Hello, everyone welcomes to the course on computer networks today we shall see Network protocols and communication before we step into the topic we shall understand.
What are the things we are going to learn today?
We will be learning about
- Data communication of Network protocols
- Data flow
The protocol is very important in a computer network.
Understand guys protocols are very important in the computer network.
- What are the elements that will also be addressed in today’s session now we shall see?
- What is data communications?
Data communications are the exchange of data between two nodes if there are two nodes they are going to exchange data.
Via some form of link or transmission medium, in this case, the transmission medium is the cable we have seen data communication.
It means two nodes are going to exchange data flow means the data is going to flow from one node to another node.
There are three different flows in Network protocols and communication:
- Full duplex
We shall see all these three data flows in detail.
Data simplex Network protocols and communication
- The simplex is always unidirectional.
- Communication one node can transmit and others will receive.
For example keyboards, traditional monitors.
keyboards just take a keyboard that is connected to a CPU.
The keyboard is going to give data to the CPU.
Whereas CPU is not going to give any data to the keyboard.
Likewise, our traditional monitors.
I am NOT talking about our touch monitors are traditional monitors.
Whatever the data is there in the CPU.
That is going to be given to the monitor and the monitor is not going to give any information to the CPU in both the cases.
Data or communication is always unidirectional.
The communication is in both directions.
It means it can send as well as it can receive.
But not at the same time.
The very important part about half-duplex is that communication can happen in both directions.
Not at the same time if one device is sending the other device can receive.
And not at the same time both sending and receiving can happen.
For example walkie talkie in a walkie talkie, we can talk as well.
As we can but we can’t talk and listen at the same time.
Now we shall see:
What is full-duplex or simply duplex in the previous case.
That is the half-duplex communication that happened in both directions.
Duplex or Full Duplex
But not at the same time whereas in full-duplex communication can happen in both directions simultaneously.
It means devices can send or receive data at the same time.
Example: telephone line
We can talk as well as listen simultaneously in a telephone line.
Now we shall see an example:
Simplex communication now this computer is sending data in only one direction.
So this is simplex if both sending and receiving can happen.
But not at the same time if you observe now sending is happening now receiving is happening.
Not at the same time, this is sending and this is receiving.
This is not happening at the same time.
So this comes under the half-duplex and full-duplex mode of communication.
Both sending and receiving can happen at the same time if both sending and receiving can happen simultaneously.
Then we call as full-duplex we will now see.
What are the protocols in any communication scheme?
We always have certain things in common.
- The source or sender
- Destination or the receiver
- Channel or media any communication.
Will definitely have these things source or the sender destination.
The receiver channel or the media and this communication will always be governed by certain protocols.
So protocols are rules that govern all the methods of communication.
What if there are no protocols?
If this first guy speaks at high speed.
Which this destination cannot handle this communication.
It becomes useless so they have to mutually agree upon certain rules.
What if the first guy speaks in the language
which the second guy cannot understand.
He may be grammatically correct.
But still, there is no use in this communication again.
What if the first guy keeps on talking at a high speed at the same time.
Not at all giving any room for the second guy to respond.
So these are example situations.
Where the communication goes chaos or messy.
So definitely there is a need for protocols.
Because a protocol is a set of rules.
That governs data communication simply speaking protocol is a rule that governs data communication.
- What is communicated in the network?
- How it is communicated in the network?
- When it is communicated in the network?
Before going into the network communication.
Let’s talk about
Protocols – Human communication
Protocols are necessary for human communication.
Definitely there should be:
- A sender and a receiver
There may be a single receiver or a group of receivers.
And this human communication can be effective.
When this communication involves.
- Common language and grammar
Otherwise, communication will not be perfect.
- Speed and timing of delivery
The speech is also very important in human communication.
If the first guy wants to ensure whatever he has talked is understandable by this second guy.
He should get confirmation or the acknowledgment from the receiver that is the destination only then human communication can be effective.
We have just seen
- What is human communication?
- Why do we need protocols in human communication?
- Why do we need protocols in network communication to say?
If there is a sender and there is a receiver and this communication can be effective when these protocols are addressed properly the message.
Should be encoded formatted and encapsulated in such a way.
That the destination can understand timing.
Also very important in network communication the size is also very important.
Because the link cannot carry big data if this is a low capacity link.
Then this link cannot carry big data if there is very big data on the sender side it cannot send that big data on a very small link.
So it has to be handled appropriately at the same time the delivery option.
It should also be dealt with whether the message is only for one destination.
Some groups of destinations on all day nations in the network.
That should also be dealt with in the protocol spot.
A protocol defines
- Message encoding
- Message formatting and encapsulation
- Message size
- The delivery options
What exactly call as elements?
The elements of the protocol:
1. Message encoding
message formatting and encapsulation, message timing, message size, and message delivery options.
We shall see each of these elements in a detailed manner message encoding.
This means the source that is the source computer generates a message.
It gives that message to the encoder in order to generate signals once the data is converted into signals.
Now it is given to the transmitter for the transmission.
You may be getting confused about why we need encoder here.
Because we have two kinds of transmission medium one is a wired medium another one is a wireless medium the source has to understand.
Which medium it is connected to?
If it is a wired medium the data have to be converted into signals in order to facilitate the data transmission on a wired medium.
It is a wireless medium the sender has to encode the data in the form of waves.
Because this is a wireless medium we can’t send signals.
We have to send waves and once the data is sent through the transmission medium.
The receiver receives the data and D course it decoding means understanding.
It after understanding properly it means the message has reached the destination.
What message encoding is all about the sender sends the data.
The sender creates the data and encodes the data.
And finally, the transmitter sends the data through the transmission medium.
This transmission medium takes the data to the receiver after receiving the data.
It decodes the data and after proper decoding,
It means the message has reached the destination.
What message encoding is all about.
We shall see the second element of the protocol.
2. Message formatting and encapsulation
Both the sender and the receiver.
Must mutually agree upon certain formats.
- Which we call as formatted at the same time?
- When the receiver receives some data?
It should identify who has sent this data.
We are going to add some information with the data in order to identify the sender and the receiver.
So we are not going to just send data assets.
We are going to encapsulate certain things.
Like the source information and the destination information with the data.
That the right sender and the receivers are identified.
3. Message sizing
If there is a very big message to be communicated.
To the destination, human breaks the message into smaller parts or sentences.
Say above the picture if the first guy has very big content to be sent.
So what he does he breaks the message into smaller parts or sentences likewise our computer.
We should also do that if the capacity of the link is very small.
But the data to be transmitted is very big.
This computer should break this big message into smaller units.
Which this transmission medium can handle
This is what message sizing and this is one of the things a protocol.
4. Message timing
The fourth element of protocols
And message timing deals with flow control and response time mode.
Let’s first talk about flow control.
Assume the first guy is very fast the sender is very fast.
And the receiver is slow since the sender is very fast it can send data at high speed.
What about the receiver he can’t handle that speed.
If there is no flow control mechanism he can keep so on sending data.
But he cannot receive that data so the entire communication will become useless.
It is the responsibility of the protocol to provide a flow control mechanism at the same time.
The sender is sending some data and the receiver has to acknowledge.
The data when the acknowledgment is sent back to the sender can understand that the data is received by the destination.
If the acknowledgment is not received.
The sender has to wait for a certain period of time after the expiry of the time.
The sender will retransmit the same.
So that we can ensure guaranteed delivery and it is the responsibility of the protocol.
To tell how much time this computer should wait for an acknowledgment.
And we have the last element of the protocol.
5. Delivery options
There are three delivery options:
Unicasting means one sender and one receiver.
It means this sender is going to send data to exactly one receiver in the network.
If the sender is sending the data to exactly one destination it is called unicasting.
The sender sends the data to the set of receivers.
But not to all then this is multicast in broadcasting.
The sender sends the data to all the participants in the network.
Then we call us broadcasting and that’s it guys now we shall just recapture.
what we have seen today?
We have seen:
What is data communication?
That is the exchange of data between nodes.
And we have also seen what is data flow.
We have seen the three data flows:
We have also seen the role of protocols in computer networks.
Not only in computer networks even in real-time protocols has a very important role to play with and we have also seen.
- What are the elements of protocols?
There are five elements of protocols:
- Formatting and encapsulation
- Messaging size
- And finally the delivery options
I hope you understand the session what is Network protocols and communication, informative to thank you all.