Networking Continued

Dr. Mahdi Nasereddin

Analog Vs Digital

Analog: A continuous electrical waveMake frequencyUsed in the telephone wire

Digital: Individual electrical pulses that represent the

bits grouped together into byteUsed Binary number (0,1) in computer

aa

Terminal

Modem

Modem

Analogsignals

Phone line

Digitalsignals

Digitalsignals

Computer

-The word modem comes from the terms modulation and demodulation-A device that switches electronic signal from digital to analog or from analog to digital

How a Modem Works

ModulationDemodulation

WAN(Wide Area Network)

LAN(Local Area Network)

Networks Near and Far

There are two general types of computer networks:

LAN (Local Area Network)

A LAN is a network in which the computers are physically close to each other

They typically share peripherals (printers and servers)

Each computer and shared peripheral isa node on the LAN

A LAN might contain PCs with different OSs

A WAN is a network in which the computers are a great distance from one another

Connections are made via telephone lines, satellites, and/or microwave relay towers

Each network site is a nodeExample: The internet

WAN (Wide Area Network)

WAN (Wide Area Network)

WANs are often made up of LANs

Internet

AKA the Net A worldwide collection of Network Link millions of business, government agencies,

educational institutions, and individuals

Business InternetIntranet Vs. Extranet

Intranet an internal network that uses

Internet technologies A private network Make company information

accessible to employee and facilities

Extranet A similar to Intranet To facilitate communication

and trade between an organization and business partners

allows customers or supplies to access part of intranet

World Wide Web Consotium(W3C)

In 1994, found an organization by Tim Berners-Lee Make the Web University accessible Included (Extensible) Hypertext Markup Language

(XHTML), Cascading Style Sheet (CSS), Extensible Markup Language(XML)10

Provides extensive resources on Internet and Web technology

http://www.w3.org The website has several good validation tools