[P2PSIP] RFC6940: Chord total order definition

Evgeny <xramtsov@gmail.com> Tue, 16 October 2018 07:52 UTC

Return-Path: <xramtsov@gmail.com>
X-Original-To: p2psip@ietfa.amsl.com
Delivered-To: p2psip@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 4BD5F126CB6 for <p2psip@ietfa.amsl.com>; Tue, 16 Oct 2018 00:52:41 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2
X-Spam-Level:
X-Spam-Status: No, score=-2 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, RCVD_IN_DNSWL_NONE=-0.0001, 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 MaSw8Otiw_9j for <p2psip@ietfa.amsl.com>; Tue, 16 Oct 2018 00:52:39 -0700 (PDT)
Received: from mail-lf1-x135.google.com (mail-lf1-x135.google.com [IPv6:2a00:1450:4864:20::135]) (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 EB46B12D4EA for <p2psip@ietf.org>; Tue, 16 Oct 2018 00:52:38 -0700 (PDT)
Received: by mail-lf1-x135.google.com with SMTP id n14-v6so4271220lfe.6 for <p2psip@ietf.org>; Tue, 16 Oct 2018 00:52:38 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:subject:to:message-id:mime-version; bh=fmblzLhAQt4eSWThkfE6LWRqT6iLHnzDFKOK8qVceFI=; b=dil5Pp1wr0I0wEL0cQZIDM/jzoCW3nkdblAJfkV7MxIAF9TRdqEDRq4f94xH9pMI0h 2dZUztdPU9wcFyPP+w4GTu0pFle+xOybEmQfUFGoTHTTPh79M6iWLniyk7dvkBMbAjeT D/Dj+DF4zor10JDgKrxcvYUthh4xIfEoFnHxRN8Gl1OOl6Nfuubt3EHozU1+5QXIRVgp 1tuaq//cAegNYDljcJjWKfopTqYdF4wDeyK/I1Ud5dbSr4sGFbXzhayNLhAGmgEzHji3 oHDmNd4SdKtI9RBh43FM8s7UM7L+I0OTvnZBTatwnVPtyoJIoQsE1WjZl/n2TeMvMOyj vEAg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:subject:to:message-id:mime-version; bh=fmblzLhAQt4eSWThkfE6LWRqT6iLHnzDFKOK8qVceFI=; b=R99jdC2UC0gHK2aRg0WZTzhXwHDTMglGYryQJkOSgwreM8oMl68u4QoBhWkhbJzg7E sAa2cdKeENI8F++k00uq94KEeE37WNw3rwfcVh6Il8qGVX8XymmrzYHIsVht57/P+R2M aA28SgB74K0kBLAnBeexqXcrzGLfv/EbMpjW/p0MH8jBYSshCXYwHQqydSCyVvOH6yiM jGrLP7V3xeaxeoUacz+JO9X/eZFlAyDBuGO0AV2FOqiw3+HAPhmuvS71xLj7ynQCFoIP JzoRGqvJ1K7X5zfHHvlNGq19OYErJD0Nw2pafQfkxGNAPMhOABu3JAoziEkksVG+6qek 1AdQ==
X-Gm-Message-State: ABuFfohgarVAZMJqzFGpyk+i8EYC+JGb6UlXoSJmGcMHY6HOzl0UBRfc cYLnsv7S16/09/ioP8LzRIgCFpzI
X-Google-Smtp-Source: ACcGV60OmXTSHiJI0x8O12zpL7JuFRYGsLPs8FoRT4qYPxLu0KfO/hfwq4o2Olxm8xQ0nA/utI3P1Q==
X-Received: by 2002:a19:2d16:: with SMTP id k22-v6mr12521513lfj.134.1539676356400; Tue, 16 Oct 2018 00:52:36 -0700 (PDT)
Received: from [192.168.1.102] ([31.181.13.56]) by smtp.gmail.com with ESMTPSA id z5-v6sm3023903lji.65.2018.10.16.00.52.35 for <p2psip@ietf.org> (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 16 Oct 2018 00:52:35 -0700 (PDT)
Date: Tue, 16 Oct 2018 10:52:34 +0300
From: Evgeny <xramtsov@gmail.com>
To: p2psip@ietf.org
Message-Id: <1539676354.1194.1@smtp.gmail.com>
X-Mailer: geary/0.12.2
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Archived-At: <https://mailarchive.ietf.org/arch/msg/p2psip/ZwgjvypdOnkfqgEQpcrVlnT7h78>
Subject: [P2PSIP] RFC6940: Chord total order definition
X-BeenThere: p2psip@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Peer-to-Peer SIP working group discussion list <p2psip.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/p2psip>, <mailto:p2psip-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/p2psip/>
List-Post: <mailto:p2psip@ietf.org>
List-Help: <mailto:p2psip-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/p2psip>, <mailto:p2psip-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 16 Oct 2018 07:52:41 -0000

Hi, IETF people! :)

Excuse my ignorance: I'm not a big specialist in Chord or DHTs in 
general.
I would like to clarify one thing:
How is the total order [1] defined in the Chord ring? Is it a simple 
order
of integer numbers? But in this case some nodes (the ones "closest to 
zero")
will not have successors or predecessors and, thus, the ring will 
always be
partitioned. If the order is defined using the "wrapping around zero", 
then
any i'th successor of node X will be its j'th predecessor and, thus, 
for example,
if there are only 3 nodes (besides X) and node X needs to keep 3 
successors
and 3 predecessors, then X's successors list will be equal to its 
predecessors list?

In other words, could someone please provide the exact definition, like:
x < y <=> when?

I feel, this is not an internal implementation detail, because a node 
needs
to send its neighbors list and fingers table, so this should be 
interoperable.

[1] https://en.wikipedia.org/wiki/Total_order