Re: [Lsr] Congestion (flow) control thoughts.

"Gengxuesong (Geng Xuesong)" <gengxuesong@huawei.com> Wed, 06 May 2020 07:11 UTC

Return-Path: <gengxuesong@huawei.com>
X-Original-To: lsr@ietfa.amsl.com
Delivered-To: lsr@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id E61413A07A3 for <lsr@ietfa.amsl.com>; Wed, 6 May 2020 00:11:18 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.898
X-Spam-Level:
X-Spam-Status: No, score=-1.898 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
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 XJQgCOnZepYz for <lsr@ietfa.amsl.com>; Wed, 6 May 2020 00:11:17 -0700 (PDT)
Received: from huawei.com (lhrrgout.huawei.com [185.176.76.210]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id A42653A07A5 for <lsr@ietf.org>; Wed, 6 May 2020 00:11:17 -0700 (PDT)
Received: from lhreml724-chm.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id 92261B1B9D9B3743ECBC for <lsr@ietf.org>; Wed, 6 May 2020 08:11:15 +0100 (IST)
Received: from dggeme701-chm.china.huawei.com (10.1.199.97) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.1913.5; Wed, 6 May 2020 08:11:14 +0100
Received: from dggeme752-chm.china.huawei.com (10.3.19.98) by dggeme701-chm.china.huawei.com (10.1.199.97) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1913.5; Wed, 6 May 2020 15:11:12 +0800
Received: from dggeme752-chm.china.huawei.com ([10.6.80.76]) by dggeme752-chm.china.huawei.com ([10.6.80.76]) with mapi id 15.01.1913.007; Wed, 6 May 2020 15:11:12 +0800
From: "Gengxuesong (Geng Xuesong)" <gengxuesong@huawei.com>
To: "tony.li@tony.li" <tony.li@tony.li>
CC: Christian Hopps <chopps@chopps.org>, "lsr@ietf.org" <lsr@ietf.org>
Thread-Topic: [Lsr] Congestion (flow) control thoughts.
Thread-Index: AQHWHiEz1dI/yoz7M0KHaDn4nVfYx6iQ5nmAgABsaICACVON4A==
Date: Wed, 06 May 2020 07:11:12 +0000
Message-ID: <21e4996c370b475db4eb4e7ffc298434@huawei.com>
References: <sa6r1w6h446.fsf@stubbs.int.chopps.org> <8016231f9ff94bd2b0f5ef989608922f@huawei.com> <DD8160ED-5131-40D3-AA12-D4810C26B9BA@tony.li>
In-Reply-To: <DD8160ED-5131-40D3-AA12-D4810C26B9BA@tony.li>
Accept-Language: zh-CN, en-US
Content-Language: zh-CN
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [10.108.148.72]
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
X-CFilter-Loop: Reflected
Archived-At: <https://mailarchive.ietf.org/arch/msg/lsr/Z3vD8vutDOHD4r9CmOU9-1a8pok>
Subject: Re: [Lsr] Congestion (flow) control thoughts.
X-BeenThere: lsr@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Link State Routing Working Group <lsr.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/lsr>, <mailto:lsr-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/lsr/>
List-Post: <mailto:lsr@ietf.org>
List-Help: <mailto:lsr-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/lsr>, <mailto:lsr-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 06 May 2020 07:11:19 -0000

Hi Tony,

Thank you for your explanation. Please find my comments inline.

Best Regards
Xuesong

> -----Original Message-----
> From: Tony Li [mailto:tony1athome@gmail.com] On Behalf Of tony.li@tony.li
> Sent: Friday, May 1, 2020 12:16 AM
> To: Gengxuesong (Geng Xuesong) <gengxuesong@huawei.com>
> Cc: Christian Hopps <chopps@chopps.org>; lsr@ietf.org
> Subject: Re: [Lsr] Congestion (flow) control thoughts.
>  
> 
> I consider flow control and congestion control to be separate, but similar
> problems.
> 
> Flow control is about creating a single control loop between a single
> transmitter and single receiver.
> 
> Congestion control is about creating multiple interacting control loops between
> multiple transmitters and multiple receivers.

<Xuesong> I think there is no need to distinguish the concept of flow control and congestion control, considering that the core idea is the same: monitor the sending rate to match the capability of the bottleneck, no matter there are competitors or not. And the control loop is necessary in both case. 

> In our draft, we are proposing other feedback mechanisms.

<Xuesong> Thank you for explaining about the bottleneck of flooding and different cc solutions that are under discussion. It is helpful and I will read the drafts. 
There is still one more question left in the previous email: " What is the criteria of comparing different solutions?". I think this is crucial for further discussion and comparative tests. I notice that in Bruno's data, some parameters are mentioned, such as " Duration"," LSP/second"," avg inter-LSP delay", "retransmission time". I'm wondering whether it is able to choose a better solution through these parameters. If not, what should be added or considered. (Some other issues are also considered when choosing cc mechanism in layer 4, such as: fairness among flows, co-existence with other cc mechanism .. )


> Tony
>