How to verify network bandwidth issue in web application

I am maintainign a ASP.NET app. Some of users action are pretty slow; one 开发者_JAVA技巧of my colleagues claim it is caused by network bandwidth as some used dll will connect over to internet to get data.

How could I verify it's really due to network issue? Any tools can peer the network connection during the process?

Thanks.

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I would implement tracing - enable remote tracing on the server

<configuration>
  <system.web>
    <trace enabled="true" requestLimit="40" localOnly="false"/>
  </system.web>
</configuration>

and then modify the code that calls the DLL in question, include this code before and after call:

Trace.Write("Calling dll " + DateTime.Now.ToString());

and after

Trace.Write("Finished calling dll " + DateTime.Now.ToString());

then hit the page that's slow, and after that go to http://yourserver/Trace.axd and look at the last aspx request

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If you think the "network issue" is on the server side then you could just use TaskManager andswitch to the network tab to see the bandwidth utilization. If the utilization is close to the bandwidth you have at your server's end then you'll know for sure.

The same can be done if you suspect the user doesn't have enough bandwidth.

FYI: If you are making additional internet calls (either from the client or the server) there will be additional network latency that you'll get (for each call). That doesn't indicate a bandwidth issue but just that there are additional network latency issues to deal with.