Doubt regarding Go Back n

Question

What is 'n' in Go back n protocol
Is it the number of bits required in total sequence numbers or is it the total sequence numbers?

​​​​Please explain

Comments

that is the window size of sender https://en.wikipedia.org/wiki/Go-Back-N_ARQ

Answer 1

Assume  ,sequence bits : m=3

Sender window size is 7 (SWS < 2^m) and could contain sequence no. 01234567 

Assume buffer is 012345670123456701234567....

On transmission , we send group of seq no#s 

0123456

Here if

 0 recieved successfully

1 recieved successfully

2 received successfully

3 is lost  

4 recieved 

5 received

6 recieved  

Then , sequence numbers In buffer from 3456701 (SWS=7)will be send again. As seq # 456  will be discarded by the receiver because Receiver window size is always 1 & accepts inorder only.

Now buffer will be 3456701234567012345...

Seq#   3456701 send again 

​​​​​​hence, N in goback N denotes the window size because

1. maximum N retransmissions could take place (if very first frame is lost )

and  

2. it can transmit N frames to the peer before requiring an ACK.

correct me if I am wrong!

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