Where do I get a MAC address from?

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I started playing with Zigbit900 modules when I found that they are not coming with a pre-loaded MAC address.
How can I make sure to chose one that hasn't already been choosen by my neighbour by coincidence?

Cheers, Bay

Last Edited: Fri. Oct 16, 2015 - 02:27 PM
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You need to buy a range of addresses from http://standards.ieee.org/develop/regauth/oui/public.html.

But most people just use UID chips, which is technically wrong, but much cheaper for some projects.

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some zigibt module come with Sn number which is 64-bit , what is that for?

Thanks

Regards

DJ

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None of them come with SN, so I don't know what you are talking about.

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Well there is sticker on my modules.

DJ

Thanks

Regards

DJ

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Can you show couple of the numbers from them?

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Once I get back I will take a Picture?

Thanks

Regards

DJ

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Sure. I just want to see if they look like real MAC address or not. I guess for a module Atmel is allowed to give them out.

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I have not got the chance to try the modules as I am waiting for some PCB's, but it would be good to see if they are programed in the EEPROM

Thanks

Regards

DJ

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[Not very often I frequent the wireless forum, but this got me curious]

Quote:

But most people just use UID chips

I'm with you on why this is wrong, but give that: What is the advantage of using a UID chip as compared to just generating a GUID in software.

How about locating a bunch of very old, dated and technically passé network cards, write down their MAC addresses and them smash them under the hammer? :D (Think: 3-Com 3C509 or Western Digital WD-8003 ISA cards)

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Say if you had 100s over PCB's how would you give each a unique ID, without recompiling many times. Is there any feature in the Studio that lets you program a serial to EEPROM location?

Thanks

Regards

DJ

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Quote:

Is there any feature in the Studio that lets you program a serial to EEPROM location?

There is a feature to program the contents of a file to the EEPROM. You will have to generate that file, though - i.e. no serial-number-generator as such in Studio.

And, as has been hinted to above by Alex: MAC addresses are not something you can generate on your own. Properly handled they are never re-used. The authority that sees to this is the IEEE. If you need MAC addresses you buy a series from IEEE. MAC addresses are 48 bits (6 bytes).

Since GUIDs where mentioned: A GUID is a 128-bit unique identifier. One way of accomplishing this (IIRC) is to use a MAC address available in the generating machine and combine this with a timestamp and a random number. (Check details on this in the article linked to - I haven't been into GUIDs since 1990-something..)

If you want to protect yourself from other disturbing your net then creating MAC addresses from wisely thought out cut-outs of locally generated GUIDs might do.

If you want to make absolutely sure that you do not disturb anyone else then I can think of no other scheme than to buy MAC addresses from IEEE.

(Or "nick" (pun intended) the MAC addresses off old 802.something devices and then destroy those devices beyond further use or repair.)

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Please find the image attached in regards to serial number.

Attachment(s): 

Thanks

Regards

DJ

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141896? Methinks it needs a "warning, larks vomit"

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JohanEkdahl wrote:
I'm with you on why this is wrong, but give that: What is the advantage of using a UID chip as compared to just generating a GUID in software.
You are guaranteed that all your devices will be unique if you buy UID chips from one manufacturer. When you generate them mistakes will happen, you'll lose your database, etc.

This SN does not look like a valid IEEE address, but I think they might be used instead of UID chip if you don't mind programing each device with its S/N.

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JohanEkdahl wrote:
If you need MAC addresses you buy a series from IEEE. MAC addresses are 48 bits (6 bytes).
I thought it was 8 bytes.. Are you talking about Ethernet MAC addresses?

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First bytes are manufacturer ID, and you get 48 bits to use as you wish.

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Quote:

I thought it was 8 bytes.. Are you talking about Ethernet MAC addresses?

Yup. Told you above that I'm not here at Wireless often, and I just displayed my ignorance assuming we where talking MAC-48...

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"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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Quote:
Yup. Told you above that I'm not here at Wireless often, and I just displayed my ignorance assuming we where talking MAC-48...
Most of what you said applies here too though..

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> I guess for a module Atmel is allowed to give them out.

I wouldn't see why it were not allowed to do so. If you buy an
Ethernet module from someone, it comes with a MAC address from that
vendor's OUI range, and even if you insert it into your own final
device, it still propagates that vendor's OUI across the Ethernet. If
you buy a PC from Dell or HP, you wouldn't expect them to ship with a
Dell or HP MAC address on their onboard Ethernet.

So why shouldn't that be possible with an IEEE 802.15.4 module? After
all, Atmel has got the OUI assignment anyway (so no additional cost is
involved), which leaves 40 bit of per-module ID address space. 2^40
is approximately 10^12, I doubt this amount would "wear out" really
soon now ...

Jörg Wunsch

Please don't send me PMs, use email if you want to approach me personally.

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MAC address? If the device is used on your LAN with a router between it and the Internet, simply use a MAC address with bit 1 of the MSB set. Like 02 xx xx xx ...

Per the IEEE, that's a self-administered MAC address for use on private LANs or LANs that use NAT or some such.

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Steve, I slipped into classical Ethernet MAC addresses (6 bytes) too. It turns out that this is about

Apparently (I often learns something new here at 'freaks) this is about 8-byte MACs used in (.e.g.?) ZigBee networks.

As of January 15, 2018, Site fix-up work has begun! Now do your part and report any bugs or deficiencies here

No guarantees, but if we don't report problems they won't get much of  a chance to be fixed! Details/discussions at link given just above.

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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The new terms are extended universal identifiers, EUI-48 and EUI-64. Yes, 802.15.4 uses EUI-64 but there is a specified mapping from MAC-48 and EUI-48 (inserts 0xffff or 0xfffe) that allows legacy mac addresses.

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That makes me thinking: Is no-one out there doing something like a "MAC-pool" where MAC addresses are bought in in bulk (as they usually are) and on-sold in smaller units? Most companies don't really need millions of them but maybe a few thousands ...

Cheers, Bay

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I'm fairly sure it is illegal, because your company's prefix will be in the database.

It is definitely illegal with USB VIDs.

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[off-topic]

alexru wrote:
I'm fairly sure it is illegal, because your company's prefix will be in the database.

Might be. But as mentoned above, if I buy a PC, the MAC address of the ETH might be assigned to a network chip company. And the WIFI MAC might be assigned to another company which does WIFI modules.
Ideally, Atmel would have already put one in. Which is not very practical if we as users want to have that much control over the hardware and need to be able to erase the EEPROM if needed.
Would be great if all the ATmegas would have a MAC already set in an OTP ... just dreaming!

alexru wrote:
It is definitely illegal with USB VIDs.

As far as I remember, USB VIDs are only 16bit and, as the name says, Vendor IDs. Even though, if I sell a product and use, for instance, one of the standard FTDI chips to convert USB to UART, the computer will see the FTDI VID.
Haven't checked but I would assume that a MeshBean will report on an FTDI VID (or similar) on it's UART-via-USB.

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I understand, and I want to have a unique ID in every chip too, not even MAC, just unique. I think some (all?) Atmel boards that naturally come with Ethernet port have a MAC address at least printed on the label. But I'm not sure if reselling a bunch of them is legal.

As far as USB goes, there was some fuss about changing VID on Atmel Meshbeans for legal reasons. Nobody cared about this on Meshnetics' ones though.

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Quote:
Would be great if all the ATmegas would have a MAC already set in an OTP ... just dreaming!

The AVR USB variants come with a unique 10 byte serial number in the signature row. Not a true MAC address though, but for the purposes for USB it's good enough.

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Some ARMs have UID as well. So it is available here and there, but not something one can really rely on.

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The deRFmega128 modules have a MAC address stored in the internal 4K EEPROM for deRFsam3 and deRFsam7 based modules the MAC address is stored in NRVRAM. Beside the MAC address a CRC is stored to verify that the address is not corrupted.

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> It is definitely illegal with USB VIDs.

Well, the USB IF *declared* that to be illegal, and threatened anyone
of those few resellers with legal actions. As the resellers were
usually just small shops (typically one-man shows), they did not want
to risk anything, and (more or less) volunteerily stopped reselling
PIDs out of their range. Consequently, no court ever decided whether
that practice was really illegal or not. It's not all that unlikely
a court would have decided another way ...

The short-sightness here is they assigned just a 16-bit address space
for the VID in the first place - by a time, when the exhaustion of
32-bit IPv4 addresses has been known already for about a decade. Now
they have to defend that nonsense, and to try keeping only "valuable
vendors" in the right of obtaining a VID ... thus they don't intervent
if someone like Microchip or FTDI effectively resell their VID (by
allowing you to use one of their PIDs along with their hardware), while
declaring the same thing for "standalone" resellers illegal.

Jörg Wunsch

Please don't send me PMs, use email if you want to approach me personally.

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th33lf wrote:
JohanEkdahl wrote:
If you need MAC addresses you buy a series from IEEE. MAC addresses are 48 bits (6 bytes).
I thought it was 8 bytes.. Are you talking about Ethernet MAC addresses?
yes, OUIs are 64 bit. MAC addresses of 802.15.4 are 64 bits. I understand that MAC addresses (6 or 8 byte) are one purpose of OUIs.