COA Tutorial

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Local Broadcast Address and loopback address

In computer networking, if you send the data from one source to another source or group of sources in the form of packets, then this is called casting.

We can categorize the casting upon the number of receiver sources which are following:

  1. Unicast
  2. Broadcast
  3. Multicast

1. Unicast

When in a network, one host sends the data to another host in the same or different network then this is referred to as Unicast. In Unicast, the number of sources and destinations is always one.

The source host needs the IP address of the destination host, and then it can easily send the data in the form of packets.

For example, when we request some data from a hyperlink, the requested data is only received by the server on our local computer. So there is a direct transmission of data from one source to another source.

This is also referred to as one-to-one communication.

2. Broadcast

When one host sends the data to all the other hosts present in the same network or another network then this is called broadcasting.

One of the popular examples is radio channels. Radio channels broadcast their songs to a particular channel, and all the people on that channel can easily listen to those songs.

Another example of broadcast is the TV channels when these channels broadcast their shows with the help of satellites, then every device that can access these channels can see their shows.

It is also called one-to-many communication.

When receiver hosts are in the same network as the transmitter network, then this is called local broadcasting.

For local broadcasting, the sender needs the IP address of all the receiver hosts. So in IPV4, the address is reserved for all the local broadcasts, and it is called the local broadcast address.

Local broadcast address is, and in the binary form, it is


For example, let's consider a network where 4 sources ( source1, source2, source3, and source4) are present.

If we want to consider the local broadcast in this network, then we will send the data to all the sources from one node.

Let's suppose the IP address of source 1 is

The IP address of source 2 is

The IP address of source 3 is

The IP address of source 4 is

Now, as source we will consider source 1 and in destination we will put the IP address as As we broadcast the message then all the nodes and the router connected to this network will receive the message in the form of packets.

If the sender wants to send the data to all the hosts present in another network then this is called direct broadcasting.

If the destination IP address is then to transmit data, all the hosts present in this network sender will send the data to the address

You're presumably already acquainted with the loopback address, often known as localhost. It is a local system's internal address and routes there. In IPv4, the loopback address is 127.0.01. The loopback address in IPv6 is either 0:0:0:0:0:0:1 or::1.

In computer networks, the range for loopback addresses is to The loopback address is used by the operating system to test the software in the local machine.

When the destination is a loopback address for any packet, then the message is received by the same machine as it is destined to itself.

The most common use of loopback addresses is to recognize the device on the network.

IP address

The full form of IP is “Internet Protocol”, which means set of rules for the internet. The IP address is a numerical value that is unique, and it represents the unique node(computer) in the network.

IP addresses are classified in two types:

  1. IPV4
  2. IPV6

In IPV4, the number of bits is 32 which are divided into 4 parts by dots. For example a.b.c.d is a generalized IPV4 address where values of a, b, c and d can vary from 0 to 255.

For example is an IPV4 address.

In IPV4 address number is represented in decimal form.

In IPV6, the number of bits is 128. IPV6 is more advanced and it has more addresses than IPV4. IPV6 numbers are represented in hexadecimal form.

In IPV6 colon is used as a separator between addresses.

For example fd80::c3a8:6435:d2d8:d9f3b01 is an unique IPV6 address.