Why was the OSI developed

• Educational purpose
• To make a standard which help to vender for developed network hardware
• Making a good understanding people of networking concept
• It’s just a model which help making networking concept more depict able 
• Making Layering concept more clear than TCP/IP

Directory Service

User friendly information about network resources

     A directory service or name service, maps the names of network resources to their respective network addresses. With the name service type of directory, a user does not have to remember the physical address of a network resource; providing a name locates the resource. Each resource on the network is considered an object on the directory server. Information about a particular resource is stored as attributes of that object. Information within objects can be made secure so that only users with the available permissions are able to access it. More sophisticated directories are designed with namespaces as Subscribers, Services, Devices, Entitlements, Preferences, Content and so on. This design process is highly related to Identity management.

C Language program to shift array element with previous one

/* Girfa : C Language program to shift array element with previous one*/
/* Find more question Answer on http://girfahelp.blogspot.in/2012/09/some-program-of-c-language.html */
#include<stdio.h>
#include<conio.h>
void main()
{
int ar[5],i,j;
clrscr();
for(i=0;i<5;i++)
ar[i]=i+1;

Subnet Mask - Subnetting

   The subnet mask is used to divide a network into a further sub network within A private network. Subnetting can be used for security purpose in many cases it enable a network administrator to divide a college network for example into many departments like Botany, Art and Science group network.

   Subnetting is applied on host id we reserve host id bits for subnetting from left to right following example depict all aspects of operation 

What is Subnetting?

Subnetting enables the network administrator to further divide the host part of the address into two or more subnets. In this case, a part of the host address is reserved to identify the particular subnet. This is easier to see if we show the IP address in binary format.

The full address is: