Transcript Introduction to Communications Systems

Introduction to
Communications
Part One: Overview
Kuang Chiu Huang
TCM NCKU
Spring/2008
Information Forerunner
• Keep in touch with telecom related
news, reports and data
• Analyze those information and try to
figure out the trend of telecom
development and rationale of carriers’
investment strategies
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News, Report, and Data
• Source: Information from Taiwan and
foreign countries
• News: Yahoo Technology News,
CommunicationDirect News, BBC
Technology news
• Report: NCC, FCC, NTIA
• Data: Carrier’s website
• Blog: Cybertelecom blog, GigaOm,
TeleFriden
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Goals of This Class
• A clear picture in your mind to know
about communications networks and
basic components. After this course,
you are enabled to identify different
topologies of communication
networks and explain their five
components.
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Outline of the Class
• Warm up
• Chapter 1 Introduction
•Q&A
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Warm Up
• Any question?
• What are differences between
communications & telecommunications
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1-1 DATA COMMUNICATIONS
Telecommunication is the
assisted transmission of signals over a
distance for the purpose of communications
through electronic devices
電信法:指利用有線、無線，以光、電磁系統或其
他科技產品發送、傳 輸或接收符號、信號、文字、
影像、聲音或其他性質之訊息。
簡而言之:指利用電子技術在不同的地點之間傳遞
信息
Topics discussed in this section:
Components
Data Representation
Data Flow
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Figure 1.1 Five components of data communication
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Figure 1.2 Data flow (simplex, half-duplex, and full-duplex)
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1-2 NETWORKS
A network is a set of devices (often referred to as
nodes) connected by communication links. A
node can be a computer, printer, or any other
device capable of sending and/or receiving data
generated by other nodes on the network.
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1-2 Topics of Networks
Distributed processing:
Network Criteria:
Physical Structures:
Network Models:
Categories of Networks:
Interconnection of Networks:
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1-2 Network Criteria
Distributed processing: a task is divided among
multiple computers. Instead of a large machine
Network Criteria:
Performance: how good it is (throughput and
delay)
Reliability:frequency of failure
Security: protecting data from unauthorized
access, damage and change
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1-2 Network Physical Structure & Categories
Physical Structures:
P2P
P2MP
Network Models: ISO’s OSI
Categories of Networks:
LAN: local area network
WAN: wide area network
MAN: metropolitan area network
Interconnection of Networks: Internetwork
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Figure 1.3 Types of connections: point-to-point and multipoint
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Figure 1.4 Categories of topology
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Figure 1.5 A fully connected mesh topology (five devices)
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Figure 1.6 A star topology connecting four stations
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Figure 1.7 A bus topology connecting three stations
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Figure 1.8 A ring topology connecting six stations
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Figure 1.9 A hybrid topology: a star backbone with three bus networks
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Figure 1.10 An isolated LAN connecting 12 computers to a hub in a closet
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Figure 1.11 WANs: a switched WAN and a point-to-point WAN
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Figure 1.12 A heterogeneous network made of four WANs and two LANs
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1-3 THE INTERNET
The Internet has revolutionized many aspects of our daily
lives. It has affected the way we do business as well as the
way we spend our leisure time. The Internet is a
communication system that has brought a wealth of
information to our fingertips and organized it for our use.
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1-3 THE INTERNET BACKGROUND
Why: Connect computers together to exploit
valuable resources
Where: from the US
Who: DoD ARPA (ARPANET)
When: mid-1960s
What: IMP (interface message process) as
communication device to connect four nodes
together
How: NCP (network control protocol) to
Internetting Project to TCP/IP
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Figure 1.13 Hierarchical organization of the Internet
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1-4 PROTOCOLS AND STANDARDS
In this section, we define two widely used terms: protocols
and standards. First, we define protocol, which is
synonymous with rule. Then we discuss standards, which
are agreed-upon rules.
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Homework 2
Type your answers in A4 size papers with your
name
•Page 24: #4, #8, #9, #12, #13, #16 #17
•Page 25: #21, #24
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Thank you!
Q&A
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