Re: [ppsp] comments on draft-ietf-ppsp-peer-protocol-03.txt

Arno Bakker <arno@cs.vu.nl> Tue, 06 November 2012 12:42 UTC

Return-Path: <a.bakker@vu.nl>
X-Original-To: ppsp@ietfa.amsl.com
Delivered-To: ppsp@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A483E21F8846 for <ppsp@ietfa.amsl.com>; Tue, 6 Nov 2012 04:42:55 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.554
X-Spam-Level:
X-Spam-Status: No, score=-1.554 tagged_above=-999 required=5 tests=[AWL=-0.050, BAYES_00=-2.599, HELO_EQ_NL=0.55, HOST_EQ_NL=1.545, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([64.170.98.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dXeG5QoiOudG for <ppsp@ietfa.amsl.com>; Tue, 6 Nov 2012 04:42:55 -0800 (PST)
Received: from mailin.vu.nl (mailin.vu.nl [130.37.164.18]) by ietfa.amsl.com (Postfix) with ESMTP id DC5EF21F891A for <ppsp@ietf.org>; Tue, 6 Nov 2012 04:42:54 -0800 (PST)
Received: from PEXHB012B.vu.local (130.37.236.67) by mailin.vu.nl (130.37.164.18) with Microsoft SMTP Server (TLS) id 14.2.298.4; Tue, 6 Nov 2012 13:42:49 +0100
Received: from [130.161.211.249] (130.37.238.20) by mails.vu.nl (130.37.236.67) with Microsoft SMTP Server (TLS) id 14.2.298.4; Tue, 6 Nov 2012 13:42:49 +0100
Message-ID: <509905D6.2050901@cs.vu.nl>
Date: Tue, 06 Nov 2012 13:43:02 +0100
From: Arno Bakker <arno@cs.vu.nl>
User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:11.0) Gecko/20120312 Thunderbird/11.0
MIME-Version: 1.0
To: zhangyunfei <zhangyunfei@chinamobile.com>
References: <20121022054506.24206.72390.idtracker@ietfa.amsl.com> <201210221507482101757@chinamobile.com>, <5084F1F7.4020002@cs.vu.nl> <2012110216294380861230@chinamobile.com>
In-Reply-To: <2012110216294380861230@chinamobile.com>
Content-Type: text/plain; charset="ISO-8859-15"; format="flowed"
Content-Transfer-Encoding: 7bit
X-Originating-IP: [130.37.238.20]
Cc: ppsp <ppsp@ietf.org>
Subject: Re: [ppsp] comments on draft-ietf-ppsp-peer-protocol-03.txt
X-BeenThere: ppsp@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
Reply-To: arno@cs.vu.nl
List-Id: discussing to draw up peer to peer streaming protocol <ppsp.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ppsp>, <mailto:ppsp-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/ppsp>
List-Post: <mailto:ppsp@ietf.org>
List-Help: <mailto:ppsp-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ppsp>, <mailto:ppsp-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 06 Nov 2012 12:42:55 -0000

Hi Yunfei et al.

On 02/11/2012 09:29, zhangyunfei wrote:
> Hi Arno (Speaking individually),
> I've read the draft and the following is my comments:
> 1) The effect of "choke/unchoke" is not very clear in the draft. Will
> this increase the transfer efficiency?

The CHOKE/UNCHOKE is a mechanism that deployments/policies on top of the 
base protocol may choose to use. It will make an implementation simpler. 
Imagine you are connected to a good peer (i.e., one that sends DATA 
back). If the good peer sends you a CHOKE, you immediately know that he 
is not going to respond anymore and you should look for a different peer 
to download from. No need to retry REQUESTs.

> 3) Is it better to combine section 5,6, 7 into security consideration
> section as all these 3 sections involve identifying the data is from the
> reliable source/peers, which is related to security more or less. What's
> more, it makes the draft better structured.

I personally see two issues. First, it means content integrity isn't 
discussed before we present the protocol options and UDP encapsulation. 
Second, the Security Considerations section will become roughly 20 pages 
out of a 47 total which sounds a bit unbalanced to me. But you have more 
experience in this than I, so please let me know what is common.

CU,
      Arno