Re: [Ntp] Is one refid enough

Watson Ladd <watsonbladd@gmail.com> Thu, 05 September 2019 15:45 UTC

Return-Path: <watsonbladd@gmail.com>
X-Original-To: ntp@ietfa.amsl.com
Delivered-To: ntp@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 7561F120105 for <ntp@ietfa.amsl.com>; Thu, 5 Sep 2019 08:45:16 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.997
X-Spam-Level:
X-Spam-Status: No, score=-1.997 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=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 TGgX90WmLpKl for <ntp@ietfa.amsl.com>; Thu, 5 Sep 2019 08:45:07 -0700 (PDT)
Received: from mail-lj1-x231.google.com (mail-lj1-x231.google.com [IPv6:2a00:1450:4864:20::231]) (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 B71771200A1 for <ntp@ietf.org>; Thu, 5 Sep 2019 08:45:06 -0700 (PDT)
Received: by mail-lj1-x231.google.com with SMTP id u14so2980797ljj.11 for <ntp@ietf.org>; Thu, 05 Sep 2019 08:45:06 -0700 (PDT)
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=i9CJnWzxeEZLzVwHz6zWcMOKap8wf8KSm+gi9z6o9UU=; b=EgfUwPWa9cfk4h5f5zrUeBFEcK5pP/+64sVB2bAQx6Qywkqi+ueaI5DB8zoOQ9Oahf qtLFM5YQ+FBrJhtbtjn9vGpYgMzU7GKJm2dbJKNqcgNfaGRmvlriNguyXQYMPPcGzpQG IX+yBTiswmeLfBK0e/5fbhk34Y5kID6a8DYnTp5brodDC174+U2O6eGQ+CmaWm+qRDCK GDUNXri0q1SqhF93+DcYBilnj9LHZVL1r2kOev6Dgl2eWxafGjvCYw7UXOhTsY0sFSRD Kq+eGNeGfp6Xbsit8paPDVg74lQ2DVxGDnnA0FHLe9ERUMPC6yNNwoUTW/3Ed1WMiayy 4WpA==
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=i9CJnWzxeEZLzVwHz6zWcMOKap8wf8KSm+gi9z6o9UU=; b=ZHM1m5eL2Izd/kFGk1/fVY/OZ2O1pZSK3xtBap/aC7uQH9Yz9GnKY/4YVEgZh3M4pI Um37YS5555owHjiB9TNkmxVcBF5yIpFr6pfufv9cJcel2mUKC/Hzxqg2ValX7bn4SHGR csekOBe5NFjGlZBGHaXx7RKx1XTW6Ggtny/eiFwBzIERfFzkFc7DANrNiJivDwm1kWS2 9a2UxoRNntyEMb/KKlPL6YKgsRxAPX3PTyCcC9Efm+BcqaOYg7yhCLDhiXyCUME9ATaw 1X6uABuda2NpOkwq8OV3UV5M9QzM0vN5Ti0KOJiE0YAYAKH4P7d0t8U+OfsXbAo4W0CN UU7A==
X-Gm-Message-State: APjAAAUpBFJNYe2/pM9F0l+/8S+2erxZVMspndUP1uAAyQ4/F5fJtkEw bqgowQVlHvsB33MRE9oLlF+WI0mLFF7QqJj9x4M=
X-Google-Smtp-Source: APXvYqzPsuxxcVIpVoIfkuMHpg4xDFpD/Lqhkp8lVRgkt/m6aeLxYVP/SjfxJDuSvrUVTdvMrBG1T0y5uY+DjN8nqQU=
X-Received: by 2002:a2e:8592:: with SMTP id b18mr2444164lji.18.1567698304953; Thu, 05 Sep 2019 08:45:04 -0700 (PDT)
MIME-Version: 1.0
References: <CACsn0c=0VFPtYHkQnyjaukK3-TBS60J=cZ0LM1hVkuZg3yLG_Q@mail.gmail.com> <4279C9FF-DEF9-42D3-838A-E344307BFF88@meinberg.de> <20190905110227.GM15024@localhost> <5C81ACFB-5E40-497E-8CE5-2D152F5D048D@meinberg.de>
In-Reply-To: <5C81ACFB-5E40-497E-8CE5-2D152F5D048D@meinberg.de>
From: Watson Ladd <watsonbladd@gmail.com>
Date: Thu, 5 Sep 2019 08:44:52 -0700
Message-ID: <CACsn0cmUs9bxvsY_PCoU3PkY2e55RtdKXQq7Y=7sWp0C8S6tJA@mail.gmail.com>
To: Heiko Gerstung <heiko.gerstung@meinberg.de>
Cc: Miroslav Lichvar <mlichvar@redhat.com>, NTP WG <ntp@ietf.org>
Content-Type: multipart/alternative; boundary="00000000000094f04a0591d034ee"
Archived-At: <https://mailarchive.ietf.org/arch/msg/ntp/VAQVi3V6f8uTvsA0l0Ed6tZyhbs>
Subject: Re: [Ntp] Is one refid enough
X-BeenThere: ntp@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: <ntp.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ntp>, <mailto:ntp-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ntp/>
List-Post: <mailto:ntp@ietf.org>
List-Help: <mailto:ntp-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ntp>, <mailto:ntp-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 05 Sep 2019 15:45:16 -0000

On Thu, Sep 5, 2019, 4:08 AM Heiko Gerstung <heiko.gerstung@meinberg.de>;
wrote:

>
> > On 05.09.19, 13:04 "ntp im Auftrag von Miroslav Lichvar" <
> ntp-bounces@ietf.org
> >> if A Is stratum 1 and A->B->C->D then B would never choose D
> >> because it is stratum 4 and B itself is stratum 2.
> >
> > That's how it worked in NTPv3 and it limited the selection
> > significantly. In NTPv4 clients are allowed to synchronize to
> > sources
> > having the same or higher stratum. It has some weight in the
> > source selection (it is included in the root distance), but it
> > doesn't
> > prevent the selection.
>
> Thanks for the clarification, in this case the chain of InstanceIDs would
> also be useful to prevent loops like A-B-C-D-B ..
>

If you have no external sources what is the right answer? If you do have
external sources then a loop like this won't form.


> Best Regards,
>     Heiko
>
>
>
> >
> > --
> > Miroslav Lichvar
> >
> > _______________________________________________
> > ntp mailing list
> > ntp@ietf.org
> > https://www.ietf.org/mailman/listinfo/ntp
> >
>
> --
> Heiko Gerstung
> Managing Director
>
> MEINBERG® Funkuhren GmbH & Co. KG
> Lange Wand 9
> D-31812 Bad Pyrmont, Germany
> Phone:    +49 (0)5281 9309-404
> Fax:        +49 (0)5281 9309-9404
>
> Amtsgericht Hannover 17HRA 100322
> Geschäftsführer/Management: Günter Meinberg, Werner Meinberg, Andre
> Hartmann, Heiko Gerstung
>
> Email:
>  heiko.gerstung@meinberg.de
> Web:
>  Deutsch   https://www.meinberg.de
>  English    https://www.meinbergglobal.com
>
> Do not miss our Time Synchronization Blog:
>  https://blog.meinbergglobal.com
>
> Connect via LinkedIn:
> https://www.linkedin.com/in/heikogerstung
>
>
>
>
> _______________________________________________
> ntp mailing list
> ntp@ietf.org
> https://www.ietf.org/mailman/listinfo/ntp
>