Re: 64bit MAC addresses and SLAAC

On Wed, Jun 17, 2020 at 1:24 PM Etienne-Victor Depasquale <edepa@ieee.org>
wrote:

> Bob,
>
> In the case of resource-constrained nodes, such as wireless sensor
> networks (WSNs),
> the use of algorithms to generate addresses consumes energy.
>
> In my lectures to date (I'm an academic),
> I've emphasized that SLAAC in IPv6
> requires less energy than automatic address configuration in IPv4.
>
> RFC7217's method of address generation seems to load WSNs unnecessarily,
> unless the identity of a sensor is somehow considered important.
>
> RFC 8064 also says:

   In some network technologies and adaptation layers, the use of an IID
   based on a link-layer address may offer some advantages.  For
   example, [RFC6282 <https://tools.ietf.org/html/rfc6282>] allows for
the compression of IPv6 datagrams over
   IEEE 802.15.4-based networks [RFC4944
<https://tools.ietf.org/html/rfc4944>] when the IID is based on the
   underlying link-layer address.

Maintenance of IPv6 sensor networks may trump privacy concerns.  At the
very least, we
might broach the subject of stable randomized 64-bit link-layer identifiers
with IEEE (I am
unaware if any discussions on this topic have occurred).

Kerry

Etienne
>
> On Wed, Jun 17, 2020 at 6:37 PM Bob Hinden <bob.hinden@gmail.com> wrote:
>
>> Alexandre,
>>
>> > On Jun 17, 2020, at 4:39 AM, Alexandre Petrescu <
>> alexandre.petrescu@gmail.com> wrote:
>> >
>> > Le 15/06/2020 à 23:01, Bob Hinden a écrit :
>> >> Alexandre,
>> >>> On Jun 15, 2020, at 1:23 PM, Alexandre Petrescu <
>> alexandre.petrescu@gmail.com> wrote:
>> >>> Hi,
>> >>> Before the sanitary situation I was studying an issue at ISO.
>> >>> The issue is about 64bit MAC addresses and SLAAC.
>> >>> SLAAC needs a 48bit MAC addresses in order to work, and it can not
>> work with a 64bit MAC address; (but yes, it can with 64bit IIDs).
>> >> SLACC does not specify the length of the Interface ID, it does not
>> require require 48-bit MAC addresses, and the reason for Modified EUI-64
>> Format Interface Identifiers in RFC4291 was to support 64bit EUI-64
>> Identifiers.   We have since moved away from using MAC addresses as
>> Interface IDs.  See RFC 8064.
>> >
>> > Bob,
>> >
>> > RFC8064 says "this document [...] recommends against embedding stable
>> > link-layer addresses in IPv6 Interface Identifiers”.
>>
>> The actual text is:
>>
>>    By default, nodes SHOULD NOT employ IPv6 address generation schemes
>>    that embed a stable link-layer address in the IID.
>>
>> It is more than a recommendation.
>>
>> >
>> > But a 64bit MAC address could be a random number as well, not
>> > necessarily stable.  Windows randomizes some of its MAC addresses..
>>
>> RFC7721 discusses this, along with what Windows does.
>>
>> >
>> > That aside, I am not sure how much RFC8064 is clear about the length of
>> > an IID (it refers to RFC7217 '_could_ any len'), neither am I sure how
>> > much is it implemented (linux and freebsd implement random IIDs but of
>> > fixed length).
>>
>> The length of an Interface ID is not defined in RFC8063.  That is a
>> bigger topic, the current specification is RFC4291 as updated by RFC5952,
>> RFC6052, RFC7136, RFC7346, RFC7371, and RFC8064.
>>
>> Bob
>>
>>
>> >
>> > Alex
>>
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>
>
> --
> Ing. Etienne-Victor Depasquale
> Assistant Lecturer
> Department of Communications & Computer Engineering
> Faculty of Information & Communication Technology
> University of Malta
> Web. https://www.um.edu.mt/profile/etiennedepasquale
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