IP address and Subnet Mask

IP address

For constructing a network, first, we need to understand how IP address works. An IP address is an Internet protocol. It is primarily responsible for routing packets across a packet switched network. The IP address is made up of 32 binary bits that are divisible to a network portion and host portion. The 32 binary bits are broken into four octets (1 octet = 8 bits). Each octet is converted to decimal and separated by a period (dot).

An IP address consists of two segments.

Network ID- The network ID identifies the network where the computer resides

Host ID- The portion that identifies the computer on that network

Introductionto CCNA

These 32 bits are broken into four octets (1 octet = 8 bits). The value in each octet ranges from 0 to 255 decimal. The right most bit of octet holds a value of 20 and gradually increases till 27 as shown below.

Let's take another example,

For example, we have an IP address 10.10.16.1, then first the address will be broken down into the following octet.

.10

.10

.16

.1

The value in each octet ranges from 0 to 255 decimal. Now, if you convert them into a binary form. It will look something like this, 00001010.00001010.00010000.00000001.

IP addressclasses

IP addresses are classified into different classes:

ClassCategories

Class A

0-127

For internet communication

Class B

128-191

For internet communication

Class C

192-223

For internet communication

Class D

224-239

Reserved for Multicasting

Class E

240-254

Reserved for research and experiments

To communicate over the internet, private ranges of IP addresses are as per below.

Class Categories

Class A

10.0.0.0 – 10.255.255.255

Class B

172.16.0.0 - 172.31.255.255

Class C

192-223 - 192.168.255.255

Subnet and Subnet Mask

For any organization, you might require a small network of several dozen standalone machines. For that, one must require setting up a network with more than 1000 hosts in several buildings. This arrangement can be made by dividing the network into subdivision known as Subnets.

The size of network will affect,

• ·         Network class you apply for
• ·         Network number you receive
• ·         IP addressing scheme you use for your network

Performance can be adversely affected under heavy traffic loads, due to collisions and the resulting retransmissions. For that subnet masking can be a useful strategy. Applying the subnet mask to an IP address, split IP address into two parts extended network address and host address.

Subnet mask helps you to pinpoint where the end points on the subnet are if you are provided within that subnet.

Different class has default subnet masks,

Class A- 255.0.0.0

Class B- 255.255.0.0

Class C- 255.255.255.0