Introduction

Transcription

Introduction

Not for distribution to students
Introduction
Chapter 1
Panko’s
Business Data Networks and Telecommunications, 5th edition
Copyright 2005 Prentice-Hall
The Chapter
z
This chapter is a survey of
the key concepts we will
see in this course
z
The rest of the book
essentially fleshes out the
concepts we will see in
this chapter
2
1
The Chapter
z
Networking is a Head
Game
z
There is a lot of
information to master
z
There are many TLAs
(three-letter
acronyms)
z
For design and
troubleshooting, you
must know everything
to do anything.
3
Learning Objectives
z
By the end of this chapter, you should be able
to
z
Discuss the First Bank of Paradise (FBP), our
running case study for this book.
z
Discuss the major types of networked applications.
z
List the eight elements of networks.
z
Explain the major types of networks in businesses:
LANs, WANs, internets, intranets, and extranets.
4
2
Learning Objectives
z
to
z
Discuss major concerns for network
managers: staffing, network architecture,
standards, security, wireless networking,
efficiency, and quality of service (QoS).
z
Explain the elements and operation of a
small home PC network using a LAN.
5
Learning Objectives
z
to
z
Use some key hands-on network
management tools, including bandwidth
measurement services, ping, ping 127.0.0.1,
tracert, ipconfig, winipconfig, nslookup, and
the use of Windows Calculator to compute
dotted decimal notation IP addresses.
6
3
First Bank of Paradise (FBP)
z
The book’s running case study
z
Composite mid-size bank in Hawaii
z
Banks are fairly “typical” firms, although they
have stronger need for security
z
Warren Chun is the chief information officer
(CIO)
z
Yvonne Champion is the network manager
7
First Bank of Paradise (FBP), Continued
z
Annual Revenues: $4 Billion
z
Operations
z
z
50 Branches
z
350 ATMs (Automated Teller Machines)
Network
z
500 Ethernet switches
z
400 Routers
8
4
First Bank of Paradise (FBP), Continued
z
z
Computers
z
2,000 desktop and notebook user PCs
z
200 Windows servers
z
30 Unix servers
z
10 Novell NetWare file servers
Information Systems Staff
z
150 people
9
Figure 1-1: Networked Applications at the First
Bank of Paradise
z
Networked Applications are
Applications Made Possible by
Networking
z
z
E-mail, etc.
Users Only Care About
Applications
z
The rest is just details to them
10
5
Figure 1-1: Networked Applications at the
First Bank of Paradise, Continued
z
E-Commerce
z
Buying and selling on the
Internet
z
Users typically interact with
databases
z
Customers will soon be
able to talk to customer
representatives while online
11
z
Transaction
Processing
z
Simple, highlystructured, and highvolume interactions,
such as check
processing
z
Built around
databases
z
External settlement
networks
12
6
z
Transaction Processing
z
Back-office transaction
processing applications
z Accounting, payroll,
purchasing, human
resources, etc.
z Functional databases in
individual departments
13
z
Office Applications
z
Word processing,
spreadsheeting, etc.
z
E-mail, instant messaging
(IM), and Web access
14
7
Figure 1-2: Elements of a Network
Message (Frame)
Application
Application
Client
Station
Switch
Server
Station
Networks connect
Switch
applications Trunk
on different stations.
AccessApplications
Switch
are
all users care about
Line
Trunk
Line
Line
Mobile Client
Station
Switch
Outside
World
Router
Mobile Client
Station
15
Figure 1-2: Elements of a Network, Continued
Message (Frame)
Application
Application
Client
Station
Switch
Server
Station
Networks connect stations:
Switch
clients (fixed and
mobile) and servers
Trunk
Access Switch
Line
Trunk
Line
Line
Mobile Client
Station
Switch
Outside
World
Router
Mobile Client
Station
16
8
Message (Frame)
Application
Application
Client
Station
Switch
Stations (and routers)
usually communicate
Access Switch
by sendingLine
messages
called frames
Mobile Client
Station
Trunk
Line
Server
The path Station
a frame takes
Switch
is called its data link
Trunk
Line
Switch
Outside
World
Router
Mobile Client
Station
17
Network Medium
z
Unshielded Twisted Pair (UTP) Cable
RJ 45 connector
18
9
Network Medium
z
Shielded Twisted Pair (STP) Cable
19
Network Medium
z
Coaxial Cable
50 Ohms (75 Ohms for Cable TV) BNC connector
20
10
Network Medium
z
Optical Fiber
21
Message (Frame)
Application
Application
Client
Station
Switch
Switch
Trunk
Access Switch
Switches
Linemove frames
Trunk
Line
to or closer to the destinationLine
station
Mobile Client
Station
Server
Station
Outside
World
Switches handle a packet sequentially
Switch
Router
Mobile Client
Station
22
11
Figures 1-6 and 1-7: Workgroup and Core
Switches
19 inches (48 cm) wide
Small Switches
(Stacked):
Workgroup Switches
To Link Stations
To Network
Central Core Switch
23
Data Source: www.dlink.com.tw
24
12
25
26
13
27
Message (Frame)
Application
Application
Client
Station
Switch
Access
Line
Server
Station
Routers connect networks
Switch
to the outside world;
Trunk
Switch Treated just like stations
Line
Trunk
Line
Mobile Client
Station
Outside
World
Switch
Mobile Client
Station
Router
28
14
Client
Station
Switch
Server
Station
Switch
Access Switch
Line
Mobile Client
Station
Trunk
Line
Trunk
Line
Switch
Trunk
Line
Outside
World
Router
Mobile Client
Station
29
Figure 1-2: Elements of a Network (Recap)
z
Applications (the only element that users care about)
z
Stations
z
z
Clients
Servers
z
Switches
z
Routers
z
Transmission Lines
z
z
z
Trunk lines
Access Lines
Messages (Frames)
Never talk about an
Innovation “reducing cost,”
“increasing speed,” etc.
without specifying
which element is
cheaper or faster.
For example, multiplexing
only reduces the cost of
trunk lines; other
costs are not decreased
30
15
Figure 1-3: Multiplexing in a Packet-Switched
Network
Trunk line
multiplexes the
messages of
different
conversations
AC
Client
Station A
AC
AC BD
BD
Mobile Client
Station B
AC
AC
Trunk Line
Access
Line
AC
This reduces
trunk line
costs through
cost sharing
by users
Server
Station C
BD
BD
Router D
31
LANs and WANs
z
LANs transmit data
within corporate sites
z
WANs transmit data
between corporate sites
z
Each LAN or WAN is a
single network
WAN
32
16
Figure 1-4: The First Bank of Paradise’s
Wide Area Networks (WANs)
North Shore
Operations
OC3 Private Line
T3
T3
Bank has multiple
facilities connected
by multiple WANs
Headquarters
33
Frame-Relay
z
使用虛擬線路(Permanent Virtual Circuits;PVC)供企業
做網路傳輸之網路服務
z
價格較專線便宜
z
適合多點互連
z
使用第二層傳輸
34
17
Private Line - Hinet
Data Source: www.hinet.net
35
Private Line - Sparq
Data Source: www.sparq.com.tw
36
18
Figure 1-5: Local Area Network (LAN) in a
Large Building
Multi-floor
Office Building
The bank has multiple
LANs—one at each site
37
Figure 1-5: Local Area Network (LAN) in a Large
Building, Continued
Wall Jack
Workgroup Switch
Workgroup Switch
To
WAN
Router
Core Switch
38
19
Internets
z
Most firms have multiple LANs and WANs.
z
They must create internets
z
An internet is a collection of networks connected by
routers so that any application on any host on any
single network can communicate with any
application on any other host on any other network
in the internet.
Application
Application
LAN
WAN
Router
LAN
Router
39
Figure 1-8: Internet with Three Networks
Host A
R1
Packet
Network X
Network Z
A packet goes all the
way across the internet;
It’s path is its route
Network Y
Route A-B
R2
Host B
40
20
Figure 1-8: Internet with Three Networks,
Continued
z
Messages in single networks (LANs or WANs) are
called frames
z
Message in internets are called packets
z
z
Travel from the source host to the destination host
across the entire internet
Within a single network, the packet is encapsulated in
(carried in) the network’s frame
Packet
Package
(Packet)
Truck
(frame)
Frame
41
Continued
Frame X
Details in
Network X
Packet
Data Link
A-R1
Switch
Host A
Switch
Server
Host
Switch
X1
Mobile Client
Host
Switch
X2
Route
A-B
Router R1
Network X
42
21
Continued
Details in
Network Y
To
Network X
Route
A-B
Router R1
Frame Y
Data Link
R1-R2
Packet
Router R2
To
Network Z
Network Y
43
Continued
Data Link
R2-B
Details in
Network Z
Packet
Frame Z
Switch
Z1
Host B
Switch
Router R2
Switch
Z2
Mobile Client
Hosts
Switch
Router
Network Z
44
22
Continued
z
In this internet with three networks, in a
transmission,
z
z
z
There is one packet
There are three frames (one in each network)
If a packet in an internet must pass through N
networks,
z
z
How many packets will be sent?
How many frames must carry the packet?
45
Continued
z
Lower-case internet is any internet
z
Upper-case Internet is the global Internet
46
23
Figure 1-11: The Internet
Webserver
User PC
Access
Line
The Internet Backbone
(Multiple Carriers)
Access
Line
Router
NAP
ISP 2 NAP
ISP 4
NAP
ISP 1
ISP 3
Internet
Service
Provider
For User PC
NAP = Network Access Point
Internet Service
Provider
For Webserver
47
Figures 1-9 and 1-10: Routers
Small Routers
Stacked
For Branch Offices
Large Routers
for Large Sites and ISPs
48
24
Router Products
49
Router Products
50
25
Figure 1-12: The Internet, internets,
Intranets, and Extranets
z
internets versus the Internet
z
Intranets
z
z
Internal internet for use within an organization
z
Based on the TCP/IP standards created for the
Internet
Extranets
z
Connect multiple firms
z Only some computers from each firm are on the
extranet
z
Use TCP/IP standards
51
Recap
z
z
Switches versus Routers
z
Switches move frames through single networks
(LANs or WANs)
z
Routers move packets through internets
Messages
z
Messages in single networks are called frames
z
Messages in internets are called packets
z
Packets are encapsulated within frames
52
26
Figure 1-13: Major Network Technical
Concerns
z
Network Architecture
z
A broad plan for how the firm will
connect all of its computers
within buildings (local area
networks), between sites (wide
area networks), and to the
Internet
z
New systems must fit the rules
of the architecture
z
Undisciplined growth in the past
z No overall plan
53
Concerns, Continued
z
z
Legacy networks
z
Use obsolete technologies that
do not fit the long-term
architecture
z
Many exist in the bank
z
Too expensive to replace
quickly; must live with many for
awhile
54
27
Concerns, Continued
z
z
Scalability
z The ability of selected technologies to be able to
handle growth efficiently
Poor
Scalability
Cost
Per
Bit
Good
Scalability
Demand
55
Concerns, Continued
z
Standards
z
Standards govern message interactions between
pairs of entities (Figure 1-14)
z
For example, HTTP request and response messages for
WWW access
Webserver
HTTP Request Message
Client PC
Browser
Client
Program
HTTP Response Message
Webserver
Application
Server
Program
56
28
Concerns, Continued
z
Standards
z
Standards create competition
z
This reduces costs
z
It also stimulates the development of new
features
z
Protects the business if the main vendors go
out of business
57
Concerns, Continued
z
Standards
z
Competing standards organizations create
incompatible standards
z
FBP will standardize to save money
z
LANs: FBP will standardize on Ethernet (some
legacy LAN technologies are still in use)
z
WAN standards: will have fewer but still two to four
z
Internetworking: will standardize on TCP/IP
58
29
Concerns, Continued
z
Security
z
A Major Problem
z
Many attacks
z
Growing trend toward
criminal attackers
59
Figure 1-15: Firewalls
Allowed Legitimate Border
Packet
Firewall
Attacker
Hardened
Server
Hardened
Client PC
Border firewall
should pass
legitimate packets
Log File
Legitimate
Packet
Legitimate
Host
Internal
Corporate
Network
60
30
Figure 1-15: Firewalls, Continued
Border firewall
should deny (drop)
Hardened and log
Server attack packets
Border
Firewall
Attack Packet
Denied
Attack
Packet
Hardened
Client PC
Log File
Network Management
Console
Attacker
Legitimate
Host
Internal
Corporate
Network
61
Concerns, Continued
z
Security
z
Virtual Private Networks (VPNs) (Figure 1-16)
z
Provide communication over the Internet with
added security
z
Cryptographic protection for confidentiality
(eavesdroppers cannot read)
z
Cryptographic authentication (confirms sender’s
identity)
62
31
Figure 1-16: Virtual Private Networks
(VPNs)
Site-to-Site VPN
Using Gateway
Client
VPN
Remote Access
Gateway PC 1
VPN Using
Corporate
Gateway
Site B
VPN
Gateway
Internal
Server
Corporate
Site A
Internet
Host-to-Host
VPN
Remote
Client PC 2
Remote Client PC 3
63
Figure 1-13: Major Network Management
Concerns, Continued
z
Wireless
Communication
z
To improve mobility
z
Drive-by hackers can
eavesdrop on internal
communication
z
Drive-by hackers can
break into the network
bypassing firewalls
Drive-By Hacker
64
32
Concerns, Continued
z
Need for Efficiency
z User demand is growing rapidly
z Budgets are growing slowly if at all
z For projects, need burning justification
z Still add new services by squeezing maximum
payback from each dollar
User Demand
Money/
Demand
Budget
Time
65
Concerns, Continued
z
Quality of Service (QoS)
QoS
z
Numerical objectives for performance
z
Transmission speed in bits per second (bps)
z
z
z
A bit is a single one or zero
NOT bytes per second
Increase by factors of 1000, not 1024
z kilobits per second (kbps)—lower-case k
z Megabits per second (Mbps)
z Gigabits per second (Gbps)
z Terabits per second (Tbps)
66
33
Concerns, Continued
z
Quality of Service
z
z
z
z
For Transmission Speed, have 1 to 3 places
BEFORE the decimal point.
Example
z .5 Mbps is wrong
New
z 500 kbps is correct
Not in the Book
Example
z 2,300 Mbps is wrong
z 2.3 Gbps is correct
Example
z 473.2 Mbps is correct
67
Concerns, Continued
z
Quality of Service
z
Typical transmission speeds in
most firms:
z
LANs: 100 Mbps to each
desktop
z
WANs: most site-to-site links
only are 56 kbps to a few
megabits per second because
long-distance transmission is
very expensive and so must
be used more sparingly
LANs:
100 Mbps
WANs:
56 kbps
to a few
Mbps
68
34
Concerns, Continued
z
Quality of Service
z
Congestion, Throughput, Latency, and
Response Time
z
Congestion: when there is too much traffic for
the network’s capacity
z
Throughput: The speed users actually see
(often much less than rated speed)
z
Individual throughput is less than total
throughput on shared-speed links
69
Concerns, Continued
z
Quality of Service
z
Congestion, Throughput,
Latency, and Response Time
z Latency: delay (usually
measured in milliseconds or
ms)
z
Within corporations, latency is
typically under 60 ms 90% of
the time
z
On the Internet, typically 30
ms to 150 ms
70
35
Concerns, Continued
z
Quality of Service
z
Congestion, Throughput, Latency, and Response
Time
z Response Time
z
The time to get a response after a user
issues a command
z
A quarter second
or less is good
71
Concerns, Continued
z
Availability
z
Availability is the percentage of
time a network can be used
z
Downtime: when the user cannot use the network
z
Want 24x7 availability
z
Telephone network gives 99.999% availability
z
Typical networks reach 98% today
72
36
Concerns, Continued
z
Error Rate
z
Measured as the percentage of messages
damaged or lost
z
Substantial error rates can disrupt applications
z
Substantial error rates generate more network
traffic because of retransmissions
73
Pat Lee’s Home Network
z
Pat Lee is a vice president at FBP
z
Wants a network in her home
z
z
Family’s main computer is the downstairs PC
z
Daughter Emily has a PC in her room
z
Wants to connect both to the Internet through a
broadband (high-speed) cable modem service
Perspective
z
A small LAN but has all the key network elements
74
37
Figure 1-18: Pat Lee’s Home Network
1.
Coaxial Cable
to ISP
2.
Cable
Modem
3. UTP Cord
4.
Access
Router
75
Figure 1-22: 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
76
38
Figure 1-18: Pat Lee’s Home Network, Continued
6.
A1-BD-33-6E-C7-BB
PC in Emily’s Room
5. UTP
Cord
5. UTP
Cord
6.
B2-CD-13-5B-E4-65
PC in Study
77
6.
A1-BD-33-6E-C7-BB
7. File
Sharing
6.
B2-CD-13-5B-E4-65
PC in Study
78
39
6.
A1-BD-33-6E-C7-BB
8. Printer
Sharing
6.
B2-CD-13-5B-E4-65
PC in Study
79
Figure 1-19: Network Interface Cards (NICs)
(Photo)
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.
80
40
Internal NIC
RJ-45
Jack
PCI Connector Pins
81
Computer Mother Board
z
Mother Board
PCI Slots
for Expansion Boards
(NICs, etc.)
Slots for RAM
Slot for
Microprocessor
(Pentium 4)
82
41
Mother Board and Expansion Boards
Expansion Board
(NIC)
Connector
Expansion
Slots
Mother Board
83
Figure 1-20: Unshielded Twisted Pair (UTP)
Cord With RJ-45 Connector (Photo)
4-Pair Unshielded Twisted Pair (UTP)
Industry Standard Pen
8-Pin RJ-45 Connector
UTP Cord
84
42
Figure 1-21: UTP Cord RJ-45 Connector and
Jack
UTP Cord
--About as thick
as a pencil
--Rugged and
Flexible
RJ-45 Jack
On a Wall
On a Switch
or
On a NIC
RJ-45
Connector
85
z
Unshielded Twisted Pair (UTP) Cable
Category 5E to 1G (Gigabit Ethernet)
Category 6, 7 in progress
RJ 45 connector
86
43
Figure 1-23: Logical Functions of the
Access Router
Cable
Modem
Access Router
Router Function
DHCP
Server
Function
NAT
Function
Switch Function
DHCP=Dynamic Host Configuration Protocol
NAT=Network Address Translation
87
Figure 1-24: 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
UTP
UTP
D4-47-55-C4-B6-9F
Frame To C3…
Frame To C3…
A1-44-D5-1F-AA-4C
C3-2D-55-3B-A9-4F
B2-CD-13-5B-E4-65
88
44
Figure 1-25: Frames and Packets
Cable
Modem
Packet in
DOCIS
Frame
Internal
Router
Access Router
Packet is always
carried (encapsulated)
in a frame
A1-BD-33-6E-C7-BB
IP address = 192.168.0.3
Packet in
Ethernet Frame
B2-CD-13-5B-E4-65
IP address = 192.168.0.2
PC in Study
89
Figure 1-26: Dynamic Host Configuration
Protocol (DHCP)
Cable
Modem
ISP
DHCP
Server
1.
IP Address =
60.47.112.6
Access Router
A1-BD-33-6E-C7-BB
The ISP only
Gives each home a
Single IP address B2-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
90
45
Figure 1-26: Dynamic Host Configuration
Protocol (DHCP), Continued
Cable
Modem
ISP
DHCP
Server
1.
IP Address =
60.47.112.6
A1-BD-33-6E-C7-BB
IP address = 192.168.0.3
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
91
Figure 1-27: 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
92
46
Figure 1-27: 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
93
Figure 1-28: The Domain Name System
(DNS), Continued
DNS Table
Originating
Host’s DNS
Resolver
Host Name
…
…
Voyager.cba.hawaii.edu
…
IP Address
…
…
128.171.17.13
…
DNS Request Message
“The host name is Voyager.cba.hawaii.edu”
DNS Response Message
“The IP address is 128.171.17.13”
DNS
Host
94
47
Figure 1-29: Converting Binary IP Addresses to
Dotted Decimal Notation
Binary
IP Address
8-Bit
Segments
Convert
Segments
to Decimal
Dotted
Decimal
Notation
01111111101010110001000100001101
01111111
10101011
00010001
00001101
127
171
17
13
127.171.17.13
95
IP Address
96
48
Figure 1-30: Windows Calculator
1. Open Calculator, which is in
the Program Group Accessories
2. Select View,
Scientific
97
4. Enter data on keypad
(Limit is 8 bits for Binary)
3. Enter initial
data type here
Dec = Decimal
Bin = Binary
98
49
6. Observe answer
5. Enter final
data type here,
observe results
Initial zeros are dropped,
so answer is 0001 0111
99
ADSL Example - 架站之應用
100
50
ADSL Example - 與視訊會議設備之結合
101
ADSL Example -無線上網之應用
102
51
ADSL Example - 與IP-VPN網路的搭配
103
Topics Covered
z
The First Bank of Paradise
z
Networked Applications
z
Packet switching and Multiplexing
z
LANs versus WANs
z
Within a site versus between sites
104
52
Elements of a Network
Message (Frame)
Application
Application
Client
Station
Switch
Server
Station
Switch
Access
Line
Switch
Mobile Client
Station
Trunk
Line
Trunk
Line
Switch
Outside
World
Router
Mobile Client
Station
105
Topics Covered
z
Internets
z
z
z
Package
(Packet)
Routers
Packets carried within frames
Truck
(frame)
Categories
z
Internets
z
The Internet: ISPs and NATs
z
Intranets
z
Extranets
106
53
Topics Covered
z
z
The Need
z
Legacy Networks
z
Scalability
z
Standards
z
Need for Efficiency
107
Topics Covered
z
Security
z
Firewalls
z
VPNs
z
Wireless Communication
108
54
Topics Covered
z
Quality of Service (QoS)
z
Numerical objectives that must be met
z
Speed and throughput
z
Latency
z
Response time
z
Availability
z
Error rate
109
Topics Covered: Pat Lee’s Home Network
6.
A1-BD-33-6E-C7-BB
2.
Cable
Modem
1.
Coaxial Cable
to ISP
3. UTP Cord
5. UTP
Cord
4.
Access
Router
7. File
Sharing
5. UTP
Cord
6.
B2-CD-13-5B-E4-65
PC in Study
8. Printer
Sharing
110
55
Topics Covered: Pat Lee’s Home Network
z
DHCP
z
NAT
z
DNS
111
56

Introduction

Transcription

Similar documents

Summer Work for Students Entering AP Calculus AB

COVER SHEET FOR THE CEMALA FOUNDATION GRANT PACKET

wooweb-pro v5

eCabinet Systems Software Expands and Diversifies

- Included with Park Millennium Cable TV Package

Router High-Flex Green Efficiency

Equipment List Brochure PDF - Integrated Wood Components

Instalation Guide

Freud test table

Dewalt DW618 Super-PID Conversion