Re: [quicwg/base-drafts] Use "Insert Count" rather than "Largest Reference" (#2111)

Mike Bishop <notifications@github.com> Mon, 07 January 2019 23:42 UTC

Return-Path: <noreply@github.com>
X-Original-To: quic-issues@ietfa.amsl.com
Delivered-To: quic-issues@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5EA58124408 for <quic-issues@ietfa.amsl.com>; Mon, 7 Jan 2019 15:42:13 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -8.065
X-Spam-Level:
X-Spam-Status: No, score=-8.065 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.065, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=github.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id W5a-4qJpVlrd for <quic-issues@ietfa.amsl.com>; Mon, 7 Jan 2019 15:42:10 -0800 (PST)
Received: from out-1.smtp.github.com (out-1.smtp.github.com [192.30.252.192]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 8D82112008A for <quic-issues@ietf.org>; Mon, 7 Jan 2019 15:42:10 -0800 (PST)
Date: Mon, 07 Jan 2019 15:42:09 -0800
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1546904529; bh=FfPZKifomlDEAU9/uhOoUa2sWJVS9ffhltL73itaYr8=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=2Orr85ugBStmmxFpATRw32SiZxPUOxTbwyniGBKeLG2cvhJfc17976EOB0Y28u9VR v3NkXFP7rVLbwXtTA4lGYS5++cLCQtUMjNymrHsc0HU4Wo7d0x220B4BtSgPSAa6Da /A7/pR6n1y23OMI6rRICCdLFdio29X9vEqXNpVOM=
From: Mike Bishop <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+0166e4ab948030c77c0d5c040a4ceed41357fb882a9a3fc292cf00000001184ba5d192a169ce17392ee3@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/2111/review/190039015@github.com>
In-Reply-To: <quicwg/base-drafts/pull/2111@github.com>
References: <quicwg/base-drafts/pull/2111@github.com>
Subject: Re: [quicwg/base-drafts] Use "Insert Count" rather than "Largest Reference" (#2111)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5c33e3d19474b_72a13fb3054d45c095813d"; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: MikeBishop
X-GitHub-Recipient: quic-issues
X-GitHub-Reason: subscribed
X-Auto-Response-Suppress: All
X-GitHub-Recipient-Address: quic-issues@ietf.org
Archived-At: <https://mailarchive.ietf.org/arch/msg/quic-issues/h0wu_kaM5xQ6LxP_HOTRAQWbZjU>
X-BeenThere: quic-issues@ietf.org
X-Mailman-Version: 2.1.29
List-Id: Notification list for GitHub issues related to the QUIC WG <quic-issues.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/quic-issues/>
List-Post: <mailto:quic-issues@ietf.org>
List-Help: <mailto:quic-issues-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 07 Jan 2019 23:42:13 -0000

MikeBishop approved this pull request.

In general, I think this is a good improvement.  You seem to switch from using "Base" to using "the Base" part-way through, so I'd pick one and switch the others.

> @@ -444,33 +452,40 @@ referenced by a given relative index will change while interpreting instructions
 on the encoder stream.
 
 ~~~~~ drawing
-    +---+---------------+-----------+
-    | n |      ...      |   d + 1   |  Absolute Index
-    + - +---------------+ - - - - - +
-    | 0 |      ...      | n - d - 1 |  Relative Index
-    +---+---------------+-----------+
-      ^                       |
-      |                       V
-Insertion Point         Dropping Point
+      +---+---------------+-----------+
+      | n |      ...      |     d     |  Absolute Index

If Absolute Index is zero-based, then the Absolute Index of the most recently inserted item would be n-1.

>  
-Header data is prefixed with two integers, `Largest Reference` and `Base Index`.
+Each header block is prefixed with two integers.  The Required Insert Count
+encoded as an integer with an 8-bit prefix after the encoding described in

**is** encoded, presumably.

>  ~~~
 
-TotalNumberOfInserts is the total number of inserts into the decoder's
-dynamic table.  This encoding limits the length of the prefix on
-long-lived connections.
+Where TotalNumberOfInserts is the total number of inserts into the decoder's

I know that the actual intent is to continue the previous sentence (...using the following algorithm, where....), but this reads as a dangling phrase.  If you want the "where," maybe move the whole thing above the algorithm?

>  
 A header block that does not reference the dynamic table can use any value for
-Base Index; setting both Largest Reference and Base Index to zero is the most
+Base; setting both Required Insert Count and Delta Base to zero is the most
 efficient encoding.

NYT but isn't it required to set a correct RIC?

> -Because frames from request streams can be delivered out of order with
-instructions on the encoder stream, relative indices are relative to the Base
-Index at the beginning of the header block (see {{header-prefix}}). The Base
-Index is an absolute index. When interpreting the rest of the frame, the entry
-identified by Base Index has a relative index of zero.  The relative indices of
-entries do not change while interpreting headers on a request or push stream.
+Unlike on the encoder stream, relative indices on push and request streams are
+relative to the Base at the beginning of the header block (see
+{{header-prefix}}). This ensures that references are stable even if the dynamic
+table is updated while decoding a header block.
+
+The Base is encoded as a value relative to the Required Insert Count. The Base
+identifies which dynamic table entries can be referenced using relative
+indexing, starting with 0 at the last entry added.
+
+Post-base references are used for entries inserted after base, starting at 0 for

"Base" is capitalized elsewhere

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/2111#pullrequestreview-190039015