On Thu, May 26, 2016 at 11:35 AM, Templin, Fred L
<[email protected]> wrote:
> Hi Joe and Tom,
>
>> -----Original Message-----
>> From: Joe Touch [mailto:[email protected]]
>> Sent: Thursday, May 26, 2016 11:26 AM
>> To: Tom Herbert <[email protected]>
>> Cc: Templin, Fred L <[email protected]>; [email protected]
>> Subject: Re: [Int-area] Call for adoption of draft-xu-intarea-ip-in-udp-03
>>
>>
>>
>> On 5/26/2016 11:22 AM, Tom Herbert wrote:
>> > On Thu, May 26, 2016 at 10:56 AM, Joe Touch <[email protected]> wrote:
>> >>
>> >> On 5/26/2016 10:52 AM, Tom Herbert wrote:
>> >>> On Thu, May 26, 2016 at 10:41 AM, Joe Touch <[email protected]> wrote:
>> >>>> Here's the problem:
>> >>>>
>> >>>> The first 4 bits are either part of the GUE header or IPv4 or IPv6.
>> >>>>
>> >>>> In the diagrams in draft-ietf-nvo3-gue and RFC791 they're indicated in 
>> >>>> the
>> >>>> following bit order: 0,1,2,3
>> >>>>
>> >>>> In GUE, these are 0,0,x,x
>> >>>>
>> >>>> In IPv4, these are 0,0,1,0
>> >>>>
>> >>>> In IPv6, these are 0,1,1,0
>> >>>>
>> >>> IPv4 is 0,1,0,0.
>> >> Not LSB to MSB, which is how both GUE and RFC791 define the header:
>> >>
>> > >From RFC791:
>> >
>> > "Whenever an octet represents a numeric quantity the left most bit in
>> > the diagram is the high order or most significant bit.  That is, the
>> > bit
>> > labeled 0 is the most significant bit."
>> Arrgh.
>>
>> Yup. OK, so the reason this would work is only because we no longer use
>> IP versions 0..3.
>>
>> Got it.
>
> I for one like it, and I am using it in my AERO implementation. As Joe points 
> out
> however it does not account for fragmentation, identification etc. But, as 
> long
> as you use it in a carefully controlled environment it should be OK.
>
> Can we have this added back to the GUE spec?
>
Since it technically defines a new version of GUE and other than the
two bit version number there is nothing else in common with GUEv0
format, I would say this should be a new spec (I need to go back and
see if I wrote it up this in a draft).

Fred, do you have any objective data showing the benefits? I think we
need something tangible to justify complexity (i.e. burning 25% of the
GUE version number space  ;-) )

Thanks,
Tom

> Thanks - Fred
>
>>
>> Joe
>

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