A gentleman today wondered if his expensive leased fibre line was causing packet loss, even though he compared it with an ADSL line from the server to the host. As Dennis Rockwell of BBN pointed out “What you have discovered is that your 2Mbps link is not the bottleneck; that lies elsewhere in your network path. The extra bandwidth of the fiber link cannot help this application”.
Dennis is correct. But how do you know where to look to fix the problem? Here’s a little story from a manager of international datacenters in Japan and the US to illustrate how complicated the issue can become…