Communication and Networking concepts

DIFFERENCE BETWEEN WIRELESS / MOBILE

Video Conferencing -  A two way videophone conversation among multiple participants is called video conferencing. It includes sounds, video, talking and viewing.  We need Internet connection, PC Camera and its Software, videophone Software (Net Meeting) for video conferencing.

WWW – World Wide Web is a protocol that allows to access documents containing text , images , audio and video on the internet.

Web Page – A document on the net is called a web page.

URL – Each web page has a distinct address that is called URL.  Uniform Resource Locator.

The format is

type://address/path

where type represents type of server like ftp or http , address represents address of server and path represents location of file. for example http://encycle.msn.com/getinfo

Hypertext – The webpage contents containing audio, video, text, graphic and even link to some other page.

Hyperlink       -Link to some other page in a web page is called Hyperlink.

Telnet – . It is a program that is used to log on to  remote computer systems.

Web Browser-  It is a program that is used to navigate through the web pages and display their contents.  Ex Internet Explorer,  Netscape Navigator and Mozilla etc

Web Server – A www server that responds to the requests made by web browsers.

Web Site – A location on a web server is called a web site.  It contains web pages and has a unique address.  This address is called URL. like www.microsoft.com

HTML – Hypertext Markup Language – used to develop web pages.

Web Hosting – It is a means of hosting web server application on a computer system through which electronic content on the internet is readily available to any web browser client.

 

 

 

Introduction to Open Source Based software

Open Source Software(OSS): It is the software which can be freely used in terms of making modification , constructing business models around the software and so on .But it does not have to be free of cost. In OSS the source code is freely available to the customer.

Free Software: It means the SW is freely accessible and can be used , changed , improved , copied and distributed by all who wish to do so.No payment is needed to be made for free SW.

Terminologies related to open source:

A software which is free as well as open belongs to  FOSS(Free and Open Source SW).

FLOSS refers to Free Libre and Open Source Software or to Free Livre and Open Source SW.It means a SW which is free as well as open source SW. Libre and Livre means freedom.

GNU:- GNU’s Not Unix. It is a project started to create a system compatible to Unix but not identical with Unix.

FSF: Free Software Foundation: it is non profit organization created for the purpose of supporting free SW movement. It also works on legal and structural issues for Free SW community.

OSI(Open Source Initiative—It specifies the criteria for open source SW and properly defines the terms and specifications of OSS.

W3C: World Wide Web Consortium: It is responsible for producing the SW standards for WWW. It was created in Oct 1994.

Proprietary SW: A software that is neither open nor freely available. This SW’s distribution and modification is either forbidden or requires special permission.. The source code is not available for this SW.

Freeware:- A SW which is available free of cost and allows copying and further distribution but not modification. Its source code is not available.

Shareware: It is made available with the right to redistribute copies, but if anybody intends to use the SW, after a certain period of time, a license fee should be paid.

It is different than FOSS because of

-          the source code is not available

-          Modification is not allowed.

Network Security-

Problems encountered under Network Security:

1. Physical Security Holes-Unauthorized access to computer
2. Software security holes-Badly written programs
3. Inconsistent Usage holes- Assembling a combination of HW and SW such that the system is seriously damaged from security point of view.

Protection Methods:

  Authentication – It is termed as password protection as the authorized user is asked to provide a valid password and if he/she is able to do this, he/she is considered to be an authentic user.

Authorization – It determines whether the service provider has granted access to the web service to the requester. It is performed by asking the user a legal login-id. If the user is able to provide a legal login-id he/she is considered authorized user.

Biometric Systems – It involves some unique aspect of a person’s body such as retina /fingerprints to establish user’s identity.

Encrypted Smart card:- It is a hand held card which generates a token that a computer can recognize. Every time a new and different token is generated, which even cracked or hacked can not be used later.

Firewall – The system designed to prevent unauthorized access to / from a private network is called Firewall.

   Several firewalls are-

• Packet filter
• Application gateway
• Circuit level gateway
• Proxy server

Cookies – It is a message sent by web server to the web browser so that it can keep track of user’s activities on a specific web site.

Crackers – These are the malicious programmers who break into secure systems.

Hackers – The persons who are interested in gaining knowledge about computer system and possibly using this knowledge for playful pranks.

Cyber law – it is a generic term which refers to all the legal and regulatory aspects of internet and World Wide Web.

India’s IT(2000)  Act:- India’s Information Technology Act 2000 notified on 17 Oct,2000. It aims to provide the legal infrastructure for e-commerce in India by governing the transactions through the internet and other electronic medium.

IPR Issues:- It reflects the idea that its subject matter is the product of the mind or the intellect. These could be in the form of Patents, Trademarks ,Copyright etc.

Cyber Crime:- It is an unlawful act where in the computer is either a tool or a target or both.

Types of Cyber crime-

1.      Tampering with computer source documents.

2.      Hacking

3.      Publishing of information which is obscene in electronic form

4.      Child pornography

5.      Accessing protected system

Viruses :-

Viruses: - It is a malicious program which requires a host and is designed to make a system sick just like a real virus.

    Characteristic of a virus

• Able to replicate
• Requires a host program as a carrier
• Activated by external action

    Damages caused by virus

• Destroy parts of program and files
• Decrease the space on hard disk by duplicating files
• Format the hard disk
• Destroy specific executable files
• Cause the system to hang

Trojan horses: It is code hidden in a program such as game or spreadsheet that looks safe to run but has hidden side effects.

Worm: It is a program designed to replicate. These programs run independently and travel from computer to computer across network connection. Most worms disrupt services and create management problems.

Spam  : Refers to electronic junk mail or junk newsgroup postings.

Avoiding Spam:

• Create a filter that finds and does something to e-mail that you suspect as Spam.
• Not to register yourself with true id

Virus protection

• Never use a foreign disk without scanning for virus.
• Always scan files downloaded
• Use licensed SW
• Password protect your PC Make regular backups
• Install and use antivirus SW
• Keeping antivirus SW up-to-date