0 votes 0 votes The minimum frame length (in bytes) of the cable of length 240 meter for transmitting data at a rate of 500 Kbps in IEEE 802.3 LAN is __________. (Assume the signal speed in the cable to be, 2,00,000 m/s) Computer Networks made-easy-test-series computer-networks lan-technologies + – _jerry asked Feb 1, 2018 • edited Mar 5, 2019 by Aditi Singh _jerry 738 views answer comment Share Follow See all 10 Comments See all 10 10 Comments reply braindead commented Feb 1, 2018 reply Follow Share I think the min frame length in 802.3 i.e Ethernet is 46 Bytes. So other info is not required maybe. What is the ans? 0 votes 0 votes _jerry commented Feb 1, 2018 reply Follow Share Yes, the answer is 46 Bytes. But, are we supposed to remember that? Please solve this by using the values. 0 votes 0 votes braindead commented Feb 1, 2018 reply Follow Share There's no solving involved. If u remember the frame structure in LAN u can derive this val 0 votes 0 votes sourav. commented Feb 1, 2018 reply Follow Share I agree that minimum data size in ethernet is $46 Byte$ but calculating using formula by using the given parameters $150B$ is coming as answer. 0 votes 0 votes Ashwin Kulkarni commented Feb 1, 2018 reply Follow Share Actually min frame data is 46B and min frame length by adding checksum and addresses it would be 64B in ethernet! But for these values 150B is coming 0 votes 0 votes _jerry commented Feb 2, 2018 reply Follow Share Sorry for stating the wrong answer previously. The answer is 150 bytes. But how is this solved? 0 votes 0 votes braindead commented Feb 2, 2018 reply Follow Share lol _jerry, why did u say yes? haha In LAN the transmission delay should be at least twice the propagation delay(to detect collisions) Therefore, Tt >= 2*Tp i.e. L/B >= 2* Tp L >= 2 * (dist/speed) * Bandwidth L >= 2 * (240/200000) * 500000 L >= 1200 bits L >= 1200/8 Bytes Thus min length = 150 B 0 votes 0 votes braindead commented Feb 2, 2018 reply Follow Share If the options have both 150B and 46B, what should we choose? 0 votes 0 votes Ashwin Kulkarni commented Feb 2, 2018 reply Follow Share Ofcourse 150B. Because min payload size is 46B and min frame length will be 64B 2 votes 2 votes _jerry commented Feb 2, 2018 reply Follow Share @ braindead...Thanks. Arey, I got confused yaar! There was some other question that I was doing at the same time for which the answer was 46 bytes. :p 0 votes 0 votes Please log in or register to add a comment.