What is a Domain Name system (DNS) and Address mapping example

 If a person or company has to display its site on the Internet, it is necessary for that company to register a domain name indicating that the site is for commercial (.com) or organizational (.org) purposes, etc.  Is .

Many companies provide the facility of domain names through Internet sites.  Any user has to register or register a domain name for the site to be displayed on the Internet.  The facility of domain name registration is provided by Inter NIC.  The function of NIC is to register the site.  Where that site will be stored, all this is provided by the company that provides the memory to store the site. 

      Nowadays, many companies provide space on their servers to host the users' sites according to the needs of the users.  They charge some price from the consumers for providing this facility.  The following points should be kept in mind while registering a domain name- 

(i) How much fee is to be paid for registration?  

(ii) How much free disk space is available for use?  

(iii) Whether various technical support is available or not?  

(iv) What is the fee to be paid per MB space after the free limit is exhausted?  ,  

(v) How much security is being provided to the information of a consumer so that such information cannot be misused by any unauthorized person? 

Domain names are made up of some words that are separated by periods, such as - 

cs.purdue.edu

Depending on the functionality of the site, the domain names are used according to the following table -

Domain name	Meaning
.com .edu .gov .mil .net .org .APRA .int	For commercial organizations For educational institutions For government agencies For military groups To network  For other organizations  Temporary ARPANET Domain For international organizations

DNS Address Mapping - An efficient, reliable and distributed process is used to map domain names to addresses.  The process of mapping domain names to addresses would have consisted of an independent and corporative system Which is called name server.  A name server is a server that performs the task of translation of a domain name into an IP address. The arrangement of domain name servers in the form of a tree is shown in the figure.

Here the root server holds information about the domain name at the top level.  The structure of the server names in the form of a tree is not so simple, as shown in the figure.  It is getting more and more difficult.