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

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

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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.
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Date: Wed, 6 May 2020 07:11:12 +0000
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Subject: Re: [Lsr] Congestion (flow) control thoughts.
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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>rg>; 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
>