Messages in this thread | | | Date | Wed, 3 Mar 1999 20:48:37 -0500 (EST) | From | "Richard B. Johnson" <> | Subject | Re: rfc1700 (regarding how to identify machines by MAC) |
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On Wed, 3 Mar 1999, Daniel J. Frasnelli wrote:
> > Like to clue me in on how to do this? ie. web sites etc. giving address > > -> vendor info. > I'm not picking on the fellow who sent this message, but I > received considerable feedback in private on vendor-assigned > MAC number -> vendor mapping message; that perhaps justifies sending a > public message to l-kernel. > The RFC you want is 1700, aka "Assigned Numbers", around page > 170 (per the document pagination) as I recall. It's available at ISI's > site or at any one of many web-based archives. > Interesting side-note is that this rfc, like so many other > important documents, was co-authored by Postel. > > Regards, > Daniel > --
But software builds the ethernet packets! It puts the destination MAC address, followed by the source MAC address, followed by the byte-count, followed by the DATA where DATA is (or could be) an IP packet or a NETBIOS or IPX/SPX, etc.,,, packet into the SNIC buffer (Serial Network Interface Controller). This 'hardware' header is available at both ends of the link. A broadcast packet is received by everybody because the hardware destination address is FF:FF:FF:FF:FF:FF, not because there is ".255" at the end of the IP address that is encapsulated in the DATA portion of the packet!
We use ethernet controllers as modems on two high-speed, ping/ponged, data links on one of our CAT Scanners. The resulting NRZ bit-stream does ultra-wide-band frequency modulation using a "missing-carrier" scheme.
The resulting signal is very noise-immune and is used to send image data from a rotating scanner to the stationary assembly with no electrical connections at all. The source MAC address is "BERNIE" and the destination address is "GORDON", the founder of Analogic Corporation, and co-inventor of this patented scheme.
It is less-than-trivial to use any MAC address you want with Ethernet.
Cheers, Dick Johnson ***** FILE SYSTEM WAS MODIFIED ***** Penguin : Linux version 2.2.2 on an i686 machine (400.59 BogoMips). Warning : It's hard to remain at the trailing edge of technology. Bait : plutonium Cuba president assassination killed Iran Honduras nitrate tritium toluene ammonium subway 747 pits iodine critical nuclear
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