Subject: [quicwg/base-drafts] 65d2ac: More detail regarding dropping of ACK Ranges

From: Martin Thomson <[email-masked]>
Date: Tue, 14 Apr 2020 18:34:19 -0700

Branch: refs/heads/keep-acknowledged
  Home:   https://github.com/quicwg/base-drafts
  Commit: 65d2acbe3055ab996a07fd9a9c56626e66052844
      https://github.com/quicwg/base-drafts/commit/65d2acbe3055ab996a07fd9a9c56626e66052844
  Author: Martin Thomson <[email-masked]>
  Date:   2020-04-15 (Wed, 15 Apr 2020)

  Changed paths:
    M draft-ietf-quic-transport.md

  Log Message:
  -----------
  More detail regarding dropping of ACK Ranges

This explains what needs to be kept and why.  Specifically, you need to
keep ranges unless you have other means of ensuring that you don't
accept packets from those ranges again.  You also need to keep the
largest acknowledged so that you can get a packet number from subsequent
packets.

This also recommends that ACK frames include the largest acknowledged
always.  That is primarily to ensure that ECN works properly, and even
there, you only disable ECN if you get some weird reordering, so it's
probably not a big deal if you don't follow this recommendation.

Closes #3541.
Closes #3537.