MAC Address

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Hello,


  I would like to know the MAC address of newly purchased LAN
controller chip. To be specific, SMSC LAN91C111. How do I get the MAC
address of this chip. I am using the chip in a standalone board have
some boot flash and is interfaced to 32 bit RISC processor. Can anybody
help me?

Thanks in Advance

Regards
Anil


Re: MAC Address
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I never used this particular chip, but usually the MAC is not on chip.
You have to program the chip to use the MAC you want to assign it.
Methods vary from using a small serial flash to using the host
processor storing it into some registers etc. The datasheet for the
SMSC part you refer to surely will give you the answer.

If your question is about a ready made board you purchased somewhere,
you could use a lan analyzer ( www.ethereal.com ) to sniff it of the
net. Provided the board uses DHCP or otherwise sends even a single
frame to the net you would see it.

HTH

Markus


Re: MAC Address

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You don't even need to go that far. Just ping it from a machine and look
at your ARP table. On a windoze box, use 'arp -a' after pinging it.

Regards,
Mark

Re: MAC Address
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Youre right, but if he fidles around with network controller chips,MAC
adresses and the like, chances are he will need a lan sniffer/analyzer
anyways :-). Besides, etheral is free and really a plug and play
experience.

Markus


Re: MAC Address

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It has whatever MAC address you purchase and assign to it. Look at
http://www.smsc.com/main/tools/lan9000/91c111ref.pdf , observe that
there's an EEPROM there. Your MAC lies within (or can be set from the
uC's firmware).


Re: MAC Address
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The 91C111 does not have a MAC memory on chip.

There are two ways to load the MAC on the chip:

  - SPI EEPROM connected to the chip, or
  - loading by software to the MAC registers directly.

You need to get a free MAC address. The addresses are
administered by IEEE. Look for OUI, it's the top part of
a MAC address.

For one-off projects, the simplest method by far
is to hi-jack the MAC address from a throw-away NIC.

HTH

--

Tauno Voipio
tauno voipio (at) iki fi


Re: MAC Address

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Or just make one up....



Re: MAC Address
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It's a disaster waiting to happen. IMHO, this
is not an option.

Besides, the invented address must conform to the
Ethernet addressing rules, so hi-jacking is by far
the easiest way, given the price of abandoned NICs.

--

Tauno Voipio
tauno voipio (at) iki fi



Re: MAC Address
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If you don't mind using one assigned to
jkmicro, send me an email and I'll give
you one of mine.


Re: MAC Address
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Ethernet reserves the least significant bit in the first byte for multicast
addresses (01-00-00-00-00-00).  There are no other Ethernet addressing
restrictions.

Given that MAC addresses are 48 bits long and only 1 bit is reserved for
multicast addresses, there are total of 2^47-1 possible unicast addresses.
Subnets normally consist of 253 or less computers, so there is an extremely
good probability that a random unicast address will not conflict with
already existant or future equipment.  Those are good enough odds that I
would bet my life on it for a one-off project.

If one really wanted to increase the odds of being unique, I'd suggest
downloading the list of registered OUI's [
http://standards.ieee.org/regauth/oui/oui.txt ] and look for a company that
has gone bankrupt and disappeared.  A non-existant company is not likely to
sue you if one of their (non-existant) users' equipment breaks because
you've used their addressing space.



Re: MAC Address
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You might also pick up a used ISA or PCI network card from a yard sale
or junk store and use that MAC.

Kelly

Re: MAC Address
: >>>For one-off projects, the simplest method by far
: >>>is to hi-jack the MAC address from a throw-away NIC.
: >>
: >>
: >> Or just make one up....
: >
: > It's a disaster waiting to happen. IMHO, this
: > is not an option.
: >
: > Besides, the invented address must conform to the
: > Ethernet addressing rules, so hi-jacking is by far
: > the easiest way, given the price of abandoned NICs.

: Ethernet reserves the least significant bit in the first byte for multicast
: addresses (01-00-00-00-00-00).  There are no other Ethernet addressing
: restrictions.

The second least sig bit of the first byte is also reserved for indicating
administratively set MAC addresses. All allocated mac ranges have that bit
set to 0. Those with long memories and networks running decnet
will remember the administratively set "AA........" mac addresses
decnet created.

If you invent a MAC address - set this bit.

Jim


: Given that MAC addresses are 48 bits long and only 1 bit is reserved for
: multicast addresses, there are total of 2^47-1 possible unicast addresses.
: Subnets normally consist of 253 or less computers, so there is an extremely
: good probability that a random unicast address will not conflict with
: already existant or future equipment.  Those are good enough odds that I
: would bet my life on it for a one-off project.

: If one really wanted to increase the odds of being unique, I'd suggest
: downloading the list of registered OUI's [
: http://standards.ieee.org/regauth/oui/oui.txt ] and look for a company that
: has gone bankrupt and disappeared.  A non-existant company is not likely to
: sue you if one of their (non-existant) users' equipment breaks because
: you've used their addressing space.



Re: MAC Address
On Wed, 21 Sep 2005 22:51:59 +0200, Tauno Voipio  

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why ? Nforce2 mobos have same MACs sometimes :)

--
taa

Re: MAC Address

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Recycling an address from an old card is fine.
Problems with making one up are highly improbable these days as MAC addresses
rarely have any
significance outside the immediate vicinity.

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