Re: [STDS-802-Privacy] Locally-administered bit and OUI registration
Hello,
On 9/20/16, 7:26 AM, "Roger B. Marks" <r.b.marks@xxxxxxxx> wrote:
>Célestin,
>
>You should have a look at this IEEE RA tutorial:
> http://standards.ieee.org/develop/regauth/tut/eui48.pdf
>
>It explains that the IEEE RA assigns OUIs with the local (U/L) bit set to 0 and that it assigns CIDs with the local bit set to 1. If you flip the U/L bit in an OUI, you don't have an OUI; what you have is an invalid CID or someone else's CID.
Not if you're doing MAC randomization (which is what the question was about). There is no
prohibition on using locally-administered addresses on a network and there is no notion of
"someone else's CID" when doing MAC randomization.
To answer Célestin's first question: "are there any texts specifying whether OUI with LA bit
set to 1 have to be registered to be used?"
No, there is no requirement to register anything if you're doing MAC randomization. If you
want to manage locally-administered addresses and have them assigned to devices using a
CID then you have to get a CID, if you don't care about managing locally-administered
addresses and just want devices to choose them randomly then you're free to do anything
you want (and you get to deal with any conflicts that may arise).
>The P802c draft (D1.2), currently under development, says:
>
>"Changing the X bit of an RA-assigned OUI is not authorized by the IEEE RA, does not result in a valid CID, may invalidly duplicate a valid CID assignment, and shall not be used as the basis of an ELI." In P802c, the ELI ("extended local identifier") is used as a local MAC address.
This snippet is the answer to Célestin's second question: "are there any texts stating that OUI
with LA bit set to 1 is automatically reserved for the vendor when the correspond OUI with LA
bit set to 0 is registered?"
Not only are there no texts stating that, there are (proposed) texts stating the opposite. You
don't get a CID by setting the X-bit of your RA-assigned OUI.
It comes down to how you want to administer your network. If you want to manage address
assignment you need to get a CID and do it that way. If you don't want to manage address
assignment and just let devices chose addresses randomly you don't need to do anything.
Dan.
>Roger
>
>
>Roger B. Marks <r.b.marks@xxxxxxxx>
>EthAirNet Associates
>
>> On 2016Sep 20, at 7:46:43AM, Matte Célestin <celestin.matte@xxxxxxxxxxxx> wrote:
>>
>> Hi all,
>>
>> I'm currently working on studying the adoption of MAC address
>> randomization over time.
>> As you know, vendors have to register a OUI (also called MA-L) at IEEE
>> before using it to generate MAC addresses for its devices [1].
>> Some (but not all) devices set the locally administered (LA) bit of the
>> OUI part of their MAC address to 1 when using a random MAC address.
>> I'm wondering if the newly-created OUI has to be registered as well to
>> be used; I can't seem to find any text stating if this has to be done or
>> not, or if this is done implicitly.
>> In the whole oui.txt file (listing all registered OUIs), a little bit
>> more than a dozen OUI withs the LA bit set to one are listed, and do not
>> correspond to devices actually seen in the wild doing MAC address
>> randomization.
>>
>> So, my questions are:
>> - are there any texts specifying whether OUI with LA bit set to 1 have
>> to be registered to be used?
>> - are there any texts stating that OUI with LA bit set to 1 is
>> automatically reserved for the vendor when the correspond OUI with LA
>> bit set to 0 is registered?
>>
>> [1] :
>> https://regauth.standards.ieee.org/standards-ra-web/pub/view.html#registries
>>
>> Regards,
>> --
>> Célestin Matte