MAC address confusion

Saku Ytti saku+nanog at ytti.fi
Wed Mar 4 02:48:48 CST 2009


On (2009-03-03 13:50 -0800), Kevin Oberman wrote:

> This is only a problem if you have multiple systems running DECnet (or
> some other protocol using this) with the same layer 3 address. That
> should never happen, so there should be no duplication.

Why would they need to have same L3 address? The way I see it, only thing that
matters is, if or not, the addresses might speak ethernetII. If your ethernetII
switch sees your local 02 address and one of the addresses below and they
collide, the switch will keep relearning the address behind two ports. Unless
of course it is guaranteed, that none of these addresses will ever appear as
BIA in ethernetII capable NIC.

02-07-01   (hex)		RACAL-DATACOM
02-1C-7C   (hex)		PERQ SYSTEMS CORPORATION
02-60-86   (hex)		LOGIC REPLACEMENT TECH. LTD.
02-60-8C   (hex)		3COM CORPORATION
02-70-01   (hex)		RACAL-DATACOM
02-70-B0   (hex)		M/A-COM INC. COMPANIES
02-70-B3   (hex)		DATA RECALL LTD
02-9D-8E   (hex)		CARDIAC RECORDERS INC.
02-AA-3C   (hex)		OLIVETTI TELECOMM SPA (OLTECO)
02-BB-01   (hex)		OCTOTHORPE CORP.
02-C0-8C   (hex)		3COM CORPORATION
02-CF-1C   (hex)		COMMUNICATION MACHINERY CORP.
02-E6-D3   (hex)		NIXDORF COMPUTER CORPORATION

-- 
  ++ytti




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