Internet Technology

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INSY402

S.A.Idowu

email:saidowuclass@yahoo.co.in

1

Lesson1,2 and 3
 Internet



Network Edge
Network Core

 Core Network Switching Schemes



Circuit Switching
Packet Switching (pipelining)

 Network Delay





Nodal Processing Delay
Queuing Delay
Transmission Delay
Propagation Delay

2

OSI 7-Layer Model
In the 70's, computer networks were ad hoc, vendor-specific
Open Systems Interconnection model







developed by the ISO (International Organization
for Standardization) in 1984
provides an abstract model of networking
divides the tasks involved in moving information
between networked computers into 7 task groups
each task group is assigned a layer

Each layer is reasonably self-contained, so




can be implemented independently
changes/updates to a layer need not effect other
layers
3

Protocol Layers










Application layer


describes how applications will communicate
e.g., HTTP, FTP, Telnet, SMTP

Presentation layer


describes the form of data being transferred & ensures that it will be readable by receiver
e.g., floating point formats, data compression, encryption

Session layer


describes the organization of large data sequences & manages communication session
e.g., coordinates requests/responses (“traffic flow”)

Transport layer


describes the quality and nature of data delivery
e.g., how retransmissions are used to ensure delivery

Network layer


describes how a series of exchanges over various data links can deliver data across a network
e.g., addressing and routing

Data Link layer


describes the logical organization of data bits transmitted on a particular medium
e.g., frame sequencing, error notification

Physical layer:


describes the physical & electrical properties of the communications media
e.g., voltage levels, data rates, max distances
4

Protocols
– Protocol
• Architecture  Service
• Rules of communication
FTP

HTTP

RTP

TFTP
UDP

TCP
IP
Ethernet

CAT-5

802.11

Single-Mode
Fiber



PPP

RS-232

5

Application layer





Principles of network applications
Web and HTTP
FTP
Electronic Mail
– SMTP, POP3, IMAP

• DNS
• P2P file sharing

6

Goals:
 conceptual,

implementation
aspects of network
application protocols




transport-layer
service models
client-server
paradigm
peer-to-peer
paradigm

 learn about protocols

by examining popular
application-level
protocols






HTTP
FTP
SMTP / POP3 / IMAP
DNS

7

Web based Applications
Programming/Internet Programming




Web service is a kind of client / server process
Need interaction between client and server
Programming for providing Web service can
also be divided into


Client-side programming: to define the operation to be performed on the client’s machine(can download program with Web page, execute on client machine)



Server-side programming: to define the operation to be performed on the server( in other words can store and execute program on the web server)
8

Internet
Database

Web Server

Web Client

Server-side Programming

Client-side Programming

Skills that are often required:
• CGI
• PHP
• ASP
• Perl
• Java Servlet, …

Skills that are often required:
• XHTML
• Javascript
• Java
• Dreamweaver
• Flash
• SMIL, XML …

9

Some network apps(web-applications)
 E-mail

 Internet telephone

 Web

 Real-time video

 Instant messaging

 Remote login
 P2P file sharing

conference
 Massive parallel
computing

 Multi-user network

games
 Streaming stored
video clips

10

Web –based applications development


Three steps for web-based applications
implementation.
1. Obtain the appropriate equipment
 Web Server – hardware and software
2. Register the Web Server to an Internet
Service Provider...
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