Data Communication and the

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Oct 26, 2013 (3 years and 10 months ago)

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Dr. Chen,
Management Information Systems

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

Dr. Chen,
Management Information Systems

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


2

Dr. Chen,
Management Information Systems

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

Dr. Chen,
Management Information Systems

Topics in Networks


Three popular networks


LAN


MAN


WAN and


Internet

Dr. Chen,
Management Information Systems

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?

Dr. Chen,
Management Information Systems


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

6

Q1: What Is a Computer Network?

Dr. Chen,
Management Information Systems


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

Connecting to the
Internet

What Are the Alternatives for a WAN?

7

Dr. Chen,
Management Information Systems

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

Dr. Chen,
Management Information Systems


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.

What Is a Computer Network?

9

Dr. Chen,
Management Information Systems

Q2: What Are the Components of a LAN?


SOHO
LAN

Figure
6
-
2 Typical Small Office/Home Office (SOHO) LAN

Dr. Chen,
Management Information Systems


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
.

What Are the Components of a LAN?

Fig
6 (extra):
Local Area Network (LAN)

11

Dr. Chen,
Management Information Systems

Fig
6 (extra): Local
Area Network (LAN)

What are the components of a LAN?

A
media access control
(
MAC
) address serves as a
unique identifier for each
NIC on a LAN.

Dr. Chen,
Management Information Systems


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.


Wired Connectivity:

What Are the Components of a LAN?

Fig
6
-
(extra)
Unshielded Twisted Pair (UTP) Cable

Fig 6
-
5 Optical Fiber Cable

13

Dr. Chen,
Management Information Systems

LAN Protocol

IEEE 802.3


Wired
LAN


10/100/1000
Mbps



Ethernet

IEEEE 802.11


Wireless LAN


802.11n


Bluetooth


Dr. Chen,
Management Information Systems


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.

What Are the Components of a LAN?

15

Dr. Chen,
Management Information Systems

Summary of LAN and WAN Networks

Figure
6
-
3 Network Technology Summary

Dr. Chen,
Management Information Systems


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.


Connecting to the Internet

Fig
6
-
4
Analog Versus Digital Signals

17

digital signal (0/1)

analog signal (wavy)

Dr. Chen,
Management Information Systems

What are the alternatives for a WAN?

Fig 6
-
5 Personal Computer Internet Access


Modems are used to convert the signals back and forth as
shown in the figure below.


18

digital signal

analog signal

Dr. Chen,
Management Information Systems


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).

Two Ways connecting to an ISP

(for Homes and Small Businesses)

19

Dr. Chen,
Management Information Systems

Q3: What Are the Fundamental Concepts
You Should Know About the Internet?

Fig 6
-
6 Using the Internet for a Hotel Reservation

Dr. Chen,
Management Information Systems

Video


Cloud_Computing_bmis235(4m50s)



TCP / IP
-

An animated discussion (6:12)



http://www.youtube.com/watch?v=RbY8Hb6abbg


21

Dr. Chen,
Management Information Systems

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.

Dr. Chen,
Management Information Systems

Five Layers of TCP/IP Protocols

Five

Layers of

TCP/IP

Protocols

Application Layer

Transport (TCP) Layer

Internet Protocol (IP) Layer

Physical Layer

Software
Developers

Hardware

Experts

23

USERS?

Data Link Layer

Why
TCP/IP
Protocol
?


Dr. Chen,
Management Information Systems

TCP/IP Protocol Architecture

Fig 6
-
7
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

Dr. Chen,
Management Information Systems

TCP and IP Protocols
:

M
i
dd
l
e

Layers


TCP or Transmission Control Protocol


Breaks traffic up into packets and sends each
one along its way


IP (Internet Protocol)


Routers


Dr. Chen,
Management Information Systems

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 ICANN
-
approved agencies.

Dr. Chen,
Management Information Systems

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


R
outing packets


And more …

Dr. Chen,
Management Information Systems

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


A
ffiliation
of domain
names with
IP addresses
is
dynamic

URL (Uniform Resource Locator)

Dr. Chen,
Management Information Systems


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.

Virtual Private Networks (VPN)

Fig
6
-
9
Remote Access Using VPN: Actual Connections

29

Dr. Chen,
Management Information Systems

Fig 6
-
10 Remote Access Using VPN: Apparent Connection

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.

30

Dr. Chen,
Management Information Systems

Fig 6
-
11 WAN Using VPN

Why Do Organizations Use Virtual Private
Networks?


This figure shows how a WAN uses three different VPN
tunnels to connect geographically separated users.

31


Secure but costly !!!

Dr. Chen,
Management Information Systems

Q4: What Processing Occurs on a
Typical Web Server?


Almost all e
-
commerce applications use the three
-
tier 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
:


c
onsists of computers that run Web servers and process
application programs.


Database tier
:


c
onsists of computers that run a DBMS that processes requests
to retrieve and store data.

Dr. Chen,
Management Information Systems

Fig 6
-
13 Three Tier Architecture

Three Tier Architecture for E
-
Commerce Applications

Dr. Chen,
Management Information Systems

Linking Internal Databases to the Web

DATABASE TRENDS

N

34

Server t
i
er

Database t
i
er

U
ser t
i
er

Dr. Chen,
Management Information Systems

Web
-
Based Client/Server Database Architecture

Network

Web server

Database Server

Web Browser

5. Retrieved


data

4. Data


query

7. Data
-
based


Web page

8. Data
-
based


Web page

1. Request for


data
-
based Web page

6. Retrieved data

3. Data query

2. Request for


data
-
based Web page


Legend

Communications

Between Web browser

And Web server


Communications

Between Web server

And database server

Dr. Chen,
Management Information Systems

Watch the Three Tiers in Action!

Fig 6
-
12

Dr. Chen,
Management Information Systems

Hypertext Markup Language (HTML)

Fig 6
-
15

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Management Information Systems

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

Dr. Chen,
Management Information Systems

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

Dr. Chen,
Management Information Systems

Why Is the Cloud Preferred to In
-
House Hosting?

Fig 6
-
17 Comparison of Cloud and On
-
Site Alternatives

Dr. Chen,
Management Information Systems

Why Is the Cloud Preferred to In
-
House Hosting
? (cont’d)

Fig 6
-
17 Comparison of Cloud and On
-
Site Alternatives

Dr. Chen,
Management Information Systems

When Does the Cloud Not Make Sense?


Only when law or industry standard
practices require physical
control over
the
data


P
rivate cloud


In
-
house
hosting, delivered via
Web
service
standards

Dr. Chen,
Management Information Systems


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.


Clouds

Dr. Chen,
Management Information Systems

44

Cloud Service


Web Email


Online virus
detection


YouTube


Online Doc


Blogging




Dr. Chen,
Management Information Systems

Dr. Chen,
Management Information Systems

Another Video for Cloud Computing

http://www.salesforce.com/cloudcomputing/?fromSearch=true

46

Dr. Chen,
Management Information Systems

Q6. How Can Organizations Use the
Cloud?

Fig 6
-
18 Three Fundamental Cloud Types

Dr. Chen,
Management Information Systems

Q7: 2022?

Cloud computing benefit


I
ndividuals
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



Dr. Chen,
Management Information Systems


End of Chapter 6