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Showing posts from September 30, 2010

Subnet masking

Subnetting an IP Network is done primarily for better utilization of available IP address space, and routing purpose. Other reasons include better organization, use of different physical media (such as Ethernet, WAN, etc.),  and securing network resources. A subnet mask enables you to identify the network and node parts of the address. The network bits are represented by the 1s in the mask, and the node bits are represented by the 0s. A logical AND operation between the IP address and the subnet mask provides the Network Address. For example, using our test IP address and the default Class C subnet mask, we get: 192.189.210.078: 1100 0000.1011 1101.1101 0010.0100 1110 Class C IP Address 255.255.255.000: 1111 1111.1111 1111.1111 1111.0000 0000 Default Class C subnet mask  192.189.210.0         1100 0000 1011 1101 1101 0010 0000 0000 As can be seen above, by using and AND operator, we can compute the network portion of an IP address.  The network portion for the

IP Addressing

An IP address is a unique logical identifier for a node or host connection on an IP network. An IP address is a 32 bit binary number, and represented as 4 decimal values of 8 bits each. The decimal values range from 0 to 255. This is known as "dotted decimal" notation. Example: 192.189.210.078 It is sometimes useful to view the values in their binary form. 192     .189     .210     .078 11000000.10111101.11010010.1001110 Every IP address consists of network identifier and node identifier. The IP network is divided based on Class of network. The class of network is determined by the leading bits of the IP address as shown below. Address Classes There are 5 different address classes. You can determine which class any IP address is in by examining the first 4 bits of the IP address. Class A addresses begin with 0xxx , or 1 to 126 decimal. Class B addresses begin with 10xx , or 128 to 191 decim