Fiddler – Connection Simulator

Requires Fiddler 2

This add-on for Fiddler 2 Proxy, allows for simple emulation of bandwidth constraints. This configuration can be used to limit and dynamically vary the available bandwidth for download. The result of this can be plotted n to a chart showing the parameters and average bandwidth speed per request.

The need arose for the ability to simulate bandwidth constraints and misbehaviour in various projects I have been testing. I could find no simple tool that could provide basic simulation without the need to created and configure a virtual platform.

When searching for tools, I come across Fiddler and observed that the product could be extend using is API’s. I decided to use the fiddler engine and create and add-on that could approximately simulation connections and various types of connection behaviour.

The simulator is not 100% accurate and as such behaves in a more realistic manner givent he fact that no two connections are identical.

Features

Fully configurable via the fiddler command line (type: “simulate help” in the command window for details).

Integrated Menu.

  • Fully configurable via dialogue from the menu.
  • Configuration is saved/persisted between sessions.
  • Supports 4 emulation modes:-
    • Flat – A fixed bandwidth limit is applied.
    • Curve – the bandwidth constraint is applied in a curved pattern up to n% below and above the midpoint. The step for each request in the curve can be defined.
    • Sawtooth – Bandwidth climbs to a maximum of n% above the midpoint and then drops to n% below the midpoint and then starts to increase again. The step for each request in the curve can be defined.
    • Random – the bandwidth allowed fluctuates randomly in a range +/- n% of midpoint.
  • Supports connection error (404) generation:
    • Create regular connection errors (i.e. every n requests)
    • Create random connection failures.
    • Disable connection (every request is a 404).
  • All data applied to a request is store in the custom column in Fiddler. This data is then stored with any saves sessions.
  • Visualisation of session response bandwidth is provided by a line chart. Major functions are:-
    • Data is loaded from the session log meaning visualisation can be regenrated from saved sessions.
    • The chart has pull pan and zoom support.
    • The chart supports copy, save as image and printing.
    • Hovering over a data point will display data relevant to the associated request (URL and throughput).
    • double Clicking on a data point will display extended data relevant to the associated request (URL, etc).
  • Visualisation of overall bandwidth (response or request) is provided by a column chart. Major functions are:-
    • Data is loaded from the session log meaning visualisation can be regenrated from saved sessions.
    • The chart has pull pan and zoom support.
    • The chart supports copy, save as image and printing.
    • Hovering over a data point will display data relevant to the associated request (URL and throughput).
    • double Clicking on a data point will display extended data relevant to the associated request (URL, etc).

Future Improvements

Support for upstream (request bandwidth) constraints.

Support for fixed length request and response latency.

Downloads

Versions 2012.0.0 – Download

Archived Versions

Versions 2011.0.0 – Download

Credits and Links

Thanks to ZedGraph for the charting component used in this product.

Screenshots

The configuration window.

Visualisation

4 Responses to "Fiddler – Connection Simulator"

  • Psk says:
    • Logic Worx says:
Leave a Comment