IETF Logo Mail Archive

Re: [Roll] Ralph's DISCUSS on MRHOF spec

Philip Levis <pal@cs.stanford.edu> Wed, 06 June 2012 14:42 UTC

Return-Path: <pal@cs.stanford.edu>
X-Original-To: roll@ietfa.amsl.com
Delivered-To: roll@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8D25621F8842 for <roll@ietfa.amsl.com>; Wed, 6 Jun 2012 07:42:48 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.599
X-Spam-Level:
X-Spam-Status: No, score=-6.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, RCVD_IN_DNSWL_MED=-4]
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 VLbyEbMhmuCp for <roll@ietfa.amsl.com>; Wed, 6 Jun 2012 07:42:48 -0700 (PDT)
Received: from cs-smtp-1.Stanford.EDU (cs-smtp-1.Stanford.EDU [171.64.64.25]) by ietfa.amsl.com (Postfix) with ESMTP id 14B3C21F884C for <roll@ietf.org>; Wed, 6 Jun 2012 07:42:48 -0700 (PDT)
Received: from 23-24-194-1-static.hfc.comcastbusiness.net ([23.24.194.1] helo=[192.168.1.106]) by cs-smtp-1.Stanford.EDU with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.76) (envelope-from <pal@cs.stanford.edu>) id 1ScHRe-0006NT-NS; Wed, 06 Jun 2012 07:42:46 -0700
Mime-Version: 1.0 (Apple Message framework v1257)
Content-Type: text/plain; charset="us-ascii"
From: Philip Levis <pal@cs.stanford.edu>
In-Reply-To: <8EFE80AF-3E7C-494E-8237-C63E6ECDAE7E@gmail.com>
Date: Wed, 06 Jun 2012 07:43:04 -0700
Content-Transfer-Encoding: quoted-printable
Message-Id: <53E28E3B-4C73-4BD3-BCFE-2C669FC3FA1D@cs.stanford.edu>
References: <831338825.521366.1338009982543.JavaMail.root@mail17.pantherlink.uwm.edu> <8EFE80AF-3E7C-494E-8237-C63E6ECDAE7E@gmail.com>
To: Ralph Droms <rdroms.ietf@gmail.com>
X-Mailer: Apple Mail (2.1257)
X-Scan-Signature: 764eb63bb4c91aa8ddbf2de6f9e489d2
Cc: Stiemerling Martin <mstiemerling@googlemail.com>, roll <roll@ietf.org>, Michael Richardson <mcr@sandelman.ca>, Haberman Brian <brian@innovationslab.net>
Subject: Re: [Roll] Ralph's DISCUSS on MRHOF spec
X-BeenThere: roll@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Routing Over Low power and Lossy networks <roll.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/roll>, <mailto:roll-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/roll>
List-Post: <mailto:roll@ietf.org>
List-Help: <mailto:roll-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/roll>, <mailto:roll-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 06 Jun 2012 14:42:48 -0000

Responses inline.

On Jun 4, 2012, at 9:31 AM, Ralph Droms wrote:

>> 
> 
> My question here is why a single objective function "MRHOF" is defined to use several different metrics.  My understanding is that any specific RPL instance will use one metric as its "selected metric" for MRHOF.  Another way to organize the objective functions would be to define a different OF number for each metric, binding the OF number to the selected metric.

This was a design decision made early in RPL. There were two options: OFs are metric-specific, or OFs can be general with respect to metrics. The design team concluded the second approach was better, as the former would lead to a possibly huge number of OFs that would be hard to manage.

Phil

v2.29.0 | Report a Bug | By Email | System Status