This tutorial explains the network address, broadcast address and IP address with examples. Find out what the network address is, the types of network address, how to find out in detail the default network address and broadcast address of any IP class, as well as the network address such as unicast , multicasting and broadcasting.

IP adress

An IP address is the unique identity of an interface in an IP network. IP addresses are like postal addresses. In order to send and receive packages via the postal system, each house needs a unique postal address. Like it, to send and receive IP packets over an IP network, each interface needs a unique IP address.

IP address format

An IP address consists of 32 bits. These bits are divided into four equal sections. The sections are separated by periods and written in a sequence.

In the measurement, 8 bits are equal to a byte or byte. We can therefore also say that an IP address consists of four bytes or bytes separated by periods.

Two popular notations are used to write an IP address, binary and decimal.

In binary notation, the four bytes are written in binary format. For example, some IP addresses in binary format are listed below.

00001010.00001010.00001010.00001010
10101100.10101000.00000001.00000001
11000000.10101000.00000001.00000001

In decimal notation, the four bytes are written in decimal format. An equivalent decimal value of the byte is used in each section. For example, the IP addresses in the above example are listed below in decimal format.

10.10.10.10
172.168.1.1
192.168.1.1

In real life, you rarely need to write an IP address in binary format. But if you are preparing for a Cisco exam, I highly recommend that you learn the binary format with the decimal format. Almost all Cisco exams have questions about IP addresses. Learning binary and decimal notations will help you resolve questions related to IP addressing more effectively.

IP address components

As we saw earlier, an IP address is like a postal address. Whether it is a postal address or an IP address, it contains two addresses, a group address and an individual address. In a particular group, the group address is common to all members and the individual address is unique for each member.

In the postal system, the group address and the individual addresses are called the zone address and the home address. In IP network, these addresses are called respectively network address and host address.

The following figure shows some examples of postal system and IP network addresses.

IP address and subnet mask

Subnet mask

In an IP address, the number of bits used in the network address and the number of bits remaining for the host address are determined by a subnet mask. Like an IP address, the subnet mask is also a 32-bit long address and can be written in binary and decimal notation.

Here are examples of subnet masks in binary notation: –

11111111.00000000.00000000.00000000
11111111.11111111.00000000.00000000
11111111.11111111.11111111.00000000

Examples of the subnet mask in decimal notation are: –

255.0.0.0
255.255.0.0
255.255.255.0

The IP address and the subnet mask are always used together. Without an IP address, the subnet mask is just a number and vice versa. Below are some examples of writing a correct IP address.

Examples of IP addresses with subnet mask in binary format

00001010.00001010.00001010.00001010
11111111.00000000.00000000.00000000

10101100.10101000.00000001.00000001
11111111.11111111.00000000.00000000

11000000.10101000.00000001.00000001
11111111.11111111.11111111.00000000

Examples of IP addresses with subnet mask in decimal format

10.10.10.10
255.0.0.0

172.168.1.1
255.255.0.0

192.168.1.1
255.255.255.0

IP classes

There are 4,294,967,296 IP addresses. Based on the following rules, IP addresses are classified into five classes; A, B, C, D and E.

  • In class A, the first bit of the first byte is always deactivated (0).
  • In class B, the first bit of the first byte always remains on and the second bit of the first byte always remains off.
  • In class C, the first two bits of the first byte always remain activated and the third bit of the first byte always remains deactivated.
  • In class D, the first three bits of the first byte always remain activated and the fourth bit of the first byte always remains deactivated.
  • In class E, the first four bits of the first byte always stay on.

By activating and deactivating all the remaining bits of the first byte, we can create the first and the last address of this class.

Class Binary start bit (s) Decimal value of the first byte in the range
A 0 0 to 127
B ten 128 to 191
VS 110 192 to 223
re 1110 224 to 239
E 1111 240 to 255

The class of an IP address is determined by the value of the first byte or byte.

  • If the value in the first byte is in the range 0 to 127, it’s a class A address.
  • If the value in the first byte is in the range 128 to 191, it’s a class B address.
  • If the value in the first byte is in the range 192 to 223, it’s a class VS address.
  • If the value in the first byte is in the range 224 to 239, it’s a class re address.
  • If the value in the first byte is in the range 240 to 255, it’s a class E address.
Class Departure address End address Subnet mask
A 0.0.0.0 127255255255 255.0.0.0
B 128.0.0.0 191255255255 255.255.0.0
VS 192.0.0.0 223.255.255.255 255.255.255.0
re 224.0.0.0 239.255.255.255 Not applicable
E 240.0.0.0 255.255.255.255 Not applicable

Although we have almost 4.3 billion IP addresses, not all of them are available for terminals. From these addresses, the following addresses are reserved and cannot be assigned to the terminals.

  • 0.0.0.0: – This address represents all networks.
  • 127.0.0.0 to 127.255.255.255: – This IP range is reserved for loopback tests.
  • 224.0.0.0 to 239.255.255.255 (Class D): – This IP class is reserved for multicasting.
  • 240.0.0.0 to 255.255.255.254 (Class E): – This IP class is reserved for future use.
  • 255.255.255.255: – This address represents all hosts.

Besides these reserved addresses, we cannot use the first and the last IP address of each network either. The first IP address is reserved for the network address and the last IP address is reserved for the broadcast address. We can only use the addresses available between the network address and the broadcast address for terminals.

IP address vs network address

As noted, an IP address is the combination of two separate addresses, the network address and the host address. If we exclude the host address from the IP address, we will get the network address. Simply put, a network address is an IP address without a host address. In technical terms, a network address is an IP address in which all host bits are disabled.

We can only enable or disable host bits. We cannot activate or deactivate reserved network bits. In class A, B and C, the first 8, 16 and 24 bits are reserved for network addresses, respectively.

network bits and host bits

IP address vs host address

Any IP operation such as the creation of a network address or a host address and the creation of subnets are always performed in the host part of an IP address. We can turn host bits on and off as needed. In classes A, B and C, the last 24 bits, 16 bits and 8 bits are defined as host bits respectively.

Private IP addresses vs public IP addresses

In classes A, B and C, the following IP addresses are defined as private IP addresses: –

  • In class A: – 10.0.0.0 to 10.255.255.255
  • In class B: – 172.16.0.0 to 172.31.255.255
  • In class C: – 192.168.0.0 to 192.168.255.255

With the exception of private IP addresses and reserved IP addresses, all remaining Class A, B and C IP addresses are considered public IP addresses.

Public IP addresses are used in public networks such as the Internet. Public IP addresses are managed and regulated by ICANN (Internet Corporation for Assigned Names and Numbers).

Private IP addresses are used in a private network. Private IP addresses are locally significant and cannot be routed over the public network.

Network addressing

There are three types of network addresses; unicast, multicast and broadcast.

Unicast address

The unicast address represents an individual terminal device. If an IP packet is sent to a unicast address, it is intended only for that particular recipient. Unicast addresses are generally used by end devices for end-to-end communication.

unicast

Multicast address

The multicast address represents a group of devices. If an IP packet is sent to a multicast address, it is intended for all members of this group. Multicast addresses are generally used by network devices to run their own services.

multicast

Mailing address

The broadcast address represents all devices on the network. If an IP packet is sent to a broadcast address, it is intended for all devices on this network. Broadcast addresses are generally used to locate hosts or services in the network.

spread

The differences between the multicast address and the broadcast address are as follows: –

  • The multicast address represents only one group of devices on a particular network while the broadcast address represents all the devices on that particular network.
  • Depending on the configuration, messages sent to a multicast address are normally allowed to go through the router. Messages sent to a broadcast address are never allowed to pass through the router.

That’s it for this part. In the next section, we will learn what the IP subnet is and why it is done in computer networks. If you have any suggestions, comments, or comments on this tutorial, let me know. If you like this tutorial, don’t forget to share it via your favorite social platform.

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