About GUID

[anand_gore]

I want to know somthing about the GUID....
That generated ID is really unique...
If i am not on inet or if i dont have ethernet card..the is it such that GUID assigned by me to the interface is useless??Or i cannt use it if i am on net.??
Will it face problem like Y2k after some years as the ethernet cards nos will be over ....this may be a foolish question i guess but sorry for that...

Can Anybody also tell me that how the IEEE is taking care about the unique numbers given to the Ethernet cards..
Thanks a lot.
Anand

[chiuyan]

If you do not have a network card, various other elements are used to synthesize a machine identifier number to use in its place. Even in this case, the chance that your machine has the same identifier as some other machine are extremely small.

I am not sure who is responsible for assigning network card address, or how it is handled--so I do not know if we will ever run out of numbers.

[Valerie Bradley]

The network card identifiers (a.k.a. MAC IDs) are a combination of two elements:

First 3 bytes = Vendor ID. Each vendor has one or more IDs to uniquely identify it. For example, one of Intel's Vendor IDs is 00A0C9.

Last 3 bytes = Unique Card ID. The vendor then assigns to each card a unique identifier which no other card will have. For example, 12FE8B.

The combination of these two components creates a unique ID which one and only one network card can have. In this example, the complete MAC address would be 00A0C912FE8B.

I believe that once all the unique card IDs are used (i.e. all IDs in the range of 00A0C9000000 - 00A0C9FFFFFF), an additional Vendor ID is given to the vendor and they start the process all over again.

I hope this helps!

=================================================
Valerie L. Bradley
Software Engineer
Intel Corporation

* All opinions expressed are mine and not those of my employer.

[Robert Rolls]

Who assigns the vendor ID's ?

[Valerie Bradley]

I don't know who assigns the IDs, probably the IEEE. I think that you actually BUY the ID from them.

For everything you wanted (and didn't want) to know about Ethernet addressing, I recommend you look over the IEEE 802.3 specification.


=================================================
Valerie L. Bradley
Software Engineer
Intel Corporation

* All opinions expressed are mine and not those of my employer.