5 votes 5 votes In Go-Back-N protocol, if the maximum window size is 127, what is the range of the sequence number? A. 0 to 127 B. 0 to 128 C. 1 to 127 D. 1 to 128 Answer given is A Please explain :) Thanks. Computer Networks computer-networks go-back-n sliding-window + – sunil sarode asked Oct 6, 2017 sunil sarode 13.6k views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
Best answer 11 votes 11 votes Here in Go Back - N : N refers to the senders window size So window size here = 127 as it is Go back - 127.. But we know number of distinct sequence numbers for Go back N = max senders window size + 1 = 128 And starting sequence number = 0.. Hence range of sequence numbers = 0 to 127 Habibkhan answered Oct 6, 2017 • selected Oct 6, 2017 by sourav. Habibkhan comment Share Follow See all 7 Comments See all 7 7 Comments reply Show 4 previous comments Nandkishor Nangre commented Sep 19, 2018 reply Follow Share is this approach correct there window size is 127 so numbering is from 0 to 126 = 0 to (2^n)-1 so, (2^n)-1=126 2^n=127 so, n=7 now, the actual range will be 0 to (2^n)-1 == 0 to (2^7)-1 i.e= 0 to 127 0 votes 0 votes vupadhayayx86 commented Jan 6, 2019 reply Follow Share @Nandkishor Nangre 2^7 is 128 not 127 0 votes 0 votes mehul vaidya commented Dec 7, 2019 reply Follow Share why sequence number must start from 0, here D can also be correct 0 votes 0 votes Please log in or register to add a comment.
1 votes 1 votes Sequence number >= sws+rws for any protocol.. If you go through gbn rws=1 Therefore seq n >= 127+1 Therefore the range would be from 0 to 127 vamp_vaibhav answered Oct 6, 2017 vamp_vaibhav comment Share Follow See 1 comment See all 1 1 comment reply Pratik Mishra commented Dec 5, 2017 reply Follow Share Since 128 sequence numbers are there, then option d can also be the answer or is it that the sequence numbers start from 0 always? 0 votes 0 votes Please log in or register to add a comment.
0 votes 0 votes https://stackoverflow.com/questions/28444055/go-back-n-window-size Please refer this it should clear all doubts vupadhayayx86 answered Jan 6, 2019 vupadhayayx86 comment Share Follow See all 0 reply Please log in or register to add a comment.