Re: [Masque] WGLC for "Requirements for a MASQUE Protocol to Proxy IP Traffic"

[Spencer Dawkins at IETF <[e-mail]>]

Thank you, David

Best,

Spencer

On Fri, Jun 11, 2021, 20:59 David Schinazi <[e-mail]> wrote:

> Thanks Chris B,
>
> I've created a PR that incorporates your MTU text, and also should answer
> Magnus' question about trust:
>
> https://github.com/ietf-wg-masque/draft-ietf-masque-ip-proxy-reqs/pull/33/files
>
> Thanks,
> David
>
> On Fri, Jun 11, 2021 at 8:07 AM Spencer Dawkins at IETF <
> [e-mail]> wrote:
>
>> Chris,
>>
>> On Fri, Jun 11, 2021 at 9:20 AM Chris Box <[e-mail]>
>> wrote:
>>
>>> The endpoints in this document are the endpoints of the tunnel.
>>>> The goal of the MTU requirement is to mention that these endpoints
>>>> can share what they view as the max MTU. That would be the MTU
>>>> of the tunnel itself. You're right that connections that go through the
>>>> tunnel but don't terminate on the tunnel endpoints would need to
>>>> also take into account MTUs for the IP hops on either side of the
>>>> tunnel. One way to accomplish that is PMTUD between the ends of
>>>> that connection.
>>>>
>>>
>>> That makes sense. In that case, can we clarify the wording? Something
>>> like this perhaps?
>>>
>>>    The protocol will allow tunnel endpoints to inform each other of the Maximum
>>>    Transmission Unit (MTU) they are willing to forward.  This will allow
>>>    avoiding some IP fragmentation, especially as IPv6 does not allow IP
>>>    fragmentation by nodes along the path. In cases where the tunnel endpoint
>>>
>>>    is not the same as the communication endpoint, tunnel endpoints are
>>>
>>>    expected to apply the guidance on UDP tunnels in [BCP145].
>>>
>>>
>>> Chris
>>>
>>
>> Your question was a good one. I think your proposal is also helpful,
>> especially with the pointer to  BCP 145.
>>
>> Thank you for that.
>>
>> Best,
>>
>> Spencer
>>
>