Re: [6tsch] set DAGRank to Join Priority

Qin Wang <qinwang@berkeley.edu> Fri, 27 September 2013 20:44 UTC

Return-Path: <qinwang@berkeley.edu>
X-Original-To: 6tsch@ietfa.amsl.com
Delivered-To: 6tsch@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 2250D21F9BC1 for <6tsch@ietfa.amsl.com>; Fri, 27 Sep 2013 13:44:39 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.64
X-Spam-Level:
X-Spam-Status: No, score=-2.64 tagged_above=-999 required=5 tests=[AWL=0.336, BAYES_00=-2.599, FM_FORGED_GMAIL=0.622, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ajte29uM8ClO for <6tsch@ietfa.amsl.com>; Fri, 27 Sep 2013 13:44:35 -0700 (PDT)
Received: from mail-ie0-f178.google.com (mail-ie0-f178.google.com [209.85.223.178]) by ietfa.amsl.com (Postfix) with ESMTP id 4D64621F9B21 for <6tsch@ietf.org>; Fri, 27 Sep 2013 13:44:25 -0700 (PDT)
Received: by mail-ie0-f178.google.com with SMTP id to1so5038800ieb.23 for <6tsch@ietf.org>; Fri, 27 Sep 2013 13:44:24 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=C8pJi7niYVk/+D9miofz2tyRVqsFtPb71L7UyevxnxI=; b=mZMbtgadCQ17gTQv2npW41z5J+4zjimuHqG7rJF45DPRTVNzrh+JnA3aKm7pn+TP// ZbNweMoJWp2Qm7pSQtC7m/L0vj9eh+/iQQapXwvRdik9fQD7Bqc4saKQu5AexW78fag3 Vt4N5xOOkoPhYTIZhRyi78zfB7pRaawkKyCMmFjZnE83+jD1X1qhejRukVn/Klou6gVV kekX0IYChcn9AiQw/eAE/hJ876fJkvfA59IPuVCyb+xZ3h7H/KXa1ki3hHd/+Qzxjjk1 /4qqiBIyB/KzMgcGPiXYca9z9hi8hEYd5KwpMj77/RsvfJvq2gT5UhaogZwQB1jx6GWX sYPg==
X-Gm-Message-State: ALoCoQlwM6Gv2KSG9ZKvjxoihib6NOQTkpp4nTSVaeU1VML+e8iNiFrG+gVuyu3w0tTU+kUXwo6n
MIME-Version: 1.0
X-Received: by 10.50.60.5 with SMTP id d5mr3993523igr.26.1380314663695; Fri, 27 Sep 2013 13:44:23 -0700 (PDT)
Received: by 10.64.130.234 with HTTP; Fri, 27 Sep 2013 13:44:23 -0700 (PDT)
In-Reply-To: <CALEMV4Zom6wW6ByhB3zMwJRt1NpqmeFbe13NuUbrFSWz=pNGhw@mail.gmail.com>
References: <CAAzoce5GiY8zsD4aSaSeWB19Se3fwcTTd8wpqRTC0rAonncUkg@mail.gmail.com> <CALEMV4Zom6wW6ByhB3zMwJRt1NpqmeFbe13NuUbrFSWz=pNGhw@mail.gmail.com>
Date: Sat, 28 Sep 2013 04:44:23 +0800
Message-ID: <CAAzoce4zvg0_igrE=U-afgf1iOsGmSUo78kjL-z7tmLVnWRBwg@mail.gmail.com>
From: Qin Wang <qinwang@berkeley.edu>
To: Xavier Vilajosana Guillen <xvilajosana@eecs.berkeley.edu>
Content-Type: multipart/alternative; boundary=047d7b10c77f35424c04e7638d65
Cc: "6tsch@ietf.org" <6tsch@ietf.org>
Subject: Re: [6tsch] set DAGRank to Join Priority
X-BeenThere: 6tsch@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: "Discuss link layer model for Deterministic IPv6 over the TSCH mode of IEEE 802.15.4e, and impacts on RPL and 6LoWPAN such as resource allocation" <6tsch.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/6tsch>, <mailto:6tsch-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/6tsch>
List-Post: <mailto:6tsch@ietf.org>
List-Help: <mailto:6tsch-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/6tsch>, <mailto:6tsch-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 27 Sep 2013 20:44:39 -0000

Xavi,

Let's take the example in your draft to see what the problem is. Please
point out if I'm wrong.
+-------+
     |   0   | R(0)=0
     |       | DAGRank(R(0)) = 0
     +-------+
         |
         |
     +-------+
     |   1   | R(1)=R(0)+683=683
     |       | DAGRank(R(1)) = 2
     +-------+
         |
         |
     +-------+
     |   2   | R(2)=R(1)+683=1366
     |       | DAGRank(R(2)) = 5
     +-------+
         |
         |
     +-------+
     |   3   | R(3)=R(2)+683=2049
     |       | DAGRank(R(3)) = 8
     +-------+
         |
         |
     +-------+
     |   4   | R(4)=R(3)+683=2732
     |       | DAGRank(R(4)) = 10
     +-------+
         |
         |
     +-------+
     |   5   | R(5)=R(4)+683=3415
     |       | DAGRank(R(5)) = 13
     +-------+

>From the example, you can see R(n) is a 2-byte integer, and DAGRank is
always the higher byte of the 2byte integer, because minHopRankIncrease =
256.

If set JoinPriority = DAGRank, then it is possible JoinPriority> 0x3f
(although it unlikely happens often), out of its range.
If set JoinPriority[5:0] = DAGRank[7:2], (Is it your suggestion?), a new
node may found many existing nodes with same JoinPriority in received EB.
In another word, the JoinPriority can not provide information about
preferring joining. Right?

I haven't had good solution for it. So, I hope the range 0x00~0x3f is not a
"MUST" in IEEE802.15.4e.

What  do you think?
Qin




On Sat, Sep 28, 2013 at 2:30 AM, Xavier Vilajosana Guillen <
xvilajosana@eecs.berkeley.edu> wrote:

> Hi Qin,
>
> after thinking a little bit on that maybe we can use the higher byte of
> the rank for that. that is  rank>>8, the higher byte is a monotonically
> increasing counter. As each hop is <<8 (due to minhopRankIncrease) we can
> have the sense of higher join priority as higher the rank.
>
> In addition having if we have the limitation of 0x3F, this means that we
> will support Join priorities up to 0x3F that translated to ranks are
> 0x3F<<8 (big number) ..
>
> just thoughts...
> X
>
>
> On Fri, Sep 27, 2013 at 10:30 AM, Qin Wang <qinwang@berkeley.edu> wrote:
>
>> Hi Thomas,
>>
>> I think with OF0 the DAGRank is uint8. But, in the Table 52b of
>> IEEE802.15.4e, the range of Join Priority is 0x00~0x3f. If the range is a
>> "MUST", we have to have a function mapping a DAGRank in 0x00~0xff to a
>> JoinPriority in 0x00~0x3f. Correct?
>>
>> Would you please confirm with some expertise in IEEE802.15.4e if the
>> range 0x00~0x3f is a MUST or not?
>>
>> Thanks
>> Qin
>>
>> _______________________________________________
>> 6tsch mailing list
>> 6tsch@ietf.org
>> https://www.ietf.org/mailman/listinfo/6tsch
>>
>>
>