Can you make the change so we can try to advance the document to last call?

Dino

> On Apr 27, 2016, at 1:23 PM, Anton Smirnov <[email protected]> wrote:
> 
> we will consider this input for the next doc revision.
> 
> Anton
> 
> 
>> On 04/27/2016 07:06 PM, Dino Farinacci wrote:
>> 
>>>   Hi Dino,
>>>   since XEID prefix is not seen anywhere on the wire these words should not 
>>> be viewed as normative; more like guidance for implementers. For DDT 
>>> specification itself it is not important if IID is 24-bit, 32-bit or any 
>>> other bit length. DDT relies on other control plane specifications (notably 
>>> LCAF draft) to specify how IID looks like and how it is propagated in 
>>> control messages.
>> 
>> If that is the case, why is the length included in the text then? I disagree 
>> though, the length is critically important because it conveys the maximum 
>> number of VPNs, per mapping system, that can be supported.
>> 
>>>   LCAF draft currently depicts 32-bit space to store IID on the figure but 
>>> then goes on saying:
>>> 
>>>>   Instance ID:  the low-order 24-bits that can go into a LISP data
>>>>      header when the I-bit is set.  See [RFC6830] for details.
>> 
>> Right, because that is the only way to fit 32-bits into 24. ;-)
>> 
>>>   So IMO the ambiguity comes from the LCAF document. draft-ietf-lisp-lcaf 
>>> should be more specific on IID length. Furthermore, if LCAF draft 
>>> explicitly defined IID to be 32-bits then it should discuss what to do with 
>>> excess bits in case of LISP encapsulation.
>> 
>> No, this is not true. And you might not have the history of DDT. But we put 
>> 32-bits in the DDT document and then had the encoding in the LCAF document 
>> reflect that.
>> 
>>>   If DDT draft progresses before LCAF draft then it is more correct to be 
>>> compatible with existing RFCs in saying that IID is a 24-bit value. DDT doc 
>>> does not look like a proper place to redefine IID length from 24-bit to 
>>> 32-bits.
>> 
>> The LCAF draft just ended last call and is going to IESG.
>> 
>>>   If you strongly disagree with above then to unblock DDT spec from LCAF 
>>> ambiguity we may remove explicit mention of IID bit length from DDT spec 
>>> and put something like "IID as defined by the LCAF draft”.
>> 
>> You can’t remove it. You have to make it 32-bits otherwise you created an 
>> inconsistency that is (1) not needed and (2) for no good reason.
>> 
>> I suggest you leave that text alone and keep it at 32-bits.
>> 
>> Dino
>> 
>>> 
>>> Anton
>>> 
>>> 
>>>> On 04/25/2016 09:49 PM, Dino Farinacci wrote:
>>>> Authors, this change:
>>>> 
>>>> 
>>>> Is actually incorrect (change change is from 32 to 24). We have 32-bit
>>>> Instance-ID encodings in the LCAF Instance ID Type and want to support
>>>> that length in the control-plane EVEN THOUGH the data-plane can only
>>>> hold 24-bits.
>>>> 
>>>> Meaning, if you use different mapping systems, you can actually reuse
>>>> instance-IDs. This reuse was part of our initial intention.
>>>> 
>>>> Dino
>> 

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