FWIW:
Another caveat about using the header check to avoid the GUE header for
IPv4 and IPv6:
(A)- looking for only bit 01=1 would expect raw IP encapsulation for
versions 4-7 and 12-15, leaving out 8-11 (of which 10 and 11 are still
possible)
(B)- looking for either 01, 10, or 11 would allow all future IP
versions but prevent GUE from having versions of its own
Of these two, IMO, (A) is preferable, but I would strongly suggest:
(C)- match "01" means native IP, supporting only currently-used
versions 4 and 6
- define "10" and "11" as Reserved for future use
Joe
On 5/26/2016 11:52 AM, Tom Herbert wrote:
> 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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