[Ppm] Seeking input on DAP PR #297

Christopher Patton <cpatton@cloudflare.com> Thu, 11 August 2022 20:44 UTC

Return-Path: <cpatton@cloudflare.com>
X-Original-To: ppm@ietfa.amsl.com
Delivered-To: ppm@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 0B87CC14F74A for <ppm@ietfa.amsl.com>; Thu, 11 Aug 2022 13:44:37 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.106
X-Spam-Level:
X-Spam-Status: No, score=-2.106 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01, URIBL_BLOCKED=0.001, URIBL_DBL_BLOCKED_OPENDNS=0.001, URIBL_ZEN_BLOCKED_OPENDNS=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=cloudflare.com
Received: from mail.ietf.org ([50.223.129.194]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SrGOWgf2Nh6w for <ppm@ietfa.amsl.com>; Thu, 11 Aug 2022 13:44:32 -0700 (PDT)
Received: from mail-ed1-x532.google.com (mail-ed1-x532.google.com [IPv6:2a00:1450:4864:20::532]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id B6364C14CF0B for <ppm@ietf.org>; Thu, 11 Aug 2022 13:44:32 -0700 (PDT)
Received: by mail-ed1-x532.google.com with SMTP id x21so24413263edd.3 for <ppm@ietf.org>; Thu, 11 Aug 2022 13:44:32 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=to:subject:message-id:date:from:mime-version:from:to:cc; bh=JISH0NeJr0gcwQsXFTS2AOOprus/icjd9tksi+AplZ8=; b=YgC8wp+pK2DJ0nr/AYmSGVEmeJMQREuNUjVxSUfmAtiFv+OJhre8ICVNgi6ZSpaXlt hIT5U9cTkaz40SheKJUzF9rHmM+waFoUaVkP6O7MDc8cLNO81F7xF3pr/jbvRBjtRzwl U+eRZuJSyaCoalBzarwO+LJDCA3JawpYaUdwU=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc; bh=JISH0NeJr0gcwQsXFTS2AOOprus/icjd9tksi+AplZ8=; b=UBXsKWBh1h62nrysjW9tDWZxaYc3XuAaT6JzUVo7jMZ9Vn+YOP/GOX32PGtttodxxv 0uRpEPRCwSL7tIbOuBrrq0eNFLEh3pgKkmSnYixSkNxZmbESs/YeTDQIL47jfILDNkek 2px1PZYkGIDDdbIDFfazmJkMvUgILmZuQK8cZKjwxASPw1yfLwwfPIaPKtka83rrvCGq ms+IDe5g9T22ZYpnqJmYjsx3al+h8jlDUzN9WovodEHo3N0N3d3QH8tS4WljsIZiBlSR FDAsVtul4S5KUCPXYwzLJJgQIZetCtC72RiazQAN3pBWc/frIFUYS9UmPdFq+bXeZ6sK cOdQ==
X-Gm-Message-State: ACgBeo3kzXRXNSrFkGX4pMg7MjcaZHm386mtr3m092OYQ6WUxJmj6oL1 mzwjxI4qcRx5On5bKZsNyIDoLUdko5ar+SLztWBdR8wfQdcOdA==
X-Google-Smtp-Source: AA6agR7CP2JwkUofsmi7dr/hfNfoHGxWZuCf8oClbWYkehdTpu7F9vRVGoqokaDUmVT8GPnS8uyexGn/ZNULSpIxFRo=
X-Received: by 2002:a05:6402:329b:b0:43d:bd4b:2f08 with SMTP id f27-20020a056402329b00b0043dbd4b2f08mr792573eda.244.1660250671019; Thu, 11 Aug 2022 13:44:31 -0700 (PDT)
MIME-Version: 1.0
From: Christopher Patton <cpatton@cloudflare.com>
Date: Thu, 11 Aug 2022 13:44:20 -0700
Message-ID: <CAG2Zi22BUdB+PhjWVneBSDb-c8-MnrpiYk5zV8PF4-mo6k7hqA@mail.gmail.com>
To: ppm <ppm@ietf.org>
Content-Type: multipart/alternative; boundary="0000000000007c6b6205e5fd3b61"
Archived-At: <https://mailarchive.ietf.org/arch/msg/ppm/u2SyuVwAevwa_03LGwp6msinSJo>
Subject: [Ppm] Seeking input on DAP PR #297
X-BeenThere: ppm@ietf.org
X-Mailman-Version: 2.1.39
Precedence: list
List-Id: Privacy Preserving Measurement technologies <ppm.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ppm>, <mailto:ppm-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ppm/>
List-Post: <mailto:ppm@ietf.org>
List-Help: <mailto:ppm-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ppm>, <mailto:ppm-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 11 Aug 2022 20:44:37 -0000

Hi all,

The following PR adds support for the "fixed-size batch" use case discussed
at IETF 114:
https://github.com/ietf-wg-ppm/draft-ietf-ppm-dap/pull/297

It's in pretty good shape, but there is one outstanding question we'd like
to tease out before merging. At a very high level, it would be useful if
the protocol could be spelled in a way that makes the Helper completely
agnostic to the query type. In particular, its behavior should be the same
regardless of the query sent from Collector to the Leader.

Consider the following properties of DAP-01:

    (1.) a report can belong to exactly one batch
    (2.) batches are disjoint
    (3.) a query determines a unique batch

Together these properties ensure the Client knows exactly which batch its
report is included in (assuming at least one Aggregator is honest). This is
because of the timestamp included in its report and the fact that batches
are defined by non-overlapping time intervals.

If we drop the requirement for (3.) then we guarantee only that a Client's
report is included in at most one batch. In particular it has no assurance
of which batch it is included in.

I guess a good question to start with is: How important is (3.)? Can we
achieve it in a way that makes the Helper oblivious to query types?

Happy aggregating,
Chris P.