Transcript 204325 Data Communication and Computer Networks

Second Semester, 2014
Data Communications and
Network Programming:
Course Introduction
Asst. Prof. Chaiporn Jaikaeo, Ph.D.
[email protected]
http://www.cpe.ku.ac.th/~cpj
Computer Engineering Department
Kasetsart University, Bangkok, Thailand
Most materials in this presentation were prepared by Assoc. Prof. Anan Phoenphoem (http://www.cpe.ku.ac.th/~anan)
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Outline
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Motivation
Growth of Computer Networking
Data Communication
Networks
Protocols and Standards
Standard Organizations
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Motivations
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Efficient way to share resources
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Cost – less expensive
Accessibility – easier
Efficient way to exchange information
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Time – faster
Size – bigger
Correctness – accurate
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Example - A Computer Network
Laptop
iM ac
Workstation
Media Links
Server
SD
Printer
Scanner
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Data Communication
Hi,
Hi,
how
how
are
are
you?
you?
Hi, how are you?
Hi, how are you?
Computer
01010001
User
01010001
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Data Comm. Components
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Message
Hi
How are you
doing?
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Protocol
Sender
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Receiver
Medium
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Protocols and Standards
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Protocol
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A set of rules governing data communications
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Syntax: format of data block
Semantics: meaning of each section
Timing: speed and sequencing
Standards
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De facto (in practice) standards
 not approved but widely adopted
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De jure (in law) standards
 approved by a standard organization, e.g., ISO, IEEE
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Protocols and Standards
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To communicate, two devices must follow
the same set of communication protocols
E.g., they must
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be connected to the same medium
understand each other's messages
In other words, they comply with the same
standard
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Data Representation Standards
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Numbers
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ASCII, Unicode
Images
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Text
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8/16/32 bit integers
floating point
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Bit patterns, Graphics formats JPG/GIF/etc
Audio  Samples of continuous signal
Video  Sequence of bitmap images
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Connection Standards
Company B
Company A
Network Interface Card (NIC)
Company C
Company D
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Internetworking
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How to allow devices from different standards
to communicate
Gateways/routers – devices capable of
communicating in several standards
These become "network of networks"
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The Internet
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The largest internetwork (network of networks) in
the world
Devices communicating with TCP/IP protocol suite at
high level
Stanford
U. of Utah
UC Santa Barbara
UCLA
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Internet Growth
#computers attached to Internet
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Recent and Future Trends
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The availability of high-quality
teleconferencing systems
Some social networking applications such as
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Facebook
Twitter
Google+
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Many others
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The Internet of Things (IoT)
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Future of the Internet
http://www.computerworld.com/s/article/print/9191518/Final_IPv4_addresses_to_be_issued_within_months_NRO_warns
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Future of the Internet
http://www.computerworld.com/s/article/9207961/Update_ICANN_assigns_its_last_IPv4_addresses
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Future of the Internet
http://www.zdnet.com/blog/networking/its-official-asias-just-run-out-of-ipv4-addresses/948
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Internet of Things
http://www.opinno.com/en/content/internet-things-0
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Connected Living
https://devcentral.f5.com/articles/security-sidebar-defending-the-internet-of-things
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Connected Living
http://www.jumpthecurve.net/wp-content/uploads/2014/03/ericssonthings1.jpg
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Future of the Internet
http://www.itworld.com/networking/231929/usenix-google-deploys-ipv6-internal-network
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What Will We Learn in this course
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Data communication concepts
Computer networking devices
Internet protocol suite (TCP/IP)
Capture and analyze network traffic of wellknown applications
Network programming
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Standalone socket applications
Web-based applications
Web services
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Languages and Tools
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Basic network tools
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Network traffic monitor
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ping, traceroute (tracert on Windows)
Wireshark
Programming
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Java (with Groovy shell)
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Ping
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Trace Route
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Monitoring Network Traffic
Sample results from Wireshark
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Application Program Interface (API)
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Set of operation for application programmer
Specify arguments and semantics
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Berkeley Socket API
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API for developing applications that perform inter-process
communication in C/C++
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Example functions
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most commonly for communications across a computer network,
especially UNIX
listen – used by server to wait for contact from client
connect – used by client to contact server
send – used by either client or server to send data
recv – used by either client or server to receive data
Java, .NET, Python, etc. provide convenient wrappers around
socket API
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Easier to write than C/C++
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Web APIs (Web Services)
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APIs defining set of request and response
messages via web context (i.e., HTTP)
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usually in Extensible Markup Language (XML)
or JavaScript Object Notation (JSON) format
Examples
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Facebook API
Twitter API
Various Google APIs
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Summary
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Motivations of computer networking
Data Communication components
Network application programming and APIs
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