MAC Address Chips

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I'm looking for "silicon serial number" type chips to give a unique
MAC address for ethernet. I'm aware of the Dallas one-wire parts, but
what i'd really like is an I2C/SMBus/TWI type solution. Or SPI.

I don't want to buy a block of MAC addresses from the IEEE and program
EEPROMs during production. So I want guaranteed unique 48-bit numbers
that don't clash with allocated MAC addresses.

Cheers
TW

Re: MAC Address Chips
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Dallas actually tried to make serial number chips pre-programmed with
valid globally assigned MAC address a number of years back, but
were blocked by IEEE.

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If you are comfortable using locally assigned MAC address
(see http://www.certsoft.com/mac.htm ) what I've done in one unit
is use the lower 32 bits from a Dallas serial number chip (unfortunately,
one wire bus) combined with a a fixed, 16 bit locally assigned prefix
as the upper 16 bits of the MAC. It's a judgement call.

Re: MAC Address Chips
Those IEEE guys are real humps with those MAC addresses.

A couple years back a fellow was trying to do a public service for people
who
couldn't afford the thousands of dollars to buy a block, and bought a block
he
was going to divide up and sell small groups at cost.

The IEEE got on his case, yet they won't sell small blocks themselves.

Dirtbags.

The only choice you have to get unique IDs is to find a batch of
discarded/obsolete network cards and use those IDs.  Make sure
to destroy the card to guarantee uniqueness.

Rufus


Here's a "what if":

Suppose someone set up a company that builds network cards. Customer
makes a down payment on a batch, requesting the MAC id's in advance in
order to finish development of the rest of the system.  Company never
delivers the network cards. Customer doesn't ask for down payment back,
because he got what he really needed - the MAC numbers.  See how it
works?


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Re: MAC Address Chips
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They do now sell blocks of 4096 for US $550:
    http://standards.ieee.org/regauth/oui/pilot-ind.html

Not great pricing since blocks of 16777216 cost $1650.

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I agree with you even though I'm an IEEE member.

If I had an IEEE-assigned OUI, and wanted to sell off Ethernet address
space, I'd offer some lame product with an Ethernet port for sale for an
outrageous amount of money (say $5000), expecting to sell exactly zero
units.  But I'd offer a "replacement" address EEPROM containing a
guaranteed unique address dirt cheap.

Re: MAC Address Chips
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Did you check Rabbit Semiconductor?  I think they sell uniquely
serialized EEPROMS compatible with the Realtek 8019 ethernet
chip.


Re: MAC Address Chips
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Which IMHO does not mean that they could not be read out by a CPU and
used with other chips too.

Markus

Re: MAC Address Chips

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What's your point?  He didn't specify whether or not a CPU
would read the chip.  In any case, it would be fairly trivial
to bit-bang the MAC number out of the chip.  I've done it.



Re: MAC Address Chips
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Errr - yes, that was my point :)

Markus

Re: MAC Address Chips

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Sorry, my parser only caught half of that double-negative.




Re: MAC Address Chips
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The IEEE's position on this is unnecessarily against the "little guy",
but the path you're taking isn't reliable.

The IEEE assigns the first 24 bits (OUI) of the MAC address, with the
remaining 24 administered by the manufacturer.  There is no way to
randomly generate MAC addresses without the risk (albeit very low) of
colliding with either a functional address (group addresses) or another
vendor's OUI space.

The proper solution would be for IEEE to offer a low-cost option for
registering small blocks within a multi-vendor OUI (e.g., $25 for 10
specific MACs).  Some companies have tried to do this within their own
OUI, and the IEEE actively squashes their attempts.

An alternative is to buy cheap / defunct Ethernet products, destroy
them, and use their MAC, but then your device will appear to be from
another registered manufacturer (who might object).

And, the MAC is usually burned into an EPROM.  Why add a chip for the
MAC?

Re: MAC Address Chips
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There are "Individual Address Blocks" (IABs).  4096 addresses, for
about $550, last time I checked.

https://standards.ieee.org/regauth/oui/forms/IAB-form.shtml

Re: MAC Address Chips

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That's correct - I just registered one such block.

AFAIK, it's the least expensive way to get unique MAC addresses (besides
cannibalizing old NIC's).

Tauno Voipio
tauno voipio @ iki fi



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Unless you've got free labor, I can't imagine that
cannibalizing old NIC's would be cheap.

--
Grant Edwards                   grante             Yow!  ... If I had heart
                                  at               failure right now,
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Re: MAC Address Chips

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I meant jus stealing the addresses from them and then making sure that
nobody's able to use the originals anymore.

Tauno Voipio
tauno voipio @ iki fi




Re: MAC Address Chips

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I know -- but even that is going to involve quite a bit of
labor (espeically if the MAC aren't printed on the boards) when
compared with the US$0.13 per address you paid for your 4K
block.

--
Grant Edwards                   grante             Yow!  QUIET!! I'm being
                                  at               CREATIVE!! Is it GREAT
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Re: MAC Address Chips
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And depending on the NIC card maker, the MAC might not be unique.  A
number of them just cycled through their block.  Some cycled through
someone else's block.  A few used the same MAC for all their cards in a
production run.

For a hobbyist, re-using a MAC or two is no-biggy, but in a commercial
environment, better safe than sorry and cheaper too.

--
Ron Sharp.



Re: MAC Address Chips

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Well here in South Africa, the trade unions have negotiated a
minimum wage of approx 50 US cent per hour. In practice with
the problems in Zimbabwe, labour is available at a 10th of this
minimum wage. One will of course have to set up a system where
unskilled labour is suitable.

Regards
   Anton Erasmus


Re: MAC Address Chips
The only way to guarantee that you won't clash is to get them from the
source - ieee - sorry, that's life.

Andrew

Ted Wood wrote:

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