Station A uses 32 bytes packets to transmit to station B using a sliding window protocol.The round trip delay between A and B is 80ms and bottleneck bandwidth on path between A and B is 128 kbps. What is the optimal window size that A should use?(GATE-2006)
Ans : 40
The distance between two stations M and N is L kilometers.All frames are K bits long.The propagation delay per kilometer is t secs . Let R be the channel capacity (bits/sec) Assumimg processing delay is negligible the minimum number of bits for the sequence number field in a frame for maximum utilization , when the sliding window protocol is used is : ? (GATE -2007)
Ans : log ( 2LtR +K / K )
1) For 2nd question what they mean by swp is it GBN or SR ?
2) What is the window size ? Is it 2a or 1+2a?
If suppose window size is 2a and swp they mean is GBN then ASN = 1+2a
Using 2a and log (ASN ) gives correct answer for both questions.
Any reason for the above ?
Thank you