Chapter 6
Data Communication and the
Cloud
Jason C. H. Chen, Ph.D.
Professor of MIS
School of Business Administration
Gonzaga University
Spokane, WA 99258
chen@jepson.gonzaga.edu
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GearUp Scenarios
Chapter 4: Hardware and Software
• GearUp has important decisions to make about
critical software development project
Chapter 5: Database Processing
• GearUp does not have the easy access to data
needed to analyze vendor quality and costs
Chapter 6: Data Communication and the Cloud
• GearUp needs to make decisions about building
infrastructure for the next stage of its growth
• GearUp needs to understand advantages and
disadvantages of cloud-based computing
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GearUp: “No, I Mean 25 Cents an Hour.”
• Gearup’s Web hosting costs rising rapidly
• Lucas suggests provisioning Web servers and
databases in the cloud
• Provision server resources by the hour
• Costs: $50/mo plus 25-cents per hour for
processing time used
• Could yield huge savings
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Topics in Networks
• Three popular networks
–
–
–
–
LAN
MAN
WAN and
Internet
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Study Questions
Q1: What is a computer network?
Q2: What are the components of a LAN?
Q3: What are the fundamental concepts you should
know about the Internet?
Q4: What processing occurs on a typical Web
server?
Q5: Why is the cloud the future for most
organizations?
Q6: How can organizations use the cloud?
Q7: 2022?
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Q1: What Is a Computer Network?
• Computer network is a collection of computers that
communicate with one another over a variety of transmission
lines.
• Three basic types of networks: LAN, WAN, and Internet.
• What are the alternatives for a WAN?(video)
Figure 6-1 Major Network Types
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Connecting to the Internet
What Are the Alternatives for a WAN?
• WANs connect computers located at physically
separated sites by obtaining connection capabilities
from a third-party, typically an Internet Service
Provider (ISP).
• Three primary functions of an ISP are to:
1. Provide users with a legitimate Internet address
2. Serve as a gateway for users to connect to the Internet
3. Help pay for the Internet by collecting money from
customers and using it to pay access fees and other
charges
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What is a computer network?
• Network: a communications, data exchange, and
resource-sharing system created by linking two or
more computers with communication standards, or
protocols, so that they can work together
• Three major types of networks:
– Local area network (LAN): computers connected at a
single physical location, such as networks on GU campus.
– Wide area network (WAN): Computers connected between
two or more separated sites (locations)
– The Internet and internets: Networks of networks
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What Is a Computer Network?
• Additional characteristics of networks:
 LAN communication lines reside on-premises, making
it easier for a business to locate a network wherever it
chooses.
 WAN communication lines are owned by a third-party
vendor. A business contracts with vendor to use its
WAN lines.
 Each type of network uses protocols which are sets of
rules that two devices use to communicate with each
other.
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Q2: What Are the Components of a LAN?
SOHO
LAN
Figure 6-2 Typical Small Office/Home Office (SOHO) LAN
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What Are the Components of a LAN?
• Components are usually located within a half mile of each
other.
• A switch is a special-purpose computer that receives and
transmits messages to computers in the LAN.
• A network interface card (NIC)
is a hardware component that
connects each device’s circuitry
to a cable allowing protocols to
send data across the LAN.
• Most computers today
include an NIC.
Fig 6 (extra): Local Area Network (LAN)
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What are the components of a LAN?
A media access control
(MAC) address serves as a
unique identifier for each
NIC on a LAN.
Fig 6 (extra): Local Area Network (LAN)
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Wired Connectivity:
What Are the Components of a LAN?
• Media access control (MAC) address serves as a unique identifier
for each NIC on a LAN.
• Unshielded twisted pair (UTP) cables, shown on left, are one way
to connect devices to a LAN.
• Optical fiber cables, shown on right, connect devices to a LAN
using fiberglass wires to transmit signals which are light rays.
Cladding contain the signals. Optical fiber carries more traffic
than UTP cables.
Fig 6-(extra) Unshielded Twisted Pair (UTP) Cable
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Fig 6-5 Optical Fiber Cable
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Question
• In order for a printer or laptop to connect to
a wireless LAN they must have a(n)
– NIC or
– Something else?
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Wireless Connections:
What Are the Components of a LAN?
• IEEE 802.11 wireless
protocol uses wireless NICs
(WNIC) to connect devices to
networks similar to how
wired NICs operate.
• Figure depicts a combination
of NICs and WNICs on a
LAN.
• Access points (AP) use
802.3 protocol to
communicate with a switch
and 802.11 protocol to send
and receive wireless traffic.
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Fig Extra: LAN with Wireless
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LAN Protocol
IEEE 802.3
• Wired LAN
• 10/100/1000 Mbps
• Ethernet
IEEEE 802.11
• Wireless LAN
• 802.11n
• Bluetooth
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What Are the Components of a LAN?
• The IEEE, Institute for Electrical & Electronics Engineers,
is a committee that creates and publishes protocols and
standards used by virtually every network.
• IEEE 802.3, or Ethernet, protocol is used by all LAN
devices. It specifies hardware characteristics and describes
how messages are packaged and processed.
• Onboard NICs in new PCs support10/100/1000 Ethernet
protocol which describes transmission rate speed.
• Communication speeds are expressed in bits like
1,000,000 for megabits.
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Summary of LAN and WAN Networks
Figure 6-3 Network Technology Summary
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Connecting to the Internet
• Connecting personal computers to an ISP requires that digital
signals coming out of the computer are converted to analog
signals. Analog signals coming into a personal computer must
be converted to digital signals.
Comparison of digital and analog signals.
digital signal (0/1)
analog signal (wavy)
Fig 6-4 Analog Versus Digital Signals
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What are the alternatives for a WAN?

Modems are used to convert the signals back and forth as
shown in the figure below.
digital signal
analog signal
Fig 6-5 Personal Computer Internet Access
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Two Ways connecting to an ISP
(for Homes and Small Businesses)
• 1. DSL (Digital Subscriber Line) modem shares a single
communication line for a telephone and a personal computer. It’s
much faster than a dial-up modem and allows a user to maintain a
constant network connection with an ISP.
 Asymmetric DSL, ADSL, provides different upload/download speeds.
 Symmetrical DSL, SDSL, provides the same upload/download speeds.
• 2. Cable modem shares a single communication line for cable TV
and a personal computer. It’s also faster than a dial-up modem and
allows users to maintain a constant network connection.
 Because cable modems use a neighborhood distribution center,
transmission speeds vary based on the number of network users.
• DSL and cable modems are considered broadband because their
transmission speeds exceed 256 kbps (narrowband is with the
transmission speeds of less than 56kbps).
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Q3: What Are the Fundamental Concepts
You Should Know About the Internet?
Fig 6-6 Using the Internet for a Hotel Reservation
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Video
• Cloud_Computing_bmis235(4m50s)
• TCP / IP - An animated discussion (6:12)
• http://www.youtube.com/watch?v=RbY8Hb6abbg
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What are the functions of the five TCP/IP?
• Throughout this chapter, and while you’re using
the Internet, you’ll hear these terms used
frequently.
– Architecture is the arrangement of protocol layers with
each given specific tasks.
– Protocols are sets of rules that accomplish tasks in each
layer.
– Programs are specific computer products that
implement protocols.
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Five Layers of TCP/IP Protocols
Application Layer
USERS?
Transport (TCP) Layer
Software
Developers
Internet Protocol (IP) Layer
Five
Layers of
TCP/IP
Why
Protocols
TCP/IP
Protocol?
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Hardware
Experts
Data Link Layer
Physical Layer
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TCP/IP Protocol Architecture




This chart gives you
the specific and
broad functions of
each layer in the
TCP/IP-OSI
architecture.
TCP or Transmission
Control Protocol
• Breaks traffic up
into packets and
sends each one
along its way
IP (Internet Protocol)
Routers
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Fig 6-7 TCP/IP Protocol Architecture
TCP and IP Protocols:
Middle Layers
• TCP or Transmission Control Protocol
• Breaks traffic up into packets and sends each
one along its way
• IP (Internet Protocol)
• Routers
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IP Addressing
• Public IP Addresses
• Identify a particular device on public Internet
• Public IP addresses must be unique, worldwide
• Assignment controlled by ICANN (Internet Corporation for
Assigned Names and Numbers)
• Private IP Addresses
• Identify a particular device on a private network
• Controlled by company operating network
• Major benefits
1. Public IP: All devices on LAN share a public IP address.
2. Private IP address, need not register computer with ICANNapproved agencies.
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Functions of the LAN Device
• Switch processing: IEEE 802.3 wired LAN traffic
• Access-point processing: IEEE 802.11 wireless LAN
traffic
• Translating between IEEE 802.3 and IEEE 802.11
• Converting between Analog and Digital
• Assigning private IP addresses
• Converting IP address between private and public IP
addresses
• Routing packets
• And more …
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Public IP Addresses and Domain Names
IPv4
• Four decimal dotted notation like 165.193.123.253
Domain name
• Worldwide-unique name affiliated with a public
IP address
• Affiliation of domain names with IP addresses
is dynamic
URL (Uniform Resource Locator)
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Virtual Private Networks (VPN)
• Virtual Private Networks (VPNs) create the appearance
of private point-to-point connections by using tunnels to
create virtual, private pathways over the Internet.
• Figure below shows connections a VPN uses.
Fig 6-9 Remote Access Using VPN: Actual Connections
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Why Do Organizations Use Virtual Private
Networks?


A VPN appears to be a direct connection between two sites
as shown in this figure.
Software encrypts data as they pass through the VPN making
them more secure. Then, decodes when user receives them.
Fig 6-10 Remote Access Using VPN: Apparent Connection
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Why Do Organizations Use Virtual Private
Networks?

This figure shows how a WAN uses three different VPN
tunnels to connect geographically separated users.
Secure but costly !!!
One Solution: Web Server
Fig 6-11 WAN Using VPN
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Q4: What Processing Occurs on a
Typical Web Server?
• Almost all e-commerce applications use the threetier architecture, which is an arrangement of user
computers and servers into three categories, or tiers
(see Fig. 6-13).
– User tier:
 consists of computers, phones, and other devices that have
browsers that request and process web pages.
– Server tier:
 consists of computers that run Web servers and process
application programs.
– Database tier:
 consists of computers that run a DBMS that processes requests
to retrieve and store data.
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Three Tier Architecture for E-Commerce Applications
Fig 6-13 Three Tier Architecture
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DATABASE TRENDS
Linking Internal Databases to the Web
User tier
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Database tier
Server tier
N
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Web-Based Client/Server Database Architecture
2. Request for
data-based Web page
1. Request for
data-based Web page
Network
8. Data-based
Web page
Web Browser
3. Data query
6. Retrieved data
7. Data-based
Web page
4. Data
query
Web server
5. Retrieved
data
Legend
Communications
Between Web browser
And Web server
Database Server
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Communications
Between Web server
And database server
Watch the Three Tiers in Action!
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Fig 6-12
Hypertext Markup Language (HTML)
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Fig 6-15
XML, Flash, Silverlight, HTML 5
• XML (eXtensible Markup Language)
• Fixes several HTML deficiencies
• Program-to-program interaction over Web
• Flash
• Browser add-on for animation, movies, and other
advanced graphics inside a browser.
• Silverlight
• Browser add-on with greater functionality than
Flash
• HTML 5.0
• Supports animation, movies, and graphics
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Q5. Why Is the Cloud the Future for Most
Organizations?
• Cloud
 Elastic leasing of pooled computer resources
over the Internet
• Elastic
 Dynamically increasing/decreasing a leased
resource programmatically in a short span of
time, and only pay for resource used
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Why Is the Cloud Preferred to In-House Hosting?
Fig 6-17 Comparison of Cloud and On-Site Alternatives
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Why Is the Cloud Preferred to In-House Hosting? (cont’d)
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Fig 6-17 Comparison of Cloud and On-Site Alternatives
When Does the Cloud Not Make Sense?
• Only when law or industry standard
practices require physical control over the
data
• Private cloud
 In-house hosting, delivered via Web service
standards
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Clouds
• Cloud computing
 Refers to a computing network on the Internet
 When you access a video from a site like
Facebook, you are accessing computing
services in the cloud. You don’t know which
server is processing your Facebook requests or
which server is playing the video. You just
know that somewhere in the cloud one or more
servers are causing the video to be downloaded
to your computer.
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Cloud Service
• Web Email
• Online virus
detection
• YouTube
• Online Doc
• Blogging
•…
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Another Video for Cloud Computing
http://www.salesforce.com/cloudcomputing/?fromSearch=true
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Q6. How Can Organizations Use the Cloud?
Fig 6-18 Three Fundamental Cloud Types
T/F: The most basic cloud offering is platform as a service (PaaS),
which is the cloud hosting of a bare server computer or disk drive.
Answer:
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See page. 201
Q7: 2022?
Cloud computing benefit
• Individuals on iCloud
• Small groups using Office 365
• Startups Using PaaS
• Huge organizations using IaaS
New categories of products and services
Create new jobs?
Tele-action
• Telediagnosis, telesurgery, telelaw enforcement
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• End of Chapter 6
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