1 votes 1 votes The round trip delay between A and B is given as 60 ms, and the bottleneck bandwidth of the link between A and B is 512 KBps. What is the optimal window size (in packets) if the packet size is 64 bytes and the channel is full duplex. Computer Networks made-easy-test-series computer-networks data-link-layer ethernet + – LRU asked Jan 20, 2022 LRU 532 views answer comment Share Follow See 1 comment See all 1 1 comment reply Chandrabhan Vishwa 1 commented Jan 20, 2022 reply Follow Share ans should be 480 here given RTT so never add one for frame transsmission time 0 votes 0 votes Please log in or register to add a comment.
1 votes 1 votes @LRU Optimal window size =(1+2a) where a =Tp/Tt ….. Full duplex link, so window size = 2* Tp * Band Width = 60 * 10-3 * 512*103 =30720 bytes… packet size = 64 bytes... window size in terms of packets = 30720 / 64 = 480…. optimal window size = 480+1= 481 ... 1. https://gateoverflow.in/144462/Cn-optimal-windows-size aaa 1 answered Jan 20, 2022 aaa 1 comment Share Follow See all 3 Comments See all 3 3 Comments reply Isha_99 commented Jan 21, 2022 reply Follow Share @aaa 1 Why you added 1 to 480 ? 1 votes 1 votes Vishal_kumar98 commented Jan 21, 2022 reply Follow Share We have to consider the receiver's end as well or not? Like we are fine with only sender's window size. Please elaborate this. 1 votes 1 votes aaa 1 commented Jan 21, 2022 reply Follow Share @Isha_99 @Vishal_kumar98 optimal window size is when link utilization is 100% … To find optimal window size for sender , we consider N=1+2a =>( N/1+2a) = 1 ..… where N = sender window size and a = Tp / Tt .. Given, RTT between x and y as 60 ms = (60 * 10-3 ) seconds and bandwidth of link between X and Y is 512 KBps = (512 * 103 ) Bytes/seconds…. It is Full duplex channel, so total data send from x to y is = (2* Tp) * Band Width = RTT * band width =( 60 * 10-3) * ( 512 * 103) = 60 * 512 = 30720 Bytes…. ## packet size = 64 bytes... ### Number of window require = 30720 / 64 = 480 ... @@@ So optimal window size is N = 1+2a = 1+480 = 481.... In case optimal window size, we can indirectly say that maximum throughput should be achieved. It means link utilization is 100% in case of optimal window... And as you said , window size is defined as number of frames sent in 1 RTT--> This is window size in terms of packets .... we can say , optimal window size is 1 greater than number of frames send in 1 RTT . See this thread also https://gateoverflow.in/107261/optimal-window-size … 1 votes 1 votes Please log in or register to add a comment.