Re: Adoption call for draft-cw-bfd-unaffiliated-echo (ending 16 August, 2020)

Weiqiang Cheng <> Mon, 17 August 2020 06:07 UTC

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From: "Weiqiang Cheng" <>
To: "'Santosh P K'" <>, "'Jeffrey Haas'" <>
Cc: "'rtg-bfd WG'" <>
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Subject: Re: Adoption call for draft-cw-bfd-unaffiliated-echo (ending 16 August, 2020)
Date: Mon, 17 Aug 2020 14:07:33 +0800
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Hi Santosh,

Thanks for your review and good questions.

Please see inline responses with <Weiqiang>.

Best Regards,




发件人: Rtg-bfd [] 代表 Santosh P K
发送时间: 2020年8月16日 23:26
收件人: Jeffrey Haas
抄送: rtg-bfd WG
主题: Re: Adoption call for draft-cw-bfd-unaffiliated-echo (ending 16 August, 2020)


Hello Authors,

    I read the document and I do have some questions.


In section 1 text below


"When using BFD echo function, it is not clear whether the devices using echo function need to support the full BFD procotol, including maintaining the state machine of BFD session as described in [RFC5880] and [RFC5881]. According to different understanding, there are two typical scenarios as below:"


I think RFC 5880 section 6.4 "The Echo Function and Asymmetry" clearly calls out BFD echo function is negotiated and also it suggests to keep BFD state machine on both ends with a sedated interval. So not sure why you mention it is not clear in RFC 5880. 

<Weiqiang> This draft would update RFC 5880, in other words, some text in RFC 5880 would not apply to unaffiliated BFD echo function.


Secondly if we do not need BFD async then it need not be BFD echo it can be any packet which is has destination IP set to self IP can do that job isn't it? 

<Weiqiang> In this draft, unaffiliated BFD Echo Function is defined as that the local system needs to support BFD protocol. If both the local system and the neighboring system don't support BFD, then it's outside the scope of this draft.



Santosh P K 





On Tue, Aug 4, 2020 at 6:34 PM Jeffrey Haas <> wrote:

Working Group,

At the virtual IETF 108, Unaffiliated BFD Echo Function was presented.  This
is a followup of a presentation given at IETF 106.

The authors have indicated they would like to have this work adopted by the
BFD WG.  This begins the adoption call ending August 16.  Please respond to
the mailing list with your thoughts on this adoption.

It should be noted that this document overlaps work in the Broadband Forum
(BBF) document TR-146.  As noted in the presentation, the BBF document lacks
some clarity and also doesn't discuss interactions with BFD implementations.
This draft has good clarifications with regard to implementations of this
mechanism when the a BFD Echo-capable implementation is used.

This raises two points to consider as part of adoption:
- This document with its current goals would Update RFC 5880.
- The status of this document would need to be Proposed Standard.

-- Jeff