Sliding Window Protocol

Sliding windows protocol works as follows:

1. Sender sends a fixed number of frames without acknowledgments.
2. Each frame is labelled with a sequence number.
3. On getting acknowledgments from the receiver.
4. Sender sends more frames.
5. Each acknowledgement is labelled with a respective frames sequence number.

Precautions:

There should not be duplicate sequence numbers.

Example of Sliding window protocol;

Window size is 7.

Sender can transmit 7 frames without acknowledgement.

Frame no. 1,2,3,4,5,6,7.

1

2

3

4

6

7

8

9

10

11

Now sender transmit 4 frames and received an acknowledgment that thefirst 3 frames are successfully received.

1

2

3

4

6

7

8

9

10

11

The window will slide forward by three frames.

1

2

3

4

5

6

7

8

9

10

Now sender will cover next 7 frames.

Frame no. 4,5,6,7,8,9,10.

Which looks like windows is sliding from left to right.