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Ethernet on recent FPGAs

(snip)

Higher than the actual clash rate on the current system?

I have heard stories about NICs produced with the same address, most likely in the same batch with a high probability of being installed on the same net.

We once had a Sun system that the local computer hardware people sent back to Sun to be fixed. The rule at the time was that one should remove the ROM (or battery backed RAM) before sending it in. In this case, it was reinstalled backwards destroying the stored address. Losing the stored address from battery backed RAM can't be that uncommon. (The battery life tends to be less than the processor life.)

Also, I once knew a net with a device with address 00:00:00:00:00:00. As there was only one, it was decided to leave it alone.

-- glen

Reply to
glen herrmannsfeldt
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Nico Coesel wrote: (snip)

As the subject is FPGAs, I believe it isn't hard to change data in a synthesized ROM after the bit file has been generated. That should be pretty convenient for generating the packet. Getting the IP address is a little harder.

Not so much network errors as administration problems. It is harder to track down devices with variable MAC addresses.

-- glen

Reply to
glen herrmannsfeldt

Costs $1,650 for 16,777,216 unique addresses.

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-hpa

Reply to
H. Peter Anvin

A bigger issue is that randomness is frequently a premium resource in real-life systems.

-hpa

Reply to
H. Peter Anvin

The intent was never to have MAC addresses generated at random *in the field*, i.e., upon interface initialization. The idea was to generate them at random in the *manufacturing process*; there would not be "variable" MAC address for a given device over time. We only wanted to avoid the OUI administration problem.

-- Rich Seifert Networks and Communications Consulting 21885 Bear Creek Way (408) 395-5700 Los Gatos, CA 95033 (408) 228-0803 FAX

Send replies to: usenet at richseifert dot com

Reply to
Rich Seifert

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