Generating Pause Frames to test hardware

Question

I have put together a media converter that converts from 100Mbps ethernet on one side and 100BASE-FX fiber on the other. The application that this converter goes into uses Full Duplex / Pause Frame flow control to handle data overloads. I have configured my hardware to accept and deal with pause frames. What I need is a means of testing the setup to see that the media converter correctly handles the pause frames. To that end I have 2 questions....

1) Does anyone have a good method for testing a piece of hardware for it's handling of pause frames?

2) An idea that I had was to send data through the converter. While doing so, send a pause frame of a known length to the converter. Then look to see that the device pauses for the correct amount of time. Does this method seem plausible? If so, is there an easy way (software tool) to generate pause frames to accomplish what I am trying to do?

Any help here would be greatly appreciated.

Thanks, Mike Nycz

Answer 1

There are two types of Pause frame testing:

1) Your device should detect Pause frames and stop transmitting for the time mentioned in received Pause frame. If you send a few pause frames to your device, it can be difficult to detect whether your device stopped transmission for that small duration. What you can do is to send Pause packets continuously. By doing this your device should altogether stop transmitting till it is receiving pause packets.

2) Your device should generate Pause frames when RX FIFO level is above a certain threshold and should stop generating them when level again goes below the threshold.

You can use a Packet generator like N2X/IXIA etc for generating pause packets. One more thing Pause packets should be of 64 bytes only. For size other than 64bytes, device may opt to reject them.