Recording Loadrunner Traffic in Fiddler

It can be useful to capture loadrunner http traffic in fiddler.  This can be useful, for example, for seeing the timeline of http requests, which ones are slow, what sort of parallelism exists, if any, etc.  It can also be useful to compare the vugen timeline of requests to the same information captured directly from the browser, as vugen may not match browser behavior as expected, by serializing what is sent asynchronously in parallel by the browser, etc.

Vugen can be configured in Runtime Settings, Internet Protocol, Proxy, Use Proxy Server, address=localhost, port=8888.

You then put breakpoints in the script before and after the section you want to record, run the script in vugen to the first breakpoint (with logging disabled), start capturing traffic in fiddler, run the script to the second breakpoint and stop capturing traffic in fiddler.  You can then see a visualization of the request pipeline in fiddler for your loadrunner traffic:

It is also a good idea to capture the traffic by running the script from the controller on the load generator to reduce vugen overhead.  You will get a more compact and realistic pipeline that way.

You can then record the same transaction manually using the web browser for comparison to loadrunner.