[6tisch] About the paper "Packet Reservation Multiple Access for Local Wireless Communications"

"Prof. Diego Dujovne" <diego.dujovne@mail.udp.cl> Wed, 04 December 2013 18:47 UTC

Return-Path: <diego.dujovne@mail.udp.cl>
X-Original-To: 6tisch@ietfa.amsl.com
Delivered-To: 6tisch@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 652141AE172 for <6tisch@ietfa.amsl.com>; Wed, 4 Dec 2013 10:47:58 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.977
X-Spam-Level:
X-Spam-Status: No, score=-1.977 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, FM_FORGED_GMAIL=0.622, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7] autolearn=ham
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 0VtI6sPElZXz for <6tisch@ietfa.amsl.com>; Wed, 4 Dec 2013 10:47:55 -0800 (PST)
Received: from mail-wg0-f43.google.com (mail-wg0-f43.google.com [74.125.82.43]) by ietfa.amsl.com (Postfix) with ESMTP id 8BB6B1A802A for <6tisch@ietf.org>; Wed, 4 Dec 2013 10:47:54 -0800 (PST)
Received: by mail-wg0-f43.google.com with SMTP id k14so12688407wgh.34 for <6tisch@ietf.org>; Wed, 04 Dec 2013 10:47:51 -0800 (PST)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:date:message-id:subject:from:to :content-type; bh=WuPQyBQZx5JxpbbZrQ2TD5yfUeTlJ5jQn3imGKK2YDA=; b=Jurkk0s181/W+QEstIMggjHZIH0JXIK4as3xGYsTQHwlyydWX8bL4FkK4yXvM5Y/6E NjCcC9XlZQSoodD4I6MK+mSoNgjEy8t/6IJfNuMqrRkiGa+ehSr7scrZKxKQXte4NIit q5L0/KwCNXk7dMf7VV9ZJS1kzCCNI4iEi70u2Ch0d0XEnJPSuL3qWCyQACEoYZI4ZaQQ ltXyIGEvVL5cEgLNDBLg3RG2B0MwwxxvEwGjpmcsXh7j0n1M4INoFPTZX/AilKP0i7SA UFMAMTsbnHHAYpIc0FEYFZ90AhQwBmc4MCtHTYrac+x+FKhMffwUBlwkS2+8ftaSX9RD SPaw==
X-Gm-Message-State: ALoCoQks+EHsTDWWw5ilb8TIUwpPrrOvwztrhxpMtigt5UUNEmhZBH1rfiyNa5jqhDZX367Nz9vG
MIME-Version: 1.0
X-Received: by 10.194.79.74 with SMTP id h10mr801345wjx.86.1386182871569; Wed, 04 Dec 2013 10:47:51 -0800 (PST)
Received: by 10.194.122.103 with HTTP; Wed, 4 Dec 2013 10:47:51 -0800 (PST)
Date: Wed, 04 Dec 2013 16:47:51 -0200
Message-ID: <CAH7SZV-JEEMS13YXbiHMsghTi7hBYyEr8re1oYGiZVePppPTCA@mail.gmail.com>
From: "Prof. Diego Dujovne" <diego.dujovne@mail.udp.cl>
To: "6tisch@ietf.org" <6tisch@ietf.org>, Thomas Watteyne <watteyne@eecs.berkeley.edu>
Content-Type: multipart/alternative; boundary="047d7bb04a12a7698804ecb9d9aa"
Subject: [6tisch] About the paper "Packet Reservation Multiple Access for Local Wireless Communications"
X-BeenThere: 6tisch@ietf.org
X-Mailman-Version: 2.1.15
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" <6tisch.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/6tisch>, <mailto:6tisch-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/6tisch/>
List-Post: <mailto:6tisch@ietf.org>
List-Help: <mailto:6tisch-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/6tisch>, <mailto:6tisch-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 04 Dec 2013 18:47:58 -0000

Dear all,
           I went through the paper "Packet Reservation Multiple Access for
Local Wireless Communications"*, *recommended by Prof. Wolisz. As far as I
can understand, the paper
defines:
- Subsec. A: Information packet categories: Periodic and Random.
- "Information Frames" on sec. II, subsect. B.  On the proposed topology
(Base Station - Terminals) each terminal has a frame reservation register,
with one bit per slot in the frame.
- Finally, on subsec. D, "Reservations", it states that the base station
(as a centralized system)
provides an ACK to the source station after a successful reception. When
the source station
receives the ACK to a periodic Information packet, it reserves that slot in
future frames
for its exclusive use.
When a station stops sending periodic Information packets, the base station
broadcasts
that this slot is free in the ACK packet, so the stations can contend for
that slot.
On the other hand, Random Information packets do not reserve a slot, they
only
contend until a transmission succeeds on unreserved slots.

My point of view is that our goal is not to use contention as a reservation
mechanism, to support the concept of deterministic networking.

On the other hand, if there is no contention, and there is a collision,
(except something like the Capture Effect phenomena happens) none of the
packets will be acknowledged.

If there is no contention, but there is no collision, then, the solution
would be "First arrived, first served" to reserve a slot, while the lack of
periodic update from the terminal may free the slot.

Any thoughts?

                                                 Diego





-- 
DIEGO DUJOVNE
Académico Escuela de Ingeniería en Informática y Telecomunicaciones
Facultad de Ingeniería UDP
www.ingenieria.udp.cl
(56 2) 676 8125