Subject: Reference to IETF method of generating an EUI-64 out of a hardware address?

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Nov 2013 19:53:05 +0100

Hello 6man participants,

Is there a reference for the IETF method of generating an EUI-64 out of
a hardware address?

During today's 6man WG discussion I was assuming the method of forming
an EUI-64 out of a hardware address is specified by IEEE, not IETF.

But I heard a couple of comments around me that this may be wrong
assumption, i.e. the method of forming an EUI-64 out of a hardware
address _were_ specified by IETF.

I wonder whether there is a reference for this method?

Alex

---

From: Jen Linkova <[email-masked]>
Date: Mon, 4 Nov 2013 19:55:32 +0100

> I wonder whether there is a reference for this method?

http://tools.ietf.org/html/rfc4291#appendix-A

-- 
SY, Jen Linkova aka Furry

---

From: Eliot Lear <[email-masked]>
Date: Mon, 04 Nov 2013 10:56:55 -0800

See RFC 4291 Section 2.5.1.

Eliot
On 11/4/13 10:53 AM, Alexandru Petrescu wrote:
> --------------------------------------------------------------------
> IETF IPv6 working group mailing list
> [email-masked]
> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
> --------------------------------------------------------------------
>
>

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Nov 2013 20:01:14 +0100

> http://tools.ietf.org/html/rfc4291#appendix-A

That is an example, repeating the definition of the method.  The RFC 
says this:
>    [EUI64] defines a method to create an IEEE EUI-64 identifier from an
>    IEEE 48-bit MAC identifier.

[EUI64] has brackets, it's referring to IEEE:
>
>    [EUI64]   IEEE, "Guidelines for 64-bit Global Identifier (EUI-64)
>              Registration Authority",
>              http://standards.ieee.org/regauth/oui/tutorials/EUI64.html,
>              March 1997.

(worth mentiong as well a need for an errata for when it cites
  [EUI-64], note the dash, which does not exist)

Any other reference?

Alex

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Nov 2013 20:03:27 +0100

It says this:
>   Modified EUI-64 format-based interface identifiers may have universal
>    scope when derived from a universal token (e.g., IEEE 802 48-bit MAC
>    or IEEE EUI-64 identifiers [EUI64])

It is IEEE's [EUI64] reference who defines that the EUI-64 is derived 
from the MAC address, it's not this RFC.

Alex

---

From: Jen Linkova <[email-masked]>
Date: Mon, 4 Nov 2013 20:07:53 +0100

On Mon, Nov 4, 2013 at 8:01 PM, Alexandru Petrescu
<[email-masked]> wrote:
> That is an example, repeating the definition of the method.  The RFC says
> this:
>>

Sorry, I should have clarified.
1) AppendixA describe *how* to create Modified EUI-64 IID
2) Section 2.5.1 specifies that MEUI-64 is to be used:

For all unicast addresses, except those that start with the binary
   value 000, Interface IDs are required to be 64 bits long and to be
   constructed in Modified EUI-64 format.'

---

From: Brian E Carpenter <[email-masked]>
Date: Tue, 05 Nov 2013 08:10:29 +1300

> http://tools.ietf.org/html/rfc4291#appendix-A

And you might want to read
http://tools.ietf.org/html/draft-ietf-6man-ug-04
for the latest update to the text of 4291 (which does not
affect the actual EUI-64 to Modified EUI-64 conversion).

   Brian

---

From: Jen Linkova <[email-masked]>
Date: Mon, 4 Nov 2013 20:10:45 +0100

On Mon, Nov 4, 2013 at 8:03 PM, Alexandru Petrescu
<[email-masked]> wrote:
> It is IEEE's [EUI64] reference who defines that the EUI-64 is derived from
> the MAC address, it's not this RFC.

Modified EUI-64 is a format and it is defined in IEEE document.
RFC4291 says that particular format is to be used to create IID:

'For all unicast addresses, except those that start with the binary
   value 000, Interface IDs are required to be 64 bits long and to be
   constructed in Modified EUI-64 format.'

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Nov 2013 20:14:53 +0100

Le 04/11/2013 20:07, Jen Linkova a écrit :
>> That is an example, repeating the definition of the method.  The
>> RFC says this:
>>>
>>> [EUI64] defines a method to create an IEEE EUI-64 identifier from
>>> an IEEE 48-bit MAC identifier.
>>
>>
> Sorry, I should have clarified. 1) AppendixA describe *how* to create
> Modified EUI-64 IID

That is but an example, it is not authoritative.  It refers to IEEE:
>>> [EUI64] defines a method to create an IEEE EUI-64 identifier from
>>> an IEEE 48-bit MAC identifier.

IEEE can tomorrow deprecate that.  Or maybe they need a draft from IETF
to do so?

Alex

---

From: Brian E Carpenter <[email-masked]>
Date: Tue, 05 Nov 2013 08:16:24 +1300

Let's try this one more time:

IEEE specifies how an EUI-64 is generated from an EUI-48 (MAC address).

RFC 4291 specifies how a Modified EUI-64 is generated from an EUI-64.

draft-ietf-6man-ug-04 (with the AD now) makes it clear that
Modified EUI-64 is only one possible form of IID.

draft-gont-6man-deprecate-eui64-based-addresses proposes
to deprecate Modified EUI-64 usage.

Regards
   Brian

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Nov 2013 20:17:29 +0100

> Modified EUI-64 is a format and it is defined in IEEE document.

Yes and no.  It is a format.  But Modified EUI-64 is not defined by 
IEEE, but by IETF.  The 'Modified' word is IETF invention.  The EUI-64 
word is IEEE invention.

>     constructed in Modified EUI-64 format.'

Yes.  But the root cause of hw addresses finding themselves in an IPv6 
is at IEEE.  Were IEEE to deprecate the use of a hw address in an 
EUI-64, then there would be no problem.

Alex

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Nov 2013 20:20:35 +0100

Le 04/11/2013 20:16, Brian E Carpenter a écrit :
> draft-ietf-6man-ug-04 (with the AD now) makes it clear that Modified
> EUI-64 is only one possible form of IID.
>
> draft-gont-6man-deprecate-eui64-based-addresses proposes to deprecate
> Modified EUI-64 usage.

By doing so, I think draft-gont-6man-deprecate-eui64-based-addresses has
too many implications.

If all draft-gont-6man-deprecate-eui64-based-addresses wants to do is to
deprecate the use of a method which assumes hw addresses in an
EUI-64 then it would be sufficient for IEEE to deprecate that (IEEE to
deprecate the use of hw addresses in their definition of the EUI-64).

Alex

> Regards Brian
>>> Modified EUI-64 format-based interface identifiers may have
>>> universal scope when derived from a universal token (e.g., IEEE
>>> 802 48-bit MAC or IEEE EUI-64 identifiers [EUI64])
>>
>> It is IEEE's [EUI64] reference who defines that the EUI-64 is
>> derived from the MAC address, it's not this RFC.
>>
>> Alex
>>
>>>
>>> Eliot On 11/4/13 10:53 AM, Alexandru Petrescu wrote:
>>>> Hello 6man participants,
>>>>
>>>> Is there a reference for the IETF method of generating an
>>>> EUI-64 out of a hardware address?
>>>>
>>>> During today's 6man WG discussion I was assuming the method of
>>>> forming an EUI-64 out of a hardware address is specified by
>>>> IEEE, not IETF.
>>>>
>>>> But I heard a couple of comments around me that this may be
>>>> wrong assumption, i.e. the method of forming an EUI-64 out of a
>>>> hardware address _were_ specified by IETF.
>>>>
>>>> [email-masked] Administrative Requests:
>>>> https://www.ietf.org/mailman/listinfo/ipv6
>> IETF IPv6 working group mailing list [email-masked] Administrative
>> Requests: https://www.ietf.org/mailman/listinfo/ipv6

---

From: Dave Thaler <[email-masked]>
Date: Mon, 4 Nov 2013 19:21:22 +0000

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf Of
> Brian E Carpenter
> Sent: Monday, November 4, 2013 11:16 AM
> To: Alexandru Petrescu
> Cc: [email-masked]; Eliot Lear
> Subject: Re: Reference to IETF method of generating an EUI-64 out of a
> hardware address?
> 
> draft-ietf-6man-ug-04 (with the AD now) makes it clear that Modified EUI-64
> is only one possible form of IID.
> 

I think the intent is to propose to deprecate generating a Modified EUI64 from
an EUI-64, not to deprecate Modified EUI-64 usage (which has several other
ways to generate them).

-Dave
 
> >>> Is there a reference for the IETF method of generating an EUI-64 out
> >>> of a hardware address?
> >>>
> >>> forming an EUI-64 out of a hardware address is specified by IEEE, not
> IETF.
> >>>

---

From: Brian E Carpenter <[email-masked]>
Date: Tue, 05 Nov 2013 10:19:41 +1300

Dave,

> an EUI-64, not to deprecate Modified EUI-64 usage (which has several other

OK, I see your point, but it needs a bit more analysis. The -deprecate
draft currently says:

   NOTE: [RFC4291] defines the "Modified EUI-64 format" (which this
   document does not deprecate) for Interface identifiers.

However, draft-ietf-6man-ug-03 (which this WG has passed on to the AD)
updates RFC 4291 to say:

   "For all unicast addresses, except those that start with the binary
    value 000, Interface IDs are required to be 64 bits long. If derived
    from an IEEE MAC-layer address, they must be constructed in Modified
    EUI-64 format."

That removes the untrue implication of 4291 that all IIDs are in
Modified EUI-64 format, and elsewhere the draft clarifies that the u and
g bits are meaningless in IIDs. Therefore, I would submit that RFC 4291
as updated by draft-ietf-6man-ug-03 means that the *only* IIDs that are
in any real sense "in Modified EUI-64 format" are those actually derived
from an EUI-64 address.

I don't think the current text in the -deprecate draft reflects
the change made by draft-ietf-6man-ug-03.

  Brian

---

From: Fernando Gont <[email-masked]>
Date: Mon, 04 Nov 2013 12:26:10 -0800

> Modified EUI-64 is a format and it is defined in IEEE document.

That's incorrect. IEEE specifies EUI-64. IETF specifies Modified EUI-64
identifiers (based on IEEE's EUI-64).

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: [email-masked]
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492

---

From: Fernando Gont <[email-masked]>
Date: Mon, 04 Nov 2013 12:27:45 -0800

On 11/04/2013 11:17 AM, Alexandru Petrescu wrote:
>>>> universal
> is at IEEE.  

That's incorrect. The IEEE has no say on how we generate *IPv6* IIDs.

Thanks,

---

From: Jen Linkova <[email-masked]>
Date: Mon, 4 Nov 2013 23:15:02 +0100

> identifiers (based on IEEE's EUI-64).

oops, sorry, thanks for pointing this out. s/Modified EUI-64/EUI-64/ indeed.

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Nov 2013 23:54:28 +0100

> That's incorrect. The IEEE has no say on how we generate *IPv6* IIDs.

I think I agree.

We generate IIDs by relying on Modified EUI-64 mostly, which itself 
relies on EUI-64.

The ppp relies exclusively on IIDs which are not EUI-64.  Some ppp 
implementations use the hw address of the other interface to generate an 
IID.  This behaviour could be deprecated at IETF.

Alex

---

From: Fernando Gont <[email-masked]>
Date: Mon, 04 Nov 2013 14:17:34 -0800

Hi, Brian,

> the change made by draft-ietf-6man-ug-03.

Good point. I'll work with you and the other co-authors to improve the
draft on this issue.

Thanks,