Transcript ISM 3410 Telecomm and Networking in Business

Lecture 01
• We begin our lecture to ask ourselves a few
simple questions for this subject such as:
– Have you used telecommunications?
(to p2)
• Examples!
– How do define “telecommunications”?
(to p13)
– why do we need it for?
– can we survive without it?
(to p9)
(to p14)
• Different modes of telecomm applications!
(to p28)
• The concept of convergence
(to p15)
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Examples of
TelecommunicationApplications
1) telephone, mobile phone Figure 1-5
2) use of Internet, web browser Figure 1-6
3) airline reservation systems
(to p3)
(to p4)
- with combination of applications such as dial(to p5)
up line as shown in Figures 1-7 & 1.8
(to p7)
4) ATM, Octopus Figure 1-9
5) automated remote water meter reading
Figure 1-10
(to p8)
(to p1)
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FIGURE 1-5
Simplified diagram of the components of a standard telephone call.
(a simple version)
(Note: we will learn more on how a telephone company works in the later lecture!) (to p2)
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FIGURE 1-6
The telecommunications between a home computer and an Internet access provider.
A version of dial-up service via telephone co
Question: How does it differ, say, if you have subscripted a broadband service in HK?
(to p2)
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FIGURE 1-7
The telecommunications connections between a traveler and an airline reservation computer through a local area network.
Note: This dial-up approach still applied to most travel agents in HK, however
its structure has changed substantially in this Internet age. How and why?
(to p6)
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More example
.
FIGURE 1-8
The telecommunications connection between a traveler and an airline reservation computer through a leased line.
Another version of dial-up application but -This special line will provide a high speed and secure of
Information retrieval.
(to p2)
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FIGURE 1-9
An ATM connected to a computer by a telecommunications line.
Note: This is a simple
version of ATM
Question: What competitiveness has this application received ?
How does ATM work in HK?
(to p2)
7
.
FIGURE 1-10 Remote reading of a water meter using telecommunications.
Electricity
Question: What adv has this application brought to Businesses?
Can it applied to all cities over the world?
(to p2)
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reserved.
Telecommunications and
Networking
• What is Telecommunications?
– Tele– Communications
– Telecommunications
(to p10)
(to p11)
(to p12)
(to p1)
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Definitions
• Tele– means by distance or distance apart
(to p9)
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Definitions
• communications
– information pass from one place to another
(to p9)
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Definitions
• Telecom refers as comm between parties
over a distance through electrical or
electromagnetic means (conventionally!)
• (note: we will spend more time to discuss more to
understand what does it meant for through e means)
(to p9)
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Why do we need
Telecommunications?
1) merging of IS and networking to transmit
information for business competitive power
2) obtaining information at the right place at a right
time, eg digital phone to acquire local temperature
3) allowing geographic dispersion of facilities and
people, such as telecommuting and e-commerce
4) allowing on-line marketing such as airline
ticketing systems so that selling products can
(to p1)
conduct directly, eg eBay, TaoBao (espeicall on Nov 11 in China)
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-
Answer!
Yes:
If you like to live in a primitive form
of a life style
No:
If you live in an modern society or an
(to p57)
Informative world
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(to p1)
Way to classifying
telecommunication applications
• Consider Figure shown in the slide 16, we
can classify each of these applications by
their:
(to p17)
– geography
– Mode of connection
(to p23)
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(to p1)
(to p15)
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geography
•
•
•
•
•
(to p18)
Local area network (LAN)
Metropolitan area network (MAN)
(to p20)
Wide area network (WAN)
(to p61)
Backbone
(to p22)
Personal Area Network
(to p19)
(to p15)
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Local area network (LAN)
(device used to share resource between
PCs in a Lab)
(device used to connect LANs together)
It composes of nodes
And communication
links
Server
(to p17)
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Metropolitan area network (MAN)
(to p15)
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Wide area network (WAN)
– covers a large geographic area and uses circuits
provided by a common carrier
– many made up of a combination of switched or
leased, terrestrial and satellite, and private
microwave circuits
– typically span hundreds or thousands of miles
and provide data transmission rates from
64Kpbs to 2Gpbs
(to p21)
– Semantic view
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(to p15)
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Personal Area Network
A network of a few meters, interconnecting wireless devices such as PDA,
Laptops, and other devices
(to p15)
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Modes of connection
• Fixed line connection
• Wireless connection
(to p24)
(to p25)
• Question: which mode should be acquired?
And why?
– Examples: home devices pic1, pic2, pic3
(to p61)
(to p62)
(to p63)
• Question: how to evaluate each of them
above?
(to p15)
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Fixed line connection
• Example:
(to p23)
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Wireless connection
• Wireless telephone connections
• Satellite and microwave connection
(to p26)
(to p27)
(to p23)
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Wireless telephone connections
(to p25)
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Satellite and microwave connection
(to p25)
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Convergence of technologies
• Convergence, which refers to coming together of
two areas or two companies, is happening at all
levels in telecomm:
– Products (local phone company Vs other phones in
market such as BO; USB devices )
– Companies (IBM and Apple for PC or notebooks)
– Technologies (fixed line vs Bluetooth or wireless)
(to p29)
• How to connect them together?
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Network Architecture
• A reference model that describes the layers of
hardware and software necessary to transmit data
between two points or for multiple devices /
applications to interoperate
• Reference models are necessary to increase
likelihood that different components from
different manufacturers will converse
• Two models to learn: OSI model and TCP/IP
(to p30)
protocol suite
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Standard models
• OSI
(to p31)
(to p48)
– Compatibility
•
•
•
•
(to p49)
TCP/IP
(to p51)
Others
(to p60)
Mobile network
Concept of logical and physical connections
(to p52)
in action
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OSI
– a worldwide organization known as ISO (International Standard Organization)
established rules and standards to oversee all these issues for vendors whose wish
to develop their products
– In 1978, ISO proposed a telecomm architecture called:
– Open System Interconnection (OSI)
– The ISO-OSI model
– the purpose of this model is to allow information/data interchange between
different brands of devices
– provides a basis for interconnecting dissimilar system/devices
– How it works
(to p32)
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ISO/OSI Model (cont.)
• OSI uses an architecture of layer approach
(a total of 7 layers) to represent the
components of the total process of
(to p32)
communication
• (See Figure 3.2, p91)
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(to p44)
Level 1: Physical connection
Levels 2-7: Logical connection
(exist in the software only)
(to p42)
(to p41)
(to p39)
(to p37)
(to p35)
(to p34)
(to p30)
Semantic view of their functions
(to p47)
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Layer 1: Physical link control
layer
• Layer 1: Physical link control layer
– connectivity on physical linkage
– allow bit streams from a device to flow onto the
network
– defines the electrical standards and signaling,
that is how connections could be established
and terminated
– the only layer in which data transmission
between devices takes place
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(to p33)
Layer 2:
Data link control
layer
• Layer 2: Data link control layer
– defines standards for structured data into
frames and sending frames across the network
– it answers questions such as
•
•
•
•
1. Where a frame starts or ends
2. How errors are detected and corrected
3. How to handle polling and addressing
4. How machines are addressed
(to p36)
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Layer 2:
Data link control
layer
• Layer 2 (cont.)
– it requires to work closely to devices such as
modem/FEP
– it controls the situation when data is received
from the circuit faster than the receiver can
handle it (it will slow down the transmission
until further notice … this process is known as
pacing)
– note: IEEE fully subscribes to OIS architecture
for the 802 standards for LANs
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(to p33)
Layer 3: Network control layer
• Layer 3: Network control layer
– primary functions are network addressing and
routing
– generates acknowledgements that an entire
message has been received correctly
– responsible to break down messages end from
layer 4 that suit for data transmission
(to p38)
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Layer 3: Network control
layer(cont.)
• Layer 3 (cont.)
– it decides which communication circuit to
transmit data
– it assembles data from blocks of bits before
passing them up the level 4
(to p33)
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Layer 4: Transport control layer
• Layer 4: Transport control layer
– selects the route (if more than one is availble)
the transmission will take between two devices
– converts user addressing that is meaningful to
network software and hardware
– controls the flow of messages so that it will not
over/under run of the speed of other devices
– prevents the loss or duplication of entire
messages (Note: Layer 2 is for frames)
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(to p40)
Layer 4: Transport control layer
(cont.)
• Layer 4 (cont.)
– multiplexing several streams of messages from
higher levels onto one physical circuit and
adding appropriate headers to messages to be
transmitted to recipients
– eg. Operators sends computer down time to all
users in one command
(to p33)
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Layer 5: Session control layer
• Layer 5: Session control layer
– temporary connection between
machines/programs for exchange of messages
– maintains and breaks a session between two
systems/users
– assign and control of priority to access and
passing message to the systems (such as icq
icon)
(to p33)
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Layer 6: Presentation layer
• Layer 6: Presentation layer
– deals with the way data is formatted and
presented to the users at the terminal
– performs constant format for data transmission
so that lower level would understand it
– software perform data transformation to meet
users’ need (such as different font size,
characters per line etc.)
(to p43)
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Layer 6: Presentation layer (cont.)
• Layer 6 (cont.)
– perform code conversion, data compaction, and
data encryption
– except data encryption, most aforementioned
tasks are done by software in the host computer
(to p33)
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Layer 7: Application or user layer
• Layer 7: Application or user layer
– is the ultimate end or data transmitted within
the network
– consists of application programs, and performs
the communicating commands such as data
editing, file editing etc
– performs the following 6 major functions
• 1. Common application service element (CASE),
that is define standard events such as logon,
password id.
(to p45)
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Layer 7: Application or user
layer(cont.)
• Layer 7 (cont.)
• 2. Job transfer and manipulation (JTM), defines
standard to transfer batch jobs between devices
• 3. File transfer, access and management (FTAM),
defines standard for transfer of files between
systems
• 4. Message oriented interchange system (MOTIS),
defines standard for interconnecting different system
in the word
• 5Office document architecture/office document
interchange facility (ODA/ODIF), provides
(to p46)
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Layer 7: Application or user
layer(cont.)
• Layer 7 (cont.)
• 5. (cont.) a standard to allow the transfer, edit and
return of documents across system from multiple
vendors
• 6.Virtual terminal services (VTS), defines the virtual
terminal concept, including characters, graphics,
image, colors etc
(to p33)
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(to p33)
Telecomm Arch. & Standards (cont.)
The following two giants’ machines can also be
linked to the telecomm. standards of ISO/OSI:
1. IBM developed the SNA (Systems Network
Architecture)
2. DEC developed the DNA (Digital Network
Architecture)
(Note: many textbooks review these two architectures and we do not
cover in this subject!)
(Students who wish to gain a copy of these architectures can come to
see me later!)
(to p30)
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Telecomm Arch. & Standards
TCP/IP
(cont.)
• TCP/IP (Transmission Control Protocol/Internet
Protocol),developed by USA Department of
Defense, is also a commonly practiced now
in industry
– it consists of 5 (or 4) layers (namely, physical,
network access, Internet, transport and
application)
(to p50)
(to p30)
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TCP/IP
The OSI
Model
Application
Layer
Application or
Process Layer
Presentation
Layer
Session
Layer
Network
Access
• Provides communications services
for end user applications
• Supports the accomplishment
of telecommunications sessions
Host-to-Host Transport Layer
Transport
Layer
• Supports the organization and
transfer of data between nodes in
the network
Internet Protocol (IP)
Network
Layer
• Provides appropriate routing by
establishing connections among
network links
Network Interface
Data Link
Layer
• Supports error-free organization
and transmission of data in the
network
Physical Layer
Physical
Layer
• Provides physical transmission of
data on the telecommunications
(to p30
media in the network
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Alternative view of 4 layers
(to p59)
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(to p30)
logical and physical connections
• A logical connection is one that exists only
in the software, while a physical connection
is one that exists in the hardware
• Note that in a network architecture, only the
lowest layer contains the physical
connection, while all higher layers contain
logical connections
• Applied in OSI model (to p53)
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Logical and Physical Connections
(continued)
Physical connections in networks
(to p54)
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Network Connections in Action
How does it apply to TCP/IP?
(to p55)
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TCP/IP in action
Note:
(to p56)
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The TCP/IP Protocol Suite in
Action
• Note the flow of data from user to Web
browser and back
• At each layer, information is either added or
removed, depending on whether the data is
leaving or arriving at a workstation
• The adding of information over pre-existing
information is termed encapsulation
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Why?
1) shrinking world by telecomm.
2) direct and indirect use on the job remotely
- direct such as networking
- indirect such as Intranet, telecommute, m-commerce
3) widely use of IT at home such as home
entertainment – itv, icable, www, internet, AI
home appliances
4) new career in telecomm, e-com/business,
telecomm management, and other technical jobs as
reviewed in Figure 1-4
(to p58)
(to p14)
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FIGURE 1-4
A partial list of telecommunications career opportunities.
Conventional
Product Designers
System Analysts
Business Analysts
E-/M- commerce Officers
Network Managers
CIO (Chief Information Officers)
21st Century
(to p57)
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(to p50)
Mobile network
(to p50)
Transaction Comptabilities Application Part (TCAP)
Telephone User Part (TUP
Signaling Connection Control Part (SCCP
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(to p30)
Backbone network
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(to p17)
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(to p23)
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(to p23)
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(to p23)