[savi] 回复: 答复: review: draft-bi-savi-csa-00.txt
ZhangDong <zhangdong_rh@huaweisymantec.com> Thu, 21 August 2008 03:51 UTC
Return-Path: <zhangdong_rh@huaweisymantec.com>
X-Original-To: savi@core3.amsl.com
Delivered-To: savi@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id C86DC3A6832 for <savi@core3.amsl.com>; Wed, 20 Aug 2008 20:51:09 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: 1.869
X-Spam-Level: *
X-Spam-Status: No, score=1.869 tagged_above=-999 required=5 tests=[AWL=-0.377, BAYES_00=-2.599, CHARSET_FARAWAY_HEADER=3.2, MIME_8BIT_HEADER=0.3, SARE_SUB_ENC_GB2312=1.345]
Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ykSw9B+XYY9G for <savi@core3.amsl.com>; Wed, 20 Aug 2008 20:51:08 -0700 (PDT)
Received: from mta2.huaweisymantec.com (mta2.huaweisymantec.com [121.15.168.143]) by core3.amsl.com (Postfix) with ESMTP id 63AA43A6801 for <savi@ietf.org>; Wed, 20 Aug 2008 20:51:08 -0700 (PDT)
MIME-version: 1.0
Content-disposition: inline
Content-type: text/plain; charset="utf-8"
Received: from hstml02-in.huaweisymantec.com ([172.26.3.42]) by hstga02-in.huaweisymantec.com (Sun Java(tm) System Messaging Server 6.3-5.02 (built Oct 12 2007; 32bit)) with ESMTP id <0K5X00346MNVB510@hstga02-in.huaweisymantec.com> for savi@ietf.org; Thu, 21 Aug 2008 11:50:20 +0800 (CST)
Received: from huaweisymantec.com ([127.0.0.1]) by hstml02-in.huaweisymantec.com (Sun Java(tm) System Messaging Server 6.3-5.02 (built Oct 12 2007; 32bit)) with ESMTP id <0K5X005EVMNUAT00@hstml02-in.huaweisymantec.com> for savi@ietf.org; Thu, 21 Aug 2008 11:50:19 +0800 (CST)
Received: from [10.27.140.206] by hstml02-in.huaweisymantec.com (mshttpd); Thu, 21 Aug 2008 11:50:18 +0800
From: ZhangDong <zhangdong_rh@huaweisymantec.com>
To: Guang Yao <yaoa02@mails.tsinghua.edu.cn>, 'Jun Bi' <junbi@cernet.edu.cn>
Message-id: <fca2f16c324c.48ad567a@huaweisymantec.com>
Date: Thu, 21 Aug 2008 11:50:18 +0800
X-Mailer: Sun Java(tm) System Messenger Express 6.3-5.02 (built Oct 12 2007; 32bit)
Content-language: zh-CN
X-Accept-Language: zh-CN
Priority: normal
In-reply-to: <000b01c902bc$e003c360$a00b4a20$@tsinghua.edu.cn>
References: <6EC4290A25844DD38F1D89D3D608BAB0@userPC> <000b01c902bc$e003c360$a00b4a20$@tsinghua.edu.cn>
Content-transfer-encoding: quoted-printable
Cc: savi@ietf.org
Subject: [savi] 回复: 答复: review: draft-bi-savi-csa-00.txt
X-BeenThere: savi@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: Mailing list for the SAVI WG <savi.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/savi>, <mailto:savi-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/pipermail/savi>
List-Post: <mailto:savi@ietf.org>
List-Help: <mailto:savi-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/savi>, <mailto:savi-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 21 Aug 2008 03:51:09 -0000
Guang, I can understand most of your explanation. However, there is another point I want to ask. > 2 Even collision happens, it will not bring any trouble. Hosts can't > announce the ownership of this address by a DHCP solicitation. It can > just use it once to send a DHCP solicitation. It seems that a host use one temporary address to solicit another address from the DHCP server. I remember the DHCP server sends the DHCPoffer message by broadcast. So if it is, the host will not need a source address. That is to say the temporary address may be redundant. Thanks. ----------- Dong Zhang Huawei Symantec Technologies Co., Ltd TEL:010-82829263 ADDRESS:Harbour Networks P&D Center. Building 17, ZhongGuanCun Software Park, No.8, Dongbeiwang West Road, HaiDian District, Beijing, China. ----- 原始邮件 ----- 发件人: Guang Yao <yaoa02@mails.tsinghua.edu.cn> 日期: 2008年 8月 20日, 星期三, 下午8:02 主题: 答复: review: draft-bi-savi-csa-00.txt 收件人: zhangdong_rh@huaweisymantec.com 抄送: 'Jun Bi' <junbi@cernet.edu.cn> > Dear Dong Zhang, > > The collision problem of CGA address exists both in IPv4 and IPv6. In > IPv4, this problem is more serious. This draft just gives a possible > solution, and many details should be modified in the future, > especially in IPv4. > I will try to explain why we didn't put forward the collision problem > seriously. > 1 Actually, the IPv4 address doesn't have to be the hash of the CGA > identifier. It can be any valid address in the local address space. It > is just a temporary address, not a permanent address. > > 2 Even collision happens, it will not bring any trouble. Hosts can't > announce the ownership of this address by a DHCP solicitation. It can > just use it once to send a DHCP solicitation. > > 3 However, we choose that the host id should be generated by hashing > the CGA. This is because we want to control address space exhaustion. > In DHCP, one host can request the ownership of all the possible > addresses. The collision will slow the speed of application. The > gateway will check the collision of address in DHCP solicitation and > drop collision request packets. But we do think this is will brings > much trouble and maybe using other addresses to send DHCP solicitation > will be more reasonable. > > However, thanks for your proposition. Duplicate detection will be > firstly considered if we find using a duplicated temporary address > will trouble the existing mechanisms, e.g., the layer-2 protocol. > > Best Regards, > Guang Yao > -----邮件原件----- > 发件人: Jun Bi [mailto:junbi@cernet.edu.cn] > 发送时间: 2008年8月20日 17:58 > 收件人: yaoa02 > 主题: Fw: review: draft-bi-savi-csa-00.txt > > Could you reply? > thanks, > jun > ----- Original Message ----- > From: "ZhangDong" <zhangdong_rh@huaweisymantec.com> > To: "Jun Bi" <junbi@cernet.edu.cn>; "Jianping Wu" > <jianping@cernet.edu.cn>; > <yaog@netarchlab.tsinghua.edu.cn> > Cc: <savi@ietf.org> > Sent: Wednesday, August 20, 2008 5:03 PM > Subject: review: draft-bi-savi-csa-00.txt > > > Processor Bi, Wu and Yao, > > < If the node is an IPv4 node, the only different case is DHCP. The > < node cannot use a CGA address to send a DHCP solicitation. This > can > < be solved by using the address as an identifier, but not as a > < locator. The CGA address in contained in the packet as an option, > < and the host id of the IPv4 address is the hash of the CGA address. > < The signature is computed on the whole packet. > > Here, I wonder whether the host id of the IPv4 address created by the > hash > of the CGA address will bring a collision. In other words, the host > id of > the IPv4 address may already be used. Perhaps, it should has a > duplicate > detection. > > Best regards. > > ----------- > Dong Zhang > Huawei Symantec Technologies Co., Ltd > TEL:010-82829263 > ADDRESS:Harbour Networks P&D Center. Building 17, ZhongGuanCun > Software > Park, No.8, > Dongbeiwang West Road, HaiDian District, Beijing, China. > > > > >