Re: [quicwg/base-drafts] Padding outside QUIC packet (#3333)

Will Hawkins <notifications@github.com> Mon, 13 January 2020 05:41 UTC

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Date: Sun, 12 Jan 2020 21:41:34 -0800
From: Will Hawkins <notifications@github.com>
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Subject: Re: [quicwg/base-drafts] Padding outside QUIC packet (#3333)
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> https://quicwg.org/base-drafts/draft-ietf-quic-transport.html#section-14 only says that padding is done by PADDING frame. https://quicwg.org/base-drafts/draft-ietf-quic-transport.html#section-14
> 
> But it looks like it is a common practice to add 0 or garbage outside QUIC packet to fill remaining UDP packet payload to expand packet size.

Just FYI: Adding 0-value bytes outside QUIC packets to fill remaining UDP datagram is the way that neqo currently performs padding. Of course, as @ekr says, it only does this when it is possible (there are only QUIC packets with long headers in the datagram).

> If it is a good practice (and/or recommended), I think draft should say something about it.
> It might slightly simplify the implementation.
> Padding in this way has different properties than PADDING frame; for example, it does not contribute to in-flight bytes.

  I, too, think it would be nice to have some clarification like this in the standard.  

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