Re: [Int-area] Call for adoption of draft-xu-intarea-ip-in-udp-03

[Joe Touch <[e-mail]>]

On 5/26/2016 11:22 AM, Tom Herbert wrote:
> On Thu, May 26, 2016 at 10:56 AM, Joe Touch <[e-mail]> wrote:
>>
>> On 5/26/2016 10:52 AM, Tom Herbert wrote:
>>> On Thu, May 26, 2016 at 10:41 AM, Joe Touch <[e-mail]> 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.

Joe