Question

In a sliding window ARQ scheme, the transmitter's window size is N and receiver's window size is M. The minimum number of distinct sequence numbers required to ensure correct operation of the ARQ scheme is

• A. max (M, N)
• B. M + N
• C. MN
• D. min (M, N)

Answer 1

The correct option is B M + N

In sliding window protocol :
Minimum number of sequence number = M + N
Since at any time number of unacknowledged frames are M at receiver and same time N packets are transmitted by sender.
So, M+N $\le$ minimum sequence number.