Whiledeveloping an ethernet analyzer I was working around with the ethernet gigabit diagnostics registers (RDFT, RDFH, PBM) with a 82541 PCI Adapter and found, that the real frame data are always stored 8 Bytes after the RDFT location. At a closer look to these 8 Bytes I found the first 2 Bytes providing the frame size. Following of 2 bytes containing some magic frame information, following 4 bytes set to 0. Basically the first 2 Bytes are very helpful to keep track of the PBM (Packet Buffer) frames, I like to know the meaning of the 6 following bytes.
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