Re: Go Back to Single Packet Number Space

Martin Thomson <> Thu, 26 July 2018 01:42 UTC

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From: Martin Thomson <>
Date: Thu, 26 Jul 2018 11:41:48 +1000
Message-ID: <>
Subject: Re: Go Back to Single Packet Number Space
To: Nick Banks <>
Cc: QUIC WG <>
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The feedback I've heard is that the simplification is subjective.
Others have said that a single space would complicate their
implementation considerably more.  You might want to say more about

The loss of acknowledgements during the Initial phase has the
unfortunate effect of forcing implementations to rely on implicit
acknowledgment.  This doesn't seem like a problem now, but we're close
to the quantum computer cryptographic apocalypse (put that on a
sandwich board and yell it on street corners folks!) and this sort of
reduction in capability could serious impair our ability to ship a key
exchange that doesn't have problems.

Now, this latter thing is not an unfixable problem if you cared about
it, but it depends on what your real problem is.
On Thu, Jul 26, 2018 at 5:29 AM Nick Banks
<> wrote:
> Hello Folks,
> I have opened a GitHub Issue (#1579) and Pull Request (#1591) for this topic, but it seems progressed has stalled, so I figured I should take it to the list.
> While implementing draft-13, I came across a number of pain points related to using multiple packet number spaces. A lot of the issues result in duplicated state (and associated memory) for all the packet number spaces. But more importantly, the multiple packet number spaces bring in a lot more complexity of logic, compared to the previous single packet number space design. There is a lot more detail in the GitHub issue, and I’d ask that folks take a look at it (and the PR) and provide any feedback they might have. I feel that my Issue adequately describes the problem and my PR provides good (if not better, IMO) solutions to the problems that were fixed previously with multiple packet number spaces. I believe having a single packet number space will drastically simplify implementations in the end.
> Finally, as QUIC V1 (2?) is coming to a close (hopefully) I feel like we should resolve this issue soon. I don’t want this issue to slip out into the next version.
> Thanks,
> - Nick