Re: The usecase of the BFD application

Jeffrey Haas <jhaas@pfrc.org> Tue, 12 November 2019 08:13 UTC

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Date: Tue, 12 Nov 2019 03:17:24 -0500
From: Jeffrey Haas <jhaas@pfrc.org>
To: Weiqiang Cheng <chengweiqiang@chinamobile.com>
Cc: bfd-chairs@ietf.org, rtg-bfd@ietf.org, =?utf-8?B?J+eOi+eRnumbqic=?= <wangruixue@chinamobile.com>, liu.aihua@zte.com.cn
Subject: Re: The usecase of the BFD application
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Weiqiang Cheng,

On Tue, Nov 12, 2019 at 03:56:23PM +0800, Weiqiang Cheng wrote:
> We will cover those points in the presentation.  

Thank you.

> We just have a quick review on TR-146, where it says that Echo function is 
> used and the destination IP is set to an IP address of the sender (the 
> latter is similar to the One-arm idea) for unidirectional failure detection.
>  
> But based on our understanding, BFD Echo requires that the receiver must be 
> able to recognize and process BFD control packet. One-arm idea assumes that 
> the receiving end is completely unaware of BFD, it just forwards the packet 
> based on routing. This is very useful in the scenario (e.g., Data Center or 
> 4G/5G Telecom Cloud) where large number of BFD sessions may be needed, and 
> the receiver cannot handle too much BFD sessions with limited resource.  

TR-146 similarly does not use any BFD signaling, so it is very similar
(identical?) to your Internet-Draft.  

> The idea is straight forward, we will include more details (e.g., session 
> establishment, state machine, YANG etc.) in the next version.

Thank you.

-- Jeff