Re: Spin bit decision

[Marten Seemann <[e-mail]>]

> One of my concerns is unintentional mis-use of the signal, and if it
can't be detected reliably in a mixed environment, that means SHOULD is
unwise and argues for either not including it or making it a MUST.

The problem is, even if we decide to make it a MUST, a middlebox still
needs to distinguish between QUIC traffic and other UDP traffic. We're not
exposing any unambiguous signal to the path that a particular flow actually
is QUIC traffic, so middlebox vendors will have to come up with some kind
of heuristic to identify QUIC.
My fear is that if all implementations actually implement the spin bit, and
middleboxes learn to rely on that signal (and enforce compliance), we might
do great harm to other UDP based protocols (current and future) which
happen to use the same code points that middleboxes came to rely on.

Coming back to Alexandre's question, I think here is little an experiment
could do to assuage that fear. This is just another symptom of exposing
this signal in the wrong OSI layer.


On Tue, Oct 2, 2018 at 10:18 AM Ian Swett <ianswett=
[e-mail]> wrote:

> One piece of information related to the above discussion is whether
> detecting who is and is not spinning is easy and reliable.
>
> One of my concerns is unintentional mis-use of the signal, and if it can't
> be detected reliably in a mixed environment, that means SHOULD is unwise
> and argues for either not including it or making it a MUST.
>
> On Tue, Oct 2, 2018 at 12:51 PM Mike Bishop <[e-mail]> wrote:
>
>> I don’t think it’s a grim view, I think it’s a pragmatic view.  Our role
>> is to specify the things which are fundamental to the protocol and have to
>> happen for peers to interoperate.  Mis-using normative language for other
>> things is an abuse of the process -- that's kind of the point of RFC 6919.
>>
>>
>>
>> RFC 2119 says:
>>
>> In particular, [normative language] MUST only be used where it is
>> actually required for interoperation or to limit behavior which has
>> potential for causing harm (e.g., limiting retransmisssions)  For example,
>> they must not be used to try to impose a particular method on implementors
>> where the method is not required for interoperability.
>>
>>
>>
>> Given that the spin bit is not “actually required for interoperation,”
>> but is the very definition of “try to impose a particular method on
>> implementors,” I’d say that RFC 2119 imperatives are unwarranted.
>>
>>
>>
>> -----Original Message-----
>> From: QUIC <[e-mail]> On Behalf Of
>> [e-mail]
>> Sent: Tuesday, October 2, 2018 8:05 AM
>> To: Lars Eggert <[e-mail]>
>> Cc: IETF QUIC WG <[e-mail]>
>> Subject: Re: Spin bit decision
>>
>>
>>
>> On 10/02/18 16:00, Lars Eggert wrote:
>>
>> >
>>
>> > The point I can't seem to be getting across is that irrespective of
>>
>> > what the WG decides to require, there is no penalty for individual
>>
>> > stacks at deployment time (or after) to do whatever they wish, since
>>
>> > the spin bit by design has no impact on protocol operation and interop.
>>
>>
>>
>> It is getting across, but it is a very grim view of the standardization
>> process itself. Are there many examples of MUST in RFCs that turned out to
>> be ignored by implementations just because they were not part of the core
>> semantics and hence not enforced by other peers ?
>>
>>
>>
>>
>>
>>
>> _________________________________________________________________________________________________________________________
>>
>>
>>
>> Ce message et ses pieces jointes peuvent contenir des informations
>> confidentielles ou privilegiees et ne doivent donc pas etre diffuses,
>> exploites ou copies sans autorisation. Si vous avez recu ce message par
>> erreur, veuillez le signaler a l'expediteur et le detruire ainsi que les
>> pieces jointes. Les messages electroniques etant susceptibles d'alteration,
>> Orange decline toute responsabilite si ce message a ete altere, deforme ou
>> falsifie. Merci.
>>
>>
>>
>> This message and its attachments may contain confidential or privileged
>> information that may be protected by law; they should not be distributed,
>> used or copied without authorisation.
>>
>> If you have received this email in error, please notify the sender and
>> delete this message and its attachments.
>>
>> As emails may be altered, Orange is not liable for messages that have
>> been modified, changed or falsified.
>>
>> Thank you.
>>
>>
>>
>