Re: IID length text

[Behcet Sarikaya <[e-mail]>]

On Mon, Jan 16, 2017 at 4:09 PM, Fernando Gont <[e-mail]> wrote:
> On 01/16/2017 06:22 PM, Behcet Sarikaya wrote:
>> On Mon, Jan 16, 2017 at 2:46 PM, Fernando Gont <[e-mail]> wrote:
>>> On 01/16/2017 05:42 PM, Behcet Sarikaya wrote:
>>>> On Mon, Jan 16, 2017 at 2:27 PM, Alexandre Petrescu
>>>> <[e-mail]> wrote:
>>>>> Le 14/01/2017 à 20:49, Brian E Carpenter a écrit :
>>>>>>
>>>>>> A modest suggestion:
>>>>>>
>>>>>> OLD
>>>>>>    For all unicast addresses, except those that start with the binary
>>>>>>    value 000, Interface IDs are required to be 64 bits long.  Background
>>>>>>    on the 64 bit boundary in IPv6 addresses can be found in [RFC7421].
>>>>>>
>>>>>> NEW
>>>>>>    IPv6 routing is based on prefixes of any valid length up to 128
>>>>>> [BCP198].
>>>>>>    For example, [RFC6164] standardises 127 bit  prefixes on point-to-point
>>>>>>    links. However, consistent use of Stateless Address Autoconfiguration
>>>>>>    (SLAAC)[RFC4862] requires that all interfaces on a link use the same
>>>>>> length
>>>>>>    of Interface ID. In practice, this means that to guarantee
>>>>>> interoperability
>>>>>>    of SLAAC, a fixed length of Interface ID is necessary. For all
>>>>>> currently
>>>>>>    allocated unicast addresses, except those that start with the binary
>>>>>>    value 000, that length is 64 bits. Note that this value is an arbitrary
>>>>>>    choice and might be changed for some future allocation of unicast
>>>>>> address
>>>>>>    space. Background on the 64 bit boundary in IPv6 addresses can be found
>>>>>>    in [RFC7421].
>>>>>
>>>>>
>>>>> I agree with the change suggestion.  The new text and references are enough
>>>>> motivation to clarify that that 64bit limit is an arbitrary choice and might
>>>>> change in the future.
>>>>>
>>>>
>>>> 3GPP assigns 64 bit prefixes to each UE.
>>>> Extended Unique Identifiers defined are EUI-48 and EUI-64.
>>>
>>> What does a layer-2 EUI have to do with a layer-3 address?
>>
>> I don't know, you tell me :-)
>
> Answer: Nothing. The fact that we've been embedding layer-2 "addresses"
> into layer-3 addresses should not be taken as a reason for the two of
> them of having to do anything with each other. So, yes, the 64-bit IID
> length is, in reality, arbitrary. They could have been e.g. 32-bits or
> 48-bits (yes, multiples or 64 or 32 tend to be nicer)
>

I don't think you know much about MAC addresses and its history.

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