Hello Scott,

  I added the words “to provide hysteresis” at the end of the sentence. Please 
let me know if this helps. Please suggest alternate text if you think this can 
be improved upon.

Thanks
Prasad



The BFD session MAY be removed in the egress LSR if the BFD

session transitions from UP to DOWN.  This can either be done

immediately after the BFD session transitions from UP to DOWN

 or after the  expiry of a configurable timer started after the BFD

 session state  transitions from UP to DOWN at the egress LSR

to provide hysteresis.





-----Original Message-----
From: Bradner, Scott [mailto:[email protected]]
Sent: Tuesday, October 13, 2015 3:00 PM
To: Vengada Prasad Govindan (venggovi) <[email protected]>
Cc: [email protected]; [email protected]; 
[email protected]; Jeffrey Haas <[email protected]> ([email protected]) 
<[email protected]>
Subject: Re: ops-dir review of draft-ietf-bfd-rfc5884-clarifications



the addition i good but it still does not say what the purpose is for using a 
timer  - the “why” - you have the “how”



Scott



> On Oct 13, 2015, at 12:29 AM, Vengada Prasad Govindan (venggovi) 
> <[email protected]<mailto:[email protected]>> wrote:

>

> Hello Scott/ all,

> Thanks for your comment, do you think the proposed text below makes better 
> sense (additions highlighted in green):

>

>       The BFD session MAY be removed in the egress LSR if the BFD

>       session transitions from UP to DOWN.  This can either be done

>       immediately after the BFD session transitions from UP to DOWN

>      or after the  expiry of a configurable timer started after the BFD

>     session state  transitions from UP to DOWN at the egress LSR.

> I can post a new revision reflecting this comment if you are fine with the 
> proposed text.

> Thanks

> Prasad

>

> -----Original Message-----

> From: Bradner, Scott [mailto:[email protected]]

> Sent: Monday, October 12, 2015 7:39 PM

> To: [email protected]<mailto:[email protected]>; 
> [email protected]<mailto:[email protected]>

> Subject: ops-dir review of draft-ietf-bfd-rfc5884-clarifications

>

> I have done a OPS-DIR review of "Clarifications to RFC 5884” 
> <draft-ietf-bfd-rfc5884-clarifications-03.txt>

>

> summary - ready for publication

>

> This document clarifies how best to operate multiple BFD (Bidirectional 
> Forwarding Detection) sessions in MPLS environments.

> Any document that purports to clarify operational procedures is, by 
> definition, a good thing when it comes to operational impact, assuming the 
> document is clear and makes sense.  This document is clear and makes sense.

>

> One suggestion though.

> The first observation in Section 2.3 says:

>

>       The BFD session MAY be removed in the egress LSR if the BFD

>       session transitions from UP to DOWN.  This can be done after the

>       expiry of a configurable timer started after the BFD session state

>       transitions from UP to DOWN at the egress LSR.

>

> It might be helpful to specifically say what the aim of using such a timer 
> is.  My guess is that the timer is used to introduce hysteresis to reduce 
> flapping - but it would nice to say one way or the other

>

> Scott


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