Underrun in open_eth

I am now running on a NEEK using the Igor MAC to connect to ethernet with a National PHY.

My MAC is configured as follows in HW:

Descriptors:128

Transmit buffer: 2048B

Receive buffer: 4096B

I can ping TO outside, and I can ping FROM outside but...

When I allow ping to use its default packet size, I *always* get errors like this:

oeth: tx14,00a34900

This seems to be sensitive to the packet size, since when I "ping <ip> -s 5", resulting in a 5 byte payload, the problem gets better(still happens sometimes). When It does happen, the interface is pretty hosed up, and doesn&#39;t really respond anymore.

When I looked into open_eth.h, I found that errors are reported in the low 9 bits of the bdp structure (which I don&#39;t really understand B.T.W....first time in this code).

The above code corresponds to OETH_TX_BD_UNDERRUN

Can anyone tell me what this means, and why I may be seeing it?