On Wed, Apr 29, 2015 at 10:20 AM, Templin, Fred L
<[email protected]> wrote:
> Hi Tom,
>
>> -----Original Message-----
>> From: Tom Herbert [mailto:[email protected]]
>> Sent: Wednesday, April 29, 2015 10:13 AM
>> To: Templin, Fred L
>> Cc: Lucy yong; [email protected]; [email protected]
>> Subject: Re: [Int-area] Why combine IP-in-UDP with GUE?
>>
>> On Wed, Apr 29, 2015 at 9:28 AM, Templin, Fred L
>> <[email protected]> wrote:
>> > Hi Tom,
>> >
>> >> -----Original Message-----
>> >> From: Tom Herbert [mailto:[email protected]]
>> >> Sent: Wednesday, April 29, 2015 9:00 AM
>> >> To: Templin, Fred L
>> >> Cc: Lucy yong; [email protected]; [email protected]
>> >> Subject: Re: [Int-area] Why combine IP-in-UDP with GUE?
>> >>
>> >> On Wed, Apr 29, 2015 at 7:50 AM, Templin, Fred L
>> >> <[email protected]> wrote:
>> >> > Hi Lucy,
>> >> >
>> >> >> -----Original Message-----
>> >> >> From: Lucy yong [mailto:[email protected]]
>> >> >> Sent: Wednesday, April 29, 2015 7:48 AM
>> >> >> To: Templin, Fred L; [email protected]; [email protected]
>> >> >> Subject: RE: [Int-area] Why combine IP-in-UDP with GUE?
>> >> >>
>> >> >>
>> >> >> Getting back to our earlier discussion, IP-in-UDP and GUE are 
>> >> >> currently two half-solutions. Put them together and you get a
>> whole
>> >> >> solution.
>> >> >> Keep them apart, and someone else is going to have to write a whole 
>> >> >> solution sometime down the line from now.
>> >> >> [Lucy] GUE can support IP payload. Don't know why you state that they 
>> >> >> are two half-solutions. Is the compression a mandatory
>> >> >> requirement here? I think that IP-in-UDP proposal as a compression 
>> >> >> version is better that use of first nibble. However we need
>> >> clarify
>> >> >> what limitation and constraint the compression solution has.
>> >> >
>> >> > GUE is missing header compression, and IP-in-UDP is missing tunnel
>> >> > fragmentation. That is what I mean when I say that if combined you
>> >> > get a whole solution.
>> >> >
>> >> Adding this header compression just adds a whole bunch of complexity
>> >
>> > The only additional requirement is to check the first nibble of the
>> > UDP-encapsulated payload.
>> >
>> >> to the protocol to save a grand total of four bytes for what is likely
>> >> a very narrow use case. This is not applicable when GUE is used for
>> >> network virtualization, we are encapsulating something other than IP,
>> >> we need OAM, or using any other feature of GUE. In my deployment, I
>> >> don't have any use case for that since minimally I will be using
>> >> remote checksum offload option because that does give a material
>> >> performance advantage.
>> >
>> > What you have just done is spelled out specific use cases that
>> > require special-purpose solutions - that is not "generic".
>> >
>> >> The premise of GUE is simple, it has a simple header that encapsulates
>> >> any IP protocol expressed by IP protocol number and allows optional
>> >> extensions and control packets-- let's keep it simple! If saving those
>> >> four bytes is really important in some deployment and GUE is still
>> >> needed in certain case, then just use GUE and IP-in-UDP in tandem.
>> >
>> > That would require two different UDP port numbers as opposed to
>> > checking the first nibble, which there was some earlier discussion
>> > about. If you want to call something "generic", then why not make it
>> > truly generic?
>> >
>>
>> It already is generic. Encapsulation of IPv4 and IPv6 is already
>> implemented and deployed. Including this optimization does not make
>> the protocol more generic.
>
> If it is deployed before the document is published as an RFC, then
> the deployed base would have to be updated to match the eventual
> RFC anyway.
>
>> Anyway, if you want to proceed with this please provide a specific
>> proposal on how do to it.
>
> Change the GUE header to treat the first nibble as a next header
> selector. 4 means IPv4, 6 means IPv6 and X means GUE.
>
By "specific" I mean down to the bit what *exactly* will this new
proposed GUE header format be.

> Thanks - Fred
> [email protected]
>
>> Tom
>>
>> > Thanks - Fred
>> > [email protected]
>> >
>> >> Tom
>> >>
>> >> > Thanks - Fred
>> >> > [email protected]
>> >> >
>> >> >> Lucy
>> >> >>
>> >> >> Thanks - Fred
>> >> >> [email protected]
>> >> >>
>> >> >> > However, if GUE payload is
>> >> >> > IP, it is OK to inspect the first nibble of the payload to determine 
>> >> >> > IPv4 or IPv6 because this aligns with IP protocol.
>> >> >> >
>> >> >> > Thanks,
>> >> >> > Lucy
>> >> >> >
>> >> >> > - Stewart
>> >> >> >
>> >> >> >
>> >> >> >
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