Re: Packet number encryption negotiation

[Ian Swett <[e-mail]>]

Speaking as an individual, I would like to see this discussed more in the
QUIC WG, possibly in Yokohama.

Header Protection/PNE definitely helps with ossification, but when compared
with highly optimized and sometimes non-standard networking protocols, QUIC
without PNE is a huge improvement.  In a datacenter environment,
ossification is a concern, but it's rarely due to the wire image.

Ian

On Wed, Mar 8, 2023 at 8:02 AM Boris Pismenny <[e-mail]>
wrote:

>
>>
>>> What I want to add is that you should consider multipath QUIC when you
>>> design your hardware. It affects the AEAD nonce generation.
>>>
>>> Regular, unipath, QUIC sets the top 34 bits of the packet number to zero
>>> when generating the nonce. In the upcoming multipath extension, the top 32
>>> bits can be set to non-zero values.
>>>
>>> https://www.rfc-editor.org/rfc/rfc9001.html#name-aead-usage
>>>
>>> https://www.ietf.org/archive/id/draft-ietf-quic-multipath-03.html#name-packet-protection-for-quic
>>> -
>>>
>>
>> Thanks for the pointers, I've encountered multi-path QUIC on another
>> discussion about QUIC offload (
>> https://github.com/microsoft/quic-offloads/issues/9#issuecomment-1305823308
>> <https://protect2.fireeye.com/v1/url?k=31323334-501d5122-313273af-454445555731-88d69ea0099e1120&q=1&e=e27b5977-1b4e-4703-957b-3236511a2976&u=https%3A%2F%2Fgithub.com%2Fmicrosoft%2Fquic-offloads%2Fissues%2F9%23issuecomment-1305823308>).
>> IIUC, the main challenge with multipath will be to synchronize receive side
>> NIC offloads when two NICs are being used in parallel to carry the same
>> flow's packet number space.
>>
>>
>> There will only be separate packet number spaces for each path in the
>> upcoming version of the multipath draft. Then I guess you will not have the
>> problem you mention above. If you still would, why is this not a problem
>> with regular unipath QUIC?
>>
>>
> Indeed, this can also happen with unipath QUIC. In both cases, it is
> probably not the common case. But, if it does happen, it will make
> offloading more challenging.
>