Transcript Software Engineering Syllabus

Chapter 4
Networking and the Internet
Introduction to CS
1st Semester, 2012 Sanghyun Park
Outline
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Network Fundamentals
Internet
World Wide Web
Internet Protocols
Security (will be covered in 12th week)
Network Classification (1/3)
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Two broad categories
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Ownership
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____ (Local Area Network):
normally consists of a collection of computers in a single building or
building complex, e.g., university campus
____ (Wide Area Network): links machines that may be in neighboring
cities or an opposite side of the world
Public domain  _____ network (Internet)
Private entity  ______ network or _________ network
Network ________ (pattern in which machines are connected)
 Ring, bus, star, irregular
Network Classification (2/3)
The machines are connected
in a ________ fashion
The machines are all connected
to a common communication line
called a _____
Network Classification (3/3)
One machine serves as a ____ to which
all the others are connected
The machines are connected in what
appears to be a _________ manner
Bridge and Router (1/2)
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At times it becomes necessary to ________ two existing networks
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When the networks are compatible, this can be done by merely
connecting the networks by a coupling device called a _______
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When two networks are connected via a bridge, the result is simply
a larger _______ network
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It is often necessary to join two networks whose characteristics are
not compatible
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In this case, the two networks must be connected in a manner that
builds a network of networks, which is known as an _______
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The connection between two networks to form an internet is
handled by a machine known as a ______
Bridge and Router (2/2)
Inter-Process Communication
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Client-server
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One server, many clients
Server must execute _____________
_______ initiates communication
Peer-to-peer
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Two processes communicating as _______
Peer processes can be ___________
Client/Server Model
C/S Model Compared To
Peer-To-Peer Model
Distributed Systems
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Systems with parts that run on _________ computers
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Infrastructure usually provided by standardized toolkits
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Examples include:
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Enterprise JavaBeans from ________________
.NET framework from ___________
The Internet
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A network of networks  ________
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An example of an internet is the _________
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Originated from a research program initiated in 1973 by the
Defense Advanced Research Projects Agency (DARPA)
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Internet is a combination of WANs and LANs involving maybe
millions of machines
Internet Topology (1/2)
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The Internet can be viewed as a collection of _______, each of which
is relatively small internet operated by a _______ organization
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To establish a domain, the entity desiring the domain must register
with ______ (Internet Corporation for Assigned Names and Numbers)
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A domain is attached to the existing Internet via a _______ that
connects a network in the domain to a network already in the Internet
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This particular router is called the domain’s _________
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The gateways of a number of domains can be connected to form a
regional network of gateways
Internet Topology (2/2)
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A typical approach to connecting to the Internet
Internet Addressing (1/2)
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Each machine in the Internet is assigned a unique address,
called an ___________
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Each IP address is a pattern of _______ consisting of two parts:
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Identify the domain (______________)
Identify the particular machine within the domain (_____________)
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Network identifier is assigned by ICANN at time of domain
establishment and registration (guarantees __________ of network
identifier)
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The host address is assigned by the domain’s local authority
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Example
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192.207.177 (network identifier of Addison-Wesley publishing co.)
192.207.177.133 (a machine within this company)
Internet Addressing (2/2)
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ICANN assigns each domain a unique __________ address
known as domain name (edu, gov, org, com, … first-level domains)
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Break domain into sub-domains
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We need a ________ between numeric addresses and mnemonic
addresses (each local authority maintains such _________)
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Directory is implemented within the domain in the form of a server
called a ____________ (DNS  Domain Name System)
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Name server provides ________ for mnemonic addresses to obtain
the corresponding numeric addresses
World Wide Web (1/3)
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_________ is a text containing words, phrases, or images that are
linked to other documents
When hypertext contains sounds and video, it is called __________
Reader of hypertext documents can explore related documents
A _____ of related information is formed
Web that has evolved on the Internet spans the entire globe and is
known as ________________
Request
Client machine
Browser
Server machine
Serves web pages
Reply
World Wide Web (2/3)
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Each document is identified by a _________ address
This unique address is called a _____ (Uniform Resource Locator)
The URL allows to identify the ______, the ________ in use, and a
desired _________
Sometimes a URL does not explicitly identify a document, in such
case a predetermined document is often returned
(usually a ______ page)
World Wide Web (3/3)
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A hypertext document contains several ________ that describe
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How the document should _______ within the browser
Which items within the document are to be ______ to other documents
Systems of markers known as Hypertext Markup Language (____)
Finding information on the WWW  ________ Engines
Layered Approach to Internet Software
(1/2)
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A principal task of network software is to provide the ___________
required for ___________ message from one machine to another
Package-shipping example
The transportation of the gift would be carried out by a three-level hierarchy:
(1) the _____ level, (2) the ________ company, and (3) the ________
Layered Approach to Internet Software
(2/2)
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The Internet software has _____ layers rather than three:
TCP/IP Protocol Suite (1/2)
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The _______ protocol suite is a collection of protocols used by the
Internet to implement the four-level hierarchy just described
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Actually, TCP (Transmission Control Protocol) and IP (Internet
Protocol) are the names of only two of the protocols in this collection
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TCP/IP protocol suite provides two ways of implementing the
_______ layer: TCP and UDP (User Datagram Protocol)
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The _________ layer may choose to send data via a TCP or UDP
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IP is the Internet’s standard for the _________ layer
TCP/IP Protocol Suite (2/2)