Re: [6tisch] 6P and Sf0 issue: Token to identify transactions in 6P

Qin Wang <qinwang6top@yahoo.com> Wed, 09 March 2016 15:58 UTC

Return-Path: <qinwang6top@yahoo.com>
X-Original-To: 6tisch@ietfa.amsl.com
Delivered-To: 6tisch@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id D959B12DFA6 for <6tisch@ietfa.amsl.com>; Wed, 9 Mar 2016 07:58:57 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.7
X-Spam-Level:
X-Spam-Status: No, score=-2.7 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_LOW=-0.7, RP_MATCHES_RCVD=-0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=yahoo.com
Received: from mail.ietf.org ([127.0.0.1]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id p-lP4XVijtnQ for <6tisch@ietfa.amsl.com>; Wed, 9 Mar 2016 07:58:53 -0800 (PST)
Received: from nm45-vm1.bullet.mail.bf1.yahoo.com (nm45-vm1.bullet.mail.bf1.yahoo.com [216.109.115.60]) (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 233BC12D587 for <6tisch@ietf.org>; Wed, 9 Mar 2016 07:47:59 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1457538478; bh=qucfuVK0xDzYyqazmIE/wzLW2tQeqJKV3MbfwiollxY=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:From:Subject; b=JirMdbQOvmQBYfix7LauYUemaxgV8bK79t926MoskkPBG3x/9PPg+nX63OvpCa2KGpkF9Lvh+B7PEFQTpuX2+t4IJaW5z+3uOcazh5xCkEPqADfHp5UPXV3DG3v/4NXoVglh3xufXjgEmcyLOoWMOzMAHhbFHoEdPuiu3xmyRehGSbw9f7cIPDESxX2bxPoQbiqfE32s8r6qXxeAWKYO+yYZksG+mIF/RSriDM9GpI52jKNphW6o1osLWxk00mRd8Ciz3UmUkhifEvMMOl700XnzEFYkV7OEwypl1JFpJmDU395X3gYkyyi7u4oCxjOAbkJdeg7M7sKwtKd4/1YVXw==
Received: from [98.139.170.182] by nm45.bullet.mail.bf1.yahoo.com with NNFMP; 09 Mar 2016 15:47:58 -0000
Received: from [98.139.212.250] by tm25.bullet.mail.bf1.yahoo.com with NNFMP; 09 Mar 2016 15:47:58 -0000
Received: from [127.0.0.1] by omp1059.mail.bf1.yahoo.com with NNFMP; 09 Mar 2016 15:47:58 -0000
X-Yahoo-Newman-Property: ymail-3
X-Yahoo-Newman-Id: 59714.98619.bm@omp1059.mail.bf1.yahoo.com
X-YMail-OSG: BPu4btUVM1kCPTxKoaITLaCotIIwYftRCwEeRmxIdyFM2_7bHFewTgex78de7XQ LSnGPnDtDiTWxquzopQWT3eVgjiYycUzGVvTd7dlD4kRrIKoCJ_6nJgLH5UsTa8SeYHMJt69u3hH zOSrFmEKOGafIltaa3_kBxU_GuELCUIJo_.Ql0C55NsWAPaVUkeZKOiByoaCgR0EBg68.iU4w5JT ZlxKpF_v90fKkyG1awMUGP4NGzLUnUN.QHS83_w0uwe9a693_DER1zzOWFrQU6EK.Hv38rMhG1uq r4Y83rp2Y_6F2cO1LO0TAzY0Vs7I2gkkMiw1aTVW3IjFgbFJvIX6muebmYblhkPSHLtc9M6bCz8L 0AbOzyZMTSIANbLp578Lgjls1Q5tXIA5ZTLdAlOl0llDjcO9ElYMslHzWZaio9G0ByMs2ML4zbhr _oI2W6IjPfd_oMSnn5mB18jMo_XpbJiNxUkOxzfrangr51GmMHUvGiLVpKJd0uvSCwHqLdNkyZXo Q94zpcnx5oqQlbM01
Received: by 76.13.27.55; Wed, 09 Mar 2016 15:47:57 +0000
Date: Wed, 09 Mar 2016 15:47:46 +0000
From: Qin Wang <qinwang6top@yahoo.com>
To: "Pascal Thubert (pthubert)" <pthubert@cisco.com>
Message-ID: <799700602.6733178.1457538467013.JavaMail.yahoo@mail.yahoo.com>
In-Reply-To: <83F03D1D-FC7D-4502-80D5-9793DDE02DDF@cisco.com>
References: <83F03D1D-FC7D-4502-80D5-9793DDE02DDF@cisco.com>
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="----=_Part_6733177_290907957.1457538466999"
Archived-At: <http://mailarchive.ietf.org/arch/msg/6tisch/gM5UfiKrtw88CCpBSYgSHC9-cys>
Cc: "6tisch@ietf.org" <6tisch@ietf.org>, "Prof. Diego Dujovne" <diego.dujovne@mail.udp.cl>, Tengfei Chang <tengfei.chang@gmail.com>, Tero Kivinen <kivinen@iki.fi>
Subject: Re: [6tisch] 6P and Sf0 issue: Token to identify transactions in 6P
X-BeenThere: 6tisch@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
Reply-To: Qin Wang <qinwang6top@yahoo.com>
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: <https://mailarchive.ietf.org/arch/browse/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, 09 Mar 2016 15:58:58 -0000

Pascal,
I can see your point. Token is useful for Parent to distinguish Retry from new Request by the Child. 
But, I have a stupid question: is it reasonable to allow the Child to ask more cells before it gets Response to what it already asked?
ThanksQin 

    On Wednesday, March 9, 2016 2:13 AM, Pascal Thubert (pthubert) <pthubert@cisco.com> wrote:
 

 Hello Qin:
Token 1 needs to be the same as token 2 when it is a retry. That's the whole point.
In your second case, say this is a child asking for a cell:
- If this is a time out because the response from the parent was lost, the parent should respond with the same cell as in the lost message. 
- But if the child got the response and still needs more bandwidth, then the parent needs to allocate a second cell.
How does the parent know?
The main point of the sequence number is to be able to correlate the retry. 
As it goes, it also enables to avoid the serialization of requests but I agree that is a non goal today.

Regards,
Pascal
Le 8 mars 2016 à 22:10, Qin Wang <qinwang6top@yahoo.com> a écrit :


Hi all,
I'm not convinced that token is necessary yet. From the discussion in the last WG meeting, we have agreed that the Token is used in the 6P message exchange between neighbors. Based on the agreement, let's consider the two following scenarios.
(1) nodeA send ADD_Request(token=1) to nodeB, and not receive Response from nodeB before Timeout. Then, nodeA send ADD_Request(token=2) to nodeB, and receive Response(token=2) from nodeB. 
(2) nodeA send ADD_Request to nodeB, and not receive Response from nodeB before Timeout. Then nodeA send ADD_Request to nodeB again, and receive Response from nodeB.

The question is if it is possible for nodeA to receive Response(token=1) from nodeB later in (1). Since nodeA will send the second ADD_Request after Timeout, I don't think it could happen. If I'm correct, I think the two sequences function similarly. Thus, I wonder if it is necessary to have the Token
What do you think?
ThanksQin


On Tuesday, March 8, 2016 10:10 AM, Pascal Thubert (pthubert) <pthubert@cisco.com> wrote:


Oh yes, Tero,

we agree on the bottom line and on your points.

Cheers,

Pascal

> -----Original Message-----
> From: Tero Kivinen [mailto:kivinen@iki.fi]
> Sent: mardi 8 mars 2016 15:50
> To: Pascal Thubert (pthubert) <pthubert@cisco.com>
> Cc: Tengfei Chang <tengfei.chang@gmail.com>;6tisch@ietf.org; Prof. Diego
> Dujovne <diego.dujovne@mail.udp.cl>
> Subject: RE: [6tisch] 6P and Sf0 issue: Token to identify transactions in 6P
> 
> Pascal Thubert (pthubert) writes:
> > But this is another discussion entirely. It is about the transaction
> > that associates new timeslots to a bundle and why we need a
> > correlator, or transaction ID. I was explaining that if the parent
> > wait for the ack to allocate a slot that was negotiated, and there is
> > no flow after that, then if the ack is lost the child thinks the slot
> > is allocated and the parent does not. The child may start using it
> > wrongly.
> 
> Which is why you should not use ACK for anything like that, but instead use
> application level messages for that kind of things.
> 
> > The point behind this is that if the transaction does not complete, it
> > must be retried from scratch with the same sequence, or it must time
> > out and roll back.
> 
> Receiving or not receiving ACK should not cause transaction to complete or
> not to complete, there must be some kind of application level message to
> indicate that it was successful if that information is needed in the peers.
> --
> kivinen@iki.fi

_______________________________________________
6tisch mailing list
6tisch@ietf.org
https://www.ietf.org/mailman/listinfo/6tisch