Discuss about the various flow control and error control protocols in data link layer as well as their window size, range of sequence numbers
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Flow Control is one important design issue for the Data Link Layer that controls the flow of data between sender and receiver.
In Communication, there is communication medium between sender and receiver. When Sender sends data to receiver then there can be problem in below case :
1) Sender sends data at higher rate and receive is too sluggish to support that data rate.
To solve the above problem, FLOW CONTROLis introduced in Data Link Layer. It also works on several higher layers. The main concept of Flow Control is to introduce EFFICIENCY in Computer Networks.
Approaches of Flow Control
Feed back based Flow Control
Rate based Flow Control
Feed back based Flow Control is used in Data Link Layer and Rate based Flow Control is used in Network Layer.
Feed back based Flow Control
In Feed back based Flow Control, Until sender receives feedback from the receiver, it will not send next data.
Types of Feedback based Flow Control
A. Stop-and-Wait Protocol
B. Sliding Window Protocol
A One-Bit Sliding Window Protocol
A Protocol Using Go Back N
A Protocol Using Selective Repeat
A. A Simplex Stop-and-Wait Protocol
In this Protocol we have taken the following assumptions:
It provides unidirectional flow of data from sender to receiver.
The Communication channel is assumed to be error free.
In this Protocol the Sender simply sends data and waits for the acknowledgment from Receiver. That's why it is called Stop-and-Wait Protocol.
This type is not so much efficient, but it is simplest way of Flow Control.
In this scheme we take Communication Channel error free, but if the Channel has some errors then receiver is not able to get the correct data from sender so it will not possible for sender to send the next data (because it will not get acknowledge from receiver). So it will end the communication, to solve this problem there are two new concepts were introduced.
TIMER, if sender was not able to get acknowledgment in the particular time than, it sends the buffered data once again to receiver. When sender starts to send the data, it starts timer.
SEQUENCE NUMBER, from this the sender sends the data with the specific sequence number so after receiving the data, receiver sends the data with that sequence number, and here at sender side it also expect the acknowledgment of the same sequence number.
In Communication, there is communication medium between sender and receiver. When Sender sends data to receiver then there can be problem in below case :
1) Sender sends data at higher rate and receive is too sluggish to support that data rate.
To solve the above problem, FLOW CONTROLis introduced in Data Link Layer. It also works on several higher layers. The main concept of Flow Control is to introduce EFFICIENCY in Computer Networks.
Approaches of Flow Control
Feed back based Flow Control
Rate based Flow Control
Feed back based Flow Control is used in Data Link Layer and Rate based Flow Control is used in Network Layer.
Feed back based Flow Control
In Feed back based Flow Control, Until sender receives feedback from the receiver, it will not send next data.
Types of Feedback based Flow Control
A. Stop-and-Wait Protocol
B. Sliding Window Protocol
A One-Bit Sliding Window Protocol
A Protocol Using Go Back N
A Protocol Using Selective Repeat
A. A Simplex Stop-and-Wait Protocol
In this Protocol we have taken the following assumptions:
It provides unidirectional flow of data from sender to receiver.
The Communication channel is assumed to be error free.
In this Protocol the Sender simply sends data and waits for the acknowledgment from Receiver. That's why it is called Stop-and-Wait Protocol.
This type is not so much efficient, but it is simplest way of Flow Control.
In this scheme we take Communication Channel error free, but if the Channel has some errors then receiver is not able to get the correct data from sender so it will not possible for sender to send the next data (because it will not get acknowledge from receiver). So it will end the communication, to solve this problem there are two new concepts were introduced.
TIMER, if sender was not able to get acknowledgment in the particular time than, it sends the buffered data once again to receiver. When sender starts to send the data, it starts timer.
SEQUENCE NUMBER, from this the sender sends the data with the specific sequence number so after receiving the data, receiver sends the data with that sequence number, and here at sender side it also expect the acknowledgment of the same sequence number.
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