[ntpwg] Pending NTP WG Last Call on Autokey

[David L. Mills]

Danny,

No sell. There are numeous examples of prior art in the use of a 16-bit 
length field in IP and UDP. I do not think it clean at all to poach on 
the length field. In any case, it doesn't really make much difference. 
What you see is what you get unless you have a specific proposal for a 
competitive protocol. Right now I don't hear anything.

Dave

Danny Mayer wrote:

> Dave,
>
>
> You misunderstand me. I'm proposing that autokey complies as well. 
> conformance bit set to 1 indicates that you are conforming to the 
> protocol while conformance bit 0 (which it would have to be in order 
> to be the top bit of the length field) would mean the old format and 
> would be non-compliant with the autokey protocol and the NTPv4 spec. 
> The old autokey usage of the field type would go away.
>
>
> I'll send you the layout at little layer.
>
>
> Danny
>
>
> David L. Mills wrote:
>
>> Dannt,
>>
>>
>> Each of us has proposed stealing bits from the length field or the 
>> code fields. I find stealing from the length field inelegant, while 
>> you might find theft of code bits crude. Your proposal cleaves 
>> Autokey from any other and does not necessarily provide for multiple 
>> others. I prefer my proposal.
>>
>>
>> Dave
>>
>>
>> Danny Mayer wrote:
>>
>>
>>> Dave,
>>>
>>>
>>> My proposal that I sent out quite a long time ago was to steal a bit 
>>> from the length field and set it to 1 for the updated protocol so 
>>> that the particulars of the autokey protocol remains private inside 
>>> the header extension itself and keeps it outside the field type. 
>>> That way the servers (including those of NIST, USNO, etc.) can 
>>> continue to work with both versions (the old and the new). The old 
>>> clients (servers) will continue to work. Taking away one bit from 
>>> the length field reduces the maximum extension length from 65535 to 
>>> 32767 which I don't think we will ever need or can use.
>>>
>>>
>>> It's this lack of privacy of this data that causes interoperability 
>>> problems between Autokey and Microsoft's MS-SNTP protocols, 
>>> otherwise this issue would never have arisen.
>>>
>>>
>>> Danny
>>>
>>>
>>> David L. Mills wrote:
>>>
>>>
>>>> Danny,
>>>>
>>>>
>>>> I hear no proposals about extension fields other than my last 
>>>> proposed rewrite of that section. There really is no wiggle room 
>>>> other than deprecating Autokey in its present form and reformatting 
>>>> the headers. I am not opposed to that in principle, but others, 
>>>> specificlly USNO, have not been heard from.
>>>>
>>>>
>>>> Dave
>>>>
>>>>
>>
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>>
>