Download Welcome to the Cloud - Joseph H. Schuessler, PhD

o and Panko
ness Data Networks and Security, 9th Edition
earson
Chapter 1
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Today, we are surrounded by networks.
This book will help you learn the skills you
will need to participate in this networking
revolution.
This chapter introduces basic network
concepts and issues you will use
throughout the book.
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Difficult Material
Central Concept (CEPT)
Take it slowly, step by
step.
This will require some
extra work.
This is a central concept
(CEPT) you need to
understand really well.
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Into the Cloud
Basic Network Concepts
Packet Switching
Internetworking
Layers
Internet Standards
A Small Home Network
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Works at the First Bank of Paradise (FBP) in
Hawai`i
Develops new media marketing campaigns
using Facebook, YouTube, e-mail lists, and
the bank’s website
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Current project is the AlohaSmart credit
card smartcard
◦ Smartcards have chips as well as mag stripes
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In the morning, opens his tablet to check
e-mail containing remarks about his
PowerPoint marketing plan
Turns on his desktop computer and reworks
the PowerPoint presentation
Automatically uploaded “to the cloud” with
BlueSynch
Later available to his work notebook and to
meeting participants
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The cloud imagery indicates that the user does not have to
understand how systems “inside the cloud” operate.
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PowerPoint is installed on his desktop
computer at home.
For his work notebook computer and on his
tablet, PowerPoint is stored in the cloud.
◦ He downloads it when he needs it.
◦ Pays for it by the month, as a service.
◦ It is called software as a service (SaaS).
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On the FBP networking staff
Manages the headquarters building wireless
LANs
Walks around doing readings with her
sniffer program
Learns information about access points,
their signal power, and their security
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SSID
FBP
A1-B2-C3D4-E5-F6
FBP
FBP
BB-D5-33-D4- 19-FF-AE-D46B-DD
EC-63
Signal
-85 dBm
-60 dBm
-60 dBm
Mode
802.11g
802.11n
802.11n
Channel
11
48
44
Encryption
AES-CCMP
AES-CCMP
AES-CCMP
Authentication
WPA2/PEAP
WPA2/PEAP
WPA2/PEAP
Vendor
Cisco
Cisco
Cisco
BSSID
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Currently, must walk around at least daily.
◦ Even then, cannot find intermittent problems.
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FBP is installing a centralized wireless
management system.
◦ Will be able to manage all access points centrally.
◦ She can constantly monitor the network for
problems.
◦ The network will alert her to problems.
◦ The system can even make adjustments
automatically.
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In charge of wireless security at FBP
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BYOD (Bring Your Own Device) Problem
◦ Number of smartphones and tablets is exploding
◦ Owned by the employees but used partially for
business purposes
◦ Great diversity in smartphone and tablet
operating systems
◦ Device security is improving but limited
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Claire Lorek found a rogue access point in
one of her walkarounds.
She and John Lee visited Albert Gomes who
installed the unauthorized access point.
Albert thought that the access point was
secure in stealth mode.
However, Claire’s and hackers’ software
could find it.
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Rather than punish Albert Gomes, they
worked to help him.
His department did need more capacity.
Claire would install another access point,
one with strong security.
John and Claire had developed an ally.
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Into the Cloud
Basic Network Concepts
Packet Switching
Internetworking
Layers
Internet Standards
A Small Home Network
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Working Definition
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The client and the server share processing work.
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P2P Processing can be done without a
network (as shown) or with a network.
No servers are needed.
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Transmission Speed Measurements
Bits per second (bps)
Usually not bytes per second (Bps)
Metric Suffixes
Kilobits per
second
kbps (lowercase k)
1,000 bits per second
(not 1,024)
Megabits per
second
Mbps
1,000 kbps
Gigabits per
second
Gbps
1,000 Mbps
Terabits per
second
Tbps
1,000 Gbps
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File Downloads
100
1
kbps Mbps
E-mail message
(250 words)
.15 s
Photograph (5
MB)
1 Hr HTDV Video
(10 Mbps)
Backup Synch
(10 GB)
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5
Mbps
10
Mbps
100 1 Gbps
Mbps
0s
0s
0s
0s
0s
8m
1m
10 s
5s
1s
0.1 s
4d
10 h
2h
1h
6m
36 s
12 d
28 h
6h
3h
17 m
2m
26
Live or
Streaming
Media
MP3 Song (10
kbps)
Standard Quality
TV (2 Mbps)
HDTV (10 Mbps)
Three HDTV
Channels
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100
1
kbps Mbps
OK
OK
5
Mbps
10
Mbps
100 1 Gbps
Mbps
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
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Into the Cloud
Basic Network Concepts
Packet Switching
Internetworking
Layers
Internet Standards
A Small Home Network
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Each switch along the way forwards the
packet out a port to another switch (or to
the destination host).
Individual packet switches have no
knowledge of the entire path taken by the
packet.
We will see how this works in detail in later
chapters.
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
Forerunner of the Internet
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Funded by Larry Roberts at the Advanced
Research Projects Agency (ARPA)
◦ Now the Defense Advanced Research Projects Agency
(DARPA)
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To explore packet switching

To give researchers access to ARPA-funded
software on host computers in distant cities
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First four nodes began operation in 1969
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Into the Cloud
Basic Network Concepts
Packet Switching
Internetworking
Layers
Internet Standards
A Small Home Network
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Bob Kahn at DARPA needed a way for researchers
on one network to use resources on another
network.
Packets would have to travel across multiple
networks.
Kahn and Vint Cerf came up with the idea of
connecting multiple networks by devices called
routers.
◦ The original name was gateways.
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Generically, networks of networks are internets.
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Kahn created the global Internet (Capital I).
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Capitalization of “internet”
◦ With an uppercase “I,” Internet means the global
Internet we use every day.
◦ With a lowercase “i”, internet means any internet
or the internet layer.
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Basically, Kahn and Cerf created a second layer
of networking on top of single networks.
This required the creation of a parallel set of
concepts for single networks and internets.
Single networks and internets use similar
concepts but give these concepts different
names.
It is important for you to get this clear in your
head.
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Component
Generic
Terminology
Addresses
Single
Networks
Internets
Vary by
network
technology
32-bit IPv4
Addresses
and 128-bit
IPv6
Addresses
Packets are called
Packets
Frames
Packets
Packet switches are
called
Switches
Switches
Routers
Data links
Routes
End-to-end routes
are called
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Component
Generic
Terminology
Addresses
Single
Networks
Internets
Vary by
network
technology
32-bit IPv4
Addresses
and 128-bit
IPv6
Addresses
Packets are called
Packets
Frames
Packets
Packet switches are
called
Switches
Switches
Routers
Data links
Routes
End-to-end routes
are called
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Into the Cloud
Basic Network Concepts
Packet Switching
Internetworking
Layers
Internet Standards
A Small Home Network
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Networks can be described at several layers
of detail.
Each layer provides services to the layer
above it.
◦ The road provides service to the car tires.
◦ The car tires provide service to the car.
◦ The car provides service to the driver.
◦ A commercial driver provides service to the goods
being delivered.
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2.
The data link is the packet’s
path through the network
In this case: X-A-B-D-F-Y
1.
Physical links are
connections between
adjacent pairs of devices
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How many data links does the
packet pass through?
How many physical links does
the packet pass through?
Name them.
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Formed by graduate students to create
standards for the ARPANET.
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Called their standards Requests for Comment
(RFCs).
◦ Did not feel that they had the authority to create
standards, so they used the weaker term RFC.
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The NWG evolved into today’s standards body
for the Internet, the Internet Engineering Task
Force (IETF).
Internet standards today are still called RFCs.
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Basically, Kahn and Cerf created a second layer
of networking on top of single networks.
This required the creation of a parallel set of
concepts for single networks and internets.
Single networks and internets use similar
concepts but give these concepts different
names.
It is important for you to get this clear in your
head.
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Dashed line shows
the path of a packet
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Physical links connect
adjacent devices,
as noted earlier.
How many
physical links are there
between the two hosts?
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A data link is the path of a
frame through a single
network, as noted earlier.
There is one data link per network.
How many data links are in the figure?
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A route is a packet’s path
through an internet.
Added for internets.
How many routes are there in the figure?
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Host P transmits a packet to Host Q.
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There are seven networks between the hosts.
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1. How many packets will there be along the way?
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2. How many frames will there be along the way?
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3. How many routes will there be along the way?
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4. How many data links will there be along the way?
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Layer Name
Broad Purpose Specific Purpose
5
Application
4
3
2
1
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Transport
Internet
Data Link
Physical
Singlenetwork
transmission
(switched or
wireless)
Connection across a
single network, Frame
formats and switch
operation
Physical connections
between adjacent
devices
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Layer Name
Broad Purpose Specific Purpose
5
Application
4
Transport
3
Internet
2
1
Data Link
Physical
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Internet
Transmission
Application message
fragmentation, error
correction, congestion
reduction, etc.
Transmission of
packet across an
internet, Packet
formats, router
operation
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Number Name
Broad Purpose
Specific Purpose
5
Application Communication Same
between
applications
4
Transport
3
Internet
2
Data Link
1
Physical
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Into the Cloud
Basic Network Concepts
Packet Switching
Internetworking
Layers
Internet Standards
A Small Home Network
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IP
◦ Internet layer protocol
◦ Unreliable best-effort internet layer operation
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TCP
◦ Transport layer protocol
◦ TCP messages are called segments
◦ Provides transport layer functionality to fix
problems
◦ Error correction, and so on
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UDP
◦ The other transport layer protocol
◦ Messages are called datagrams
◦ Unreliable, so used when reliability is not desired
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Layer
Transport Layer
Internet Layer
Standard(s)
Transmission
User Datagram
Control Protocol
Protocol (UDP)
(TCP)
No Fragmentation
Fragmentation
No Error Correction
Error Correction
No Congestion
Congestion control
Control
Internet Protocol (IP)
IPv4 and IPv6
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1977
◦ First experimental connection of three networks
◦ (Two wireless and the ARPANET)
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1980s
◦ Internet opened to outside network for e-mail
exchanges
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TCP/IP standards evolved in the 1980s
◦ Hosts could run either TCP/IP or NCP standards.
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1983
◦ All hosts were required to run TCP/IP.
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NSFNET
◦ In the 1980s, the NSFNET funded by NSF was the
core of the Internet.
◦ NSF had an Acceptable Use Policy barring
commercial activity such as e-commerce.
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1995
◦ NSFNET replaced by commercial ISPs.
◦ E-commerce was no longer forbidden.
◦ The e-commerce revolution began.
◦ The World Wide Web became popular just before
that.
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To use the Internet,
you need an Internet
service provider and
an access line to
your ISP.
Your ISP gives you
access and carries
your packets.
Organizations also
need ISPs.
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ISPs collectively comprise the Internet backbone.
They interconnect at Network Access Points (NAPs)
to exchange packets.
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Trace the path packets take from the User PC to the Webserver.
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IP, TCP, and UDP are standards for delivery
packets.
TCP/IP also has supervisory protocols:
◦ To handle things beyond packet delivery.
◦ Managing IP addresses.
◦ Error handling, and so on.
◦ We will look at two supervisory protocols in this
chapter.
◦ We will look at many more in Chapter 10.
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Into the Cloud
Basic Network Concepts
Packet Switching
Internetworking
Layers
Internet Standard
A Small Home Network
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The IP gives the home one IP address.
The home network has multiple devices that need IP addresses.
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The access router DHCP circuit gives
private IP addresses to other devices.
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NAT allows multiple internal hosts to share a single
external IP address.
External sniffers cannot learn internal addresses.
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Into the Cloud
Basic Network Concepts
Packet Switching
Internetworking
Layers
Internet Standard
A Small Home Network
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
This is the first of four introductory
chapters.
◦ The others deal with standards, security, and
network and security management.

Chapter 1 introduces basic network
concepts and issues.
◦ Presented historically because some aspects of
networking only make sense if you understand
the development of internetworking.
◦ Specifically, single-network versus internet
concepts and terminology (two of everything).
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Chapter 2 looks at standards in more depth.
◦ It will look at major characteristics of standards,
such as the syntax of messages.
◦ It will focus on the data link, internet, transport,
and application layers, which work by sending
structured messages.
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