Transcript 21_Networkingx

Advanced Programming in Java
Networking
Mehdi Einali
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agenda
Basic Concepts on Networking
IP Address
Protocol
Ports
The Client/Server Paradigm
Sockets
The Java Networking Package
The ServerSocket and the Socket Class
The MulticastSocket and the DatagramPacket
Class
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Networking
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Basic Concepts on Networking
The Internet
A global network of computers connected
together in various ways
Remains functional despite of diversity of
hardware and software connected together
Possible through communication standards
defined and conformed to
Guarantee compatibility and reliability of
communication
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IP Address
Logically similar to the traditional mailing address
An address uniquely identifies a particular object
Each computer connected to the Internet has a
unique IP address
(Version 4) A 32-bit number used to uniquely
identify each computer connected to the Internet
192.1.1.1
docs.rinet.ru(via dns)
4294967296 (232) addresses
Pv6 uses a 128-bit address, theoretically
allowing 2128, or
approximately 3.4×1038 addresses
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Protocol
Why protocols?
Different types of communication occurring
over the Internet
Each type of communication requires a specific
and unique protocol
Definition
Set of rules and standards that define a certain
type of Internet communication
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Protocol-2
Consider this type of conversation:
"Hello."
"Hello. Good afternoon. May I please speak at
Joan?"
"Okay, please wait for a while."
"Thanks.“
Social protocol used in a telephone
conversation
Gives us confidence and familiarity of
knowing what to do
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Protocol stack
Post Cargo
Post Cargo
Tehran
Envelope Package
Envelope Package
INOC
Envelope
Envelope
Loan Request
Loan Request
Formal Letter
Formal Letter
Persian Language
Persian Language
Persian Alphabet
Persian Alphabet
Paper and Pen
Paper and Pen
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Accounting
Loan Manager
Network protocol stack
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Net protocols
Some important protocols used over the
Internet
Hypertext Transfer Protocol (HTTP)
Used to transfer HTML documents on the Web
File Transfer Protocol (FTP)
More general compared to HTTP
Allows you to transfer binary files over the
Internet
Both protocols have their own set of rules
and standards on how data is transferred
Java provides support for both protocols
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Ports
Protocols only make sense when used in the
context of a service
HTTP protocol is used when you are providing Web
content through an HTTP service
Each computer on the Internet can provide a variety of
services
Why Ports?
Ports locate appropriate process with is responsible to
service
A 16-bit number that identifies each service
offered by a network server
80 : http, 21: ftp
Given port values below 1024
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Ports
192.168.1.2
90.98.210.156
192.168.1.123
192.168.1.1
192.168.1.3
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Transport layer protocols
TCP
UDP
Acronym for
Transmission Control
Protocol
User Datagram Protocol or
Universal Datagram Protocol
Connection
TCP is a connectionoriented protocol.
UDP is a connectionless protocol
TCP is suited for
applications that require
high reliability, and
transmission time is
relatively less critical.
UDP is suitable for applications
that need fast, efficient
transmission, such as games.
UDP's stateless nature is also
useful for servers that answer
small queries from huge numbers
of clients
Use by other
protocols
HTTP, HTTPs, FTP, SMTP,
Telnet
DNS, DHCP, TFTP, SNMP, RIP,
VOIP.Ping
Java Classes
ServerSocket, Socket
DatagramSocket,DatagramPacket
Usage
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Java network api
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url vs socket
Socket programing
Working with sockets to do network operation.
It work on transportation layer(building its own
application based on it)
URL processing
Work with URL objects
Based on HTTP protocol( don’t need to work
with underlying transport layer e.g. sockets)
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socket
Definitions:
Software abstraction for an input or output
medium of communication
Communication channels that enable you to
transfer data through a particular port
An endpoint for communication between two
machines
A particular type of network communication
used in most Java network programming
Java performs all of its low-level network
communication through sockets
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The ServerSocket Class
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The Socket Class
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end
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