Transcript Chapter 4 ppt

An Overview of Telecommunications
and Networks
• Telecommunications: the _________ transmission
of signals for communications (home net)
• Telecommunications medium: anything that
_________ an electronic signal and interfaces
between a sending device and a receiving device
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Transmission Media
• Guided Media
– Twisted pair cable
– Coaxial cable
– _________ optic cable
• Wireless Media
– Microwave transmission
– Cellular transmission
– _________ transmission
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Networks
• Computer network: the _________ media,
devices, and software needed to connect two or
more computer systems or devices
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Advantages of Networks
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streamline work _________ and cut costs
allow people within organizations to collaborate
share hardware, software, and processing power
enable _________ distant work groups to
communicate with each other
allow _________ to share information with external
groups such as suppliers
shorten _________ lead times and response times
support electronic commerce
NBC
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Basic Processing Strategies
• Centralized processing:
• _________ processing:
• Distributed processing:
– Terminal-to-host: “dumb” terminal
– File server:
– Client/server:
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Client/Server Architecture
URL
Database Query
Client
Server
Requests & Parameters
TCP/IP
HTTP
Response & Results
Disks for
Storage
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Network Types
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Personal area network (PAN)
Local area network (LAN)
Metropolitan area network (MAN)
Wide area network (WAN)
International network
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Network Types (continued)
Figure 4.7: A Typical LAN
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Network Types (continued)
Figure 4.8: A Wide Area Network
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Communications Software and
Protocols
• Communications software: software that provides
a number of important functions in a network, such
as error checking and data security
– Network operating system (NOS)
– Network management software
• Communications protocol: a standard set of rules
that controls a telecommunications connection
– Transmission Control Protocol/Internet Protocol
(TCP/IP), IEEE 802.3 (Ethernet), and FireWire.
Bluetooth & 802.11b (Wi-Fi).
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Use and Functioning of the Internet
• Internet: a _________ of interconnected networks,
all freely exchanging information
– ARPANET
• The ancestor of the Internet
• A project started by the U.S. Department of Defense
(DoD) in 1969
– Internet Protocol (IP): _________ standard that
enables traffic to be routed from one network to
another as needed
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How the Internet Works warrior
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Accessing the Internet
Figure 4.10: Several Ways to Access the Internet
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The World Wide Web
Figure 4.11: Sample Hypertext Markup Language
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Intranets
• Intranet
– _________ corporate network built using Internet and
World Wide Web standards and products
– Used by employees to gain access to corporate
information
– Intranets can benefit all kinds of organizations
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Benefits of Intranets
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Reduced costs
improved communication
shared software,
Improved productivity
Increased security
Better customer service Scalability
More cost effective IT spend
Increased competitiveness
Streamlined administration
Easier training of new employees
Calendar and diary sharing working
Extranet-ready 17
Extranets
• Extranet
– A _________ based on Web technologies that links
selected resources of a company’s intranet with its
customers, suppliers, or other business partners
• Virtual private network (VPN): a secure
connection _________ two points across the
Internet
• Tunneling: the process by which VPNs transfer
information by encapsulating traffic in IP packets
over the _________
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Use Extranets for:
• Product Development
• Purchasing and Stocks
• Production
• Orders and Delivery
• Customer Relationships
• Collaborative Working
– Supply chain
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Intranets and Extranets (continued)
Figure 4.12: Virtual Private Network
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Net Issues
• Management issues
• Service and speed issues
• Privacy
– Spyware:
– Cookie:
– Fraud
• Phishing
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Net Issues (continued)
• Security with encryption and firewalls
– Cryptography: _________ a message into a secret
code and changing the encoded message back to
regular text
– Digital signature: encryption technique used to verify
the identity of a message sender for processing
online _________ transactions
– Firewall: a device that sits between an internal
network and the Internet, limiting _________ into and
out of a network based on access policies
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Net Issues (continued)
Figure 4.13: Cryptography is the process of converting a
message into a secret code and changing the encoded
message back into regular text.
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FIREWALLS
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One of the most common defenses for preventing
a security breach is a firewall
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Firewall – hardware and/or software that guards a
private network by analyzing the _________ leaving
and entering the network
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Firewall Capability
Firewall can
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_________ decisions
Enforce _________ policy
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Log internet activity
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Limit
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Focus for
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keeps one section of intranet separate from another
Firewall can not
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_________ insiders
Protect against _________ that do not go through it
Protect against
Protect against new threats
Protect against viruses
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FIREWALLS
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Sample firewall architecture connecting systems
located in Chicago, New York, and Boston
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