Structure of the Internet

Internet Structure LAN

LANISP

InternetBackbone

Addresses Your PC

Web Sitewww.visitme.com

192.168.2.215

26.14.37.198

Domain Name System

Domain Name Server

Message Flow

Internet Foundation Your PC

Web Site

Transmission Control Protocol/Internet Protocol (TCP/IP)

Client/Server Applications

Client/Server Application

Server

Client

ApplicationProtocol

Request

Response

Division of Labor in a Client/Server System

Server

Client

Interface

Processing

DataManagement

Display Form

Validate Data Compute TotalCompute Tax

Check InventoryUpdate Inventory

Multi-tiered Client/Server Application

Application Server

Client

DataManagement

DatabaseServer

InterfaceProcessing

ProcessingData

Management

Internet Applications

Internet Applications (i.e., Web Application)

Server

Client

ApplicationProtocol

Web ServerWeb

BrowserHTTP

(Hypertext Transfer Protocol)

Common Internet Application Protocols

Server

Client

ApplicationProtocol

HTTP – Web

SMTP – E-mail

FTP – File Transfer

IRC – Chat

Companies can, and do, create their own application protocols.

192.168.2.215

26.14.37.198

Ports

Server

Client

Web ServerWeb

Browser

HTTP

SMTP

E-mailServer

E-mailClient

251837

802134

Web Technologies

Web Browsers and Servers

Web ServersWeb

Browsers

Internet Explorer

Netscape

Mozilla

Opera

Microsoft IIS

Netscape Internet Server

Apache

Web Development Options

Web Server

WebBrowser

HTML

Scripts

Executables

Executables

Scripts

SQL

Web Programming Tools

Web Server

WebBrowser

Java/JavaScript/JScript

Visual Basic/VBScript

PERL

ASP/JSP

C/C++/COBOL/…