
Communication
UTP Cord
B2-CD-13-5B-E4-65
PC in Study
Note: This option is rarely economical today
1a-19
Figure 1a-12: Pat Lee’s Wireless LAN
Option with Access Router with Integrated Wireless Access Point Functionality
A1-BD-33-6E-C7-BB
PC in Emily's Room
with Wireless NIC
Wireless
Communication
Access Router
with Built-in
Wireless Access Point
Functionality
1a-20
Figure 1a-13: Access Router with Wireless Access
Point and Wireless NICs
Access Router with
Wireless
Access Point
Internal
Wireless
NIC
Antenna
PC Card or
ExpressCard
Wireless NIC
Antenna
External Wireless
NIC with
USB Connector
1a-21
Configuration
Not in the
Book
• 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.
1a-22
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-23
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-24
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-25
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
1a-26