1. Networking Fundamentals

4. IPv4 Addressing

4.1 Subnetting :

Subnetting is nothing but creating networks within a network. Subnetting allows an organization with a single IP address (Class A /ClassB /ClassC) to have multiple subnetworks, thus allowing several physical networks with in the organization.

Addresses are written using decimal numbers separated by decimal points. This is called dotted decimal notation of expressing IP addresses.

The different classes of IP addresses is as below:

Class Format Leading Bit Pattern Network address Range Maximum networks Maximum host/nodes A N.H.H.H 0 0 - 126 127 16,777,214 B N.N.H.H 10 128 - 191 16,384 65,534 C N.N.N.H 110 192 - 223 20,971,52 254 D Not defined 1110 224 -255 Not defined Not defined E Not defined 1111 240-255 Not defined Not defined

Network address of all zeros means "This network or segment.

Network address of all 1s means "all networks", same as hexadecimal of all Fs.

Network number 127 is reserved for loopback tests.

Host (Node) address of all zeros mean "This Host (Node)".

Host (Node) address of all 1s mean "all Hosts (Nodes) " on the specified network.

1. The address range and the corresponding binary values for the first octet of IP classes are as given below: