Re: New Plaintext QUIC-LB Design

Martin Duke <martin.h.duke@gmail.com> Mon, 11 January 2021 23:32 UTC

Return-Path: <martin.h.duke@gmail.com>
X-Original-To: quic@ietfa.amsl.com
Delivered-To: quic@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id BCEDF3A14FB for <quic@ietfa.amsl.com>; Mon, 11 Jan 2021 15:32:14 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.098
X-Spam-Level:
X-Spam-Status: No, score=-2.098 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.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 PAofCo1VcVyT for <quic@ietfa.amsl.com>; Mon, 11 Jan 2021 15:32:13 -0800 (PST)
Received: from mail-il1-x12d.google.com (mail-il1-x12d.google.com [IPv6:2607:f8b0:4864:20::12d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 72A753A1413 for <quic@ietf.org>; Mon, 11 Jan 2021 15:32:13 -0800 (PST)
Received: by mail-il1-x12d.google.com with SMTP id x15so1093933ilk.3 for <quic@ietf.org>; Mon, 11 Jan 2021 15:32:13 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=oMpoOJVI7POKSrvrQBswHtNXLNa/vrjOCSzxCpGBl7U=; b=SfUVOgSgYBI30N6d0AsSNEaYO5MjgNprg5dCkwL5Laa45oh9/FGaGODMC+KF5ifIYF uBldrmethoYeelwjag7mLr6JtPyS4C2xJ5XbE9yk7pNzauCTebdUiHjQ8YMjsri/ZjjR EdnT9wATyibdblH9o/Nar0obgttFsjLJd1lbxDGP98MlS+5toTwGrP1uwDJeVppbFMsr qgQGxqHZFbP3YxMe7g2+QlMPIh9iAEz9iiEJ7v3WyIeTDsuvhGhFcc3xiFHJK8Jjfh9M tL4MYS8VTlNt6Na6URGGLi7ORntmCGE48l3o2aoAgYATpIAr9UPt/asJtHsgjSao+Qwq ZbHg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=oMpoOJVI7POKSrvrQBswHtNXLNa/vrjOCSzxCpGBl7U=; b=MLknBj6DLBRLPF3/cCPpsamPvIfwtlPyBxsswGKckZkLtMfnxdprrBZ4tzttevKuqZ ek9DETJbVV/B8MKfsJShZGD12jNekf8VA3JZP6Zwg1rQes5EUYAUIEGLtTt2Anw2dL26 ZOeW+BbfqBGBoD6iXBQfJ50hqQ/Vmbo1Wk4FpRN1Qf0tPWdfj/Qtu1Tq3PCwyVcOCHnb IthA3foEgY7EZ/vMaIZaToVqNSlnnrcJtU1b4WqWuigZF7CTzrX5AoT/vNK33cC0vK/Q G6i/HKkKVbceSLoAeVrBHfkFlAa+iZVOWacnTs15Gmws4Ci6r9DI3KKoBRPHIkM2j68T O4ww==
X-Gm-Message-State: AOAM531XEtpJoXeRIeE1Ozvvvn2ZkMRDlb/IdYug2M01HUVFTf1fGW3a 3rEIsAVSBrH7XXiX4zUHrQLctLDIGAy3xAduRa8=
X-Google-Smtp-Source: ABdhPJxqsZg6I+RUr+Azw7pYRCz7/TpmP7u+qdDMRTqMwbNoilAnCj8NiYTVY3j5+Pog7OywYetPucT9Y/zUc8xyvlA=
X-Received: by 2002:a92:da0f:: with SMTP id z15mr1279477ilm.287.1610407932726; Mon, 11 Jan 2021 15:32:12 -0800 (PST)
MIME-Version: 1.0
References: <CAM4esxRRp5=-YvcPsCdsgB=8O=_RAXq05Ldma0smGsjy95T4=g@mail.gmail.com> <6B05568D-1905-4416-904C-2EEC25491920@gmail.com>
In-Reply-To: <6B05568D-1905-4416-904C-2EEC25491920@gmail.com>
From: Martin Duke <martin.h.duke@gmail.com>
Date: Mon, 11 Jan 2021 15:32:11 -0800
Message-ID: <CAM4esxSyn7uEiUsYvtiUbQ=4Qt-Bp+yLYBK+re+a+V3ea0BjcQ@mail.gmail.com>
Subject: Re: New Plaintext QUIC-LB Design
To: =?UTF-8?Q?Mikkel_Fahn=C3=B8e_J=C3=B8rgensen?= <mikkelfj@gmail.com>
Cc: IETF QUIC WG <quic@ietf.org>
Content-Type: multipart/alternative; boundary="000000000000c613fb05b8a8507c"
Archived-At: <https://mailarchive.ietf.org/arch/msg/quic/I3KFyE2JbKE74WMA4-hdnVbqDgM>
X-BeenThere: quic@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Main mailing list of the IETF QUIC working group <quic.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/quic>, <mailto:quic-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/quic/>
List-Post: <mailto:quic@ietf.org>
List-Help: <mailto:quic-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/quic>, <mailto:quic-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 11 Jan 2021 23:32:15 -0000

Hi Mikkel,

Answers inline

On Mon, Jan 11, 2021 at 3:19 PM Mikkel Fahnøe Jørgensen <mikkelfj@gmail.com>
wrote:

> I’m trying to read through the LB document that I haven’t looked at for
> quite a while. It isn’t very clear to me, I am sorry to say.
>
> I do not understand why the highest configuration value is chosen since
> this value would eventually wrap? Is there an implied wider config value
> where only the lower bits are visible, similar to packet numbers?
>

In general, client-generated CIDs might come in with config rotation bits
that don't correspond to an existing config. For the other algorithms, it's
randomly routed and after that the server-generated CID is used. But for
this algorithm, the server needs to extract a server ID somehow. If there's
one configuration, that's simple. If there's more than one, there has to be
deterministic behavior. The choice to use the highest is completely
arbitrary; I'm open to other suggestions that have better properties.


> Also, I do not understand how the server receives the assigned SID. Is the
> ODCID replaced in first packets, or are the packets unmodified, or is the
> SID prefixed the real packet?
>

No, any 8-byte CID will contain a server ID. So the client, in effect,
generates an SID and the load balancer decides which server will get it
(and then use that SID in the future)


> If the ODCID is modified, what about message authentication, also in
> future versions and with possible shared keys?
>

It is not modified, see above

Is the state table affected by the clients choice of ODCID (think abuse)?
>

Yes, if CIDs are chosen to maximize the number of different SIDs, that will
grow the table. IMO this isn't substantially different from randomly chosen
CIDs, which is of course normal behavior.