While diagnosing your network because of performance issues, if you do determine that the network is not meeting technical expectations, you should isolate the source of the problem and diagnose the problem on that device. Whireshark is a cool tool to find out the root cause of a network performance issue. So, if i were to answer to the following question : which tool among many comes into your mind to pinpoint the root cause of a network performance issues ? I would have given the following answer : WIRESHARK.
