From dschinazi.ietf@gmail.com Thu Apr 18 07:57:28 2024 Return-Path: X-Original-To: babel@ietfa.amsl.com Delivered-To: babel@ietfa.amsl.com Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 4F90AC14F6AC for ; Thu, 18 Apr 2024 07:57:28 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -2.097 X-Spam-Level: X-Spam-Status: No, score=-2.097 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, GB_SUMOF=5, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_HI=-5, RCVD_IN_ZEN_BLOCKED_OPENDNS=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 ([50.223.129.194]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 11ecOfVb9tzJ for ; Thu, 18 Apr 2024 07:57:23 -0700 (PDT) Received: from mail-ej1-x630.google.com (mail-ej1-x630.google.com [IPv6:2a00:1450:4864:20::630]) (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 CEC39C14F68E for ; Thu, 18 Apr 2024 07:57:23 -0700 (PDT) Received: by mail-ej1-x630.google.com with SMTP id a640c23a62f3a-a524ecaf215so108367366b.2 for ; Thu, 18 Apr 2024 07:57:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1713452242; x=1714057042; darn=ietf.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=yjTJfS8IsDPrBoHgCpRCIh1y81MmnWtOxYvFM793Qvg=; b=Y/xZboWFrNGcxqn5UeywC5NCCQHpF6jcXWXqVc2/U7gbQazeZoVs2SLGEZddMBAkzX ODRcNYUBqGg7v3IUwiO1rqjaE/lYXEM36aGwNflQtv6HH1o6kQTYQio0RtKPyR3S9pBp pG8Xl2H64xl3wjmp6ynXka+zoodE1BL4iIDj2OZnU664tZpqJ79mOhsiKPu6L8GoHd6J Xn5HKcVHeuDJRS4qViaIqoUzKC/H3iDnL7uP/sxxc9OojjlVj7zhvEJkPTe42qDj622d RdENiuHBqva+0kBxDy0AUG1VnGztMr8xOfdRfVOG1CCHuzOUOdqonSAkotxFEXerdR1l mW6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1713452242; x=1714057042; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=yjTJfS8IsDPrBoHgCpRCIh1y81MmnWtOxYvFM793Qvg=; b=NayhHf+GOwedPOrPvMulcgsRZ288WCJ5x/tg9mJGvPOcB+LWh6NkJto2KT0fHBblpG k3pqmSeHb6YgroQ5kSrVRZK/YA0bCx8XG3yLbPzm8r28sY/vuLhU2eIU8GuABz1ojKqt eif1NT8Be+duvUJnA17+WkIpgEDN7VYie4imrryilAJD3kHvXx4eibTpm6YoMY8hbrv1 x19U1K6LtxtFyav0i4BCn7SpPOonhSQeyLZcOixBLLgmBPGIWwozLLJqBt2DE/R7qJN3 7ZWN9cqNSTTUhX7Lk9mmUFf3KVIAaoIAAbYQ1jn3PBSU4XtukwNwIcHnGHDXERvuDPsg eM4w== X-Forwarded-Encrypted: i=1; AJvYcCWHzRuBZ7dd+/yStZCLUh832Cuqxstk02NEzbuJC1qVqIRrfoHegOgtt5CCFx4zI+tbquHQQNvglwJU4464Mw== X-Gm-Message-State: AOJu0YyqamoFTx2D7/tdKReyVwAW+luPZQQjfTnfgPnu9gvY+gAJxNEx W64SQ+zIYCokBzND1ZXZ0sJb9CNpUHIdlxdsl6idBeEQiOCxoREr+qby8FF2MgPzNApuzQUEwmz DKFORQaKJHUnq2V3l9iW69YJBzjs= X-Google-Smtp-Source: AGHT+IFoFW/dMjN5Az5OZb45lOvogxite6Hhvq3JJn8HUaZ5j0exiK6KjhXg6i2O85b6gGRAJugLlWr+49bVky4VGrs= X-Received: by 2002:a17:906:4704:b0:a52:54be:de23 with SMTP id y4-20020a170906470400b00a5254bede23mr1909658ejq.15.1713452241640; Thu, 18 Apr 2024 07:57:21 -0700 (PDT) MIME-Version: 1.0 References: <171328574275.28898.9111599332162642753@ietfa.amsl.com> <87v84h5k56.wl-jch@irif.fr> <87r0f5urqv.fsf@toke.dk> <87sezki0w2.wl-jch@irif.fr> <87y19bu70m.fsf@toke.dk> <87bk67ixr9.wl-jch@irif.fr> <87plunu5nb.fsf@toke.dk> <87a5lritwi.wl-jch@irif.fr> <87o7a6n3yg.wl-jch@irif.fr> <87le5an37f.wl-jch@irif.fr> In-Reply-To: <87le5an37f.wl-jch@irif.fr> From: David Schinazi Date: Thu, 18 Apr 2024 07:57:10 -0700 Message-ID: To: Juliusz Chroboczek Cc: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , babel@ietf.org, Pascal Thubert Content-Type: multipart/alternative; boundary="00000000000033e8c70616603028" Archived-At: Subject: Re: [babel] New Version Notification for draft-ietf-babel-rtt-extension-06.txt X-BeenThere: babel@ietf.org X-Mailman-Version: 2.1.39 Precedence: list List-Id: "A list for discussion of the Babel Routing Protocol." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Apr 2024 14:57:28 -0000 --00000000000033e8c70616603028 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Thanks Juliusz, this helps. First, to set the stage - I'll be happy with any option you select, this is just to assuage my curiosity. In terms of the differences between the various options: 1) ease/possibility of implementation This one is important, but - if we assume that all implementations don't need to match - then we can just say "SHOULD implement as low in the stack as you can" and everyone can do that on whatever platform they are 2) symmetry As you point out, since RTT is the sum of both one-way delays, it will always be symmetric :-) 3) scheduling jitter I would assume that it's best to not count scheduling jitter since that'll most likely pollute the measurements and not impact the actual flow of packets along this route I guess the bit I'm not sure about is the assumption that I mentioned above: the fact that implementations don't need to match. Is there any reason why we'd want them to match? David On Thu, Apr 18, 2024 at 7:41=E2=80=AFAM Juliusz Chroboczek wr= ote: > > Properties of =CE=B4: > > > - it's not symmetric (it only includes local queueing delay); > > > Properties of =CE=B7: > > > - it's not symmetric; > > Sorry, that's not correct. All three measures are symmetric. Mills' > algorithm is just too brilliant for my small brain to encompass. > > -- Juliusz > --00000000000033e8c70616603028 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Thanks Juliusz, this helps.

First, to s= et the stage - I'll be happy with any option you select, this is just t= o assuage=C2=A0my curiosity.

In terms of the diffe= rences between the various options:

1) ease/possib= ility of implementation
This one is important, but - if we assume= that all implementations don't need to match - then we can just say &q= uot;SHOULD implement as low in the stack as you can" and everyone can = do that on whatever platform they are

2) symmetry<= /div>
As you point out, since RTT is the sum of both one-way delays, it= will always be symmetric :-)

3) scheduling jitter=
I would assume that it's best to not count scheduling jitter= since that'll most likely pollute=C2=A0the measurements and not impact= the actual flow of packets along this route

I gue= ss the bit I'm not sure about is the assumption that I mentioned above:= the fact that implementations don't need to match. Is there any reason= why we'd want them to match?

David
=

On Thu, Apr 18, 2024 at 7:41=E2=80=AFAM Juliusz Chroboczek <jch@irif.fr> wrote:
> Properties of =CE=B4:

>=C2=A0 =C2=A0- it's not symmetric (it only includes local queueing = delay);

> Properties of =CE=B7:

>=C2=A0 =C2=A0- it's not symmetric;

Sorry, that's not correct.=C2=A0 All three measures are symmetric.=C2= =A0 Mills'
algorithm is just too brilliant for my small brain to encompass.

-- Juliusz
--00000000000033e8c70616603028--