Naiming –

Inline…

From: Naiming Shen (naiming)
Sent: Sunday, October 21, 2018 3:12 PM
To: Les Ginsberg (ginsberg) <ginsb...@cisco.com>
Cc: Reshad Rahman (rrahman) <rrah...@cisco.com>; rtg-bfd@ietf.org
Subject: Re: BFD WG adoption for draft-haas-bfd-large-packets


It probably should say “the payload size MAY be increased to this value and it 
is
not recommended for a BFD session to always use the large size packet for 
padding.
How frequent the large size packet being used is application specific”.

[Les:] This does not address the question as to why we want to use a mechanism 
specifically designed for sub-second detection for this case.
??? (Note that it does not come for free. ☺ )

for the variety of encaps, the internal application probably can deduced from a
BFD one into their own as long as we have a number for path MTU.

[Les:] If “your” MTU requirements are smaller than “mine” – would you want the 
BFD session to go down even though you could continue to use the link 
successfully?

   Les

thanks.
- Naiming

On Oct 20, 2018, at 5:14 PM, Les Ginsberg (ginsberg) 
<ginsb...@cisco.com<mailto:ginsb...@cisco.com>> wrote:

I have some concerns.

It has been stated that there is a need for sub-second detection of this 
condition – but I really question that requirement.
What I would expect is that MTU changes only occur as a result of some 
maintenance operation (configuration change, link addition/bringup, insertion 
of a new box in the physical path etc.). The idea of using a mechanism which is 
specifically tailored for sub-second detection to monitor something that is 
only going to change occasionally seems inappropriate. It makes me think that 
other mechanisms (some form of OAM, enhancements to routing protocols to do 
what IS-IS already does ☺) could be more appropriate and would still meet the 
operational requirements.

I have listened to the Montreal recording – and I know there was discussion 
related to these issues (not sending padded packets all the time, use of BFD 
echo, etc.) – but I would be interested in more discussion of the need for 
sub-second detection.

Also, given that a path might be used with a variety of encapsulations, how do 
you see such a mechanism being used when multiple BFD clients share the same 
BFD session and their MTU constraints are different?

Thanx.

   Les


From: Rtg-bfd <rtg-bfd-boun...@ietf.org<mailto:rtg-bfd-boun...@ietf.org>> On 
Behalf Of Reshad Rahman (rrahman)
Sent: Wednesday, October 17, 2018 6:06 PM
To: rtg-bfd@ietf.org<mailto:rtg-bfd@ietf.org>
Subject: BFD WG adoption for draft-haas-bfd-large-packets

Hello BFD WG,

We have received an adoption request for “BFD encapsulated in large packets”.

https://datatracker.ietf.org/doc/draft-haas-bfd-large-packets/

The adoption call will end on Friday Nov 9th.

Please send email to the list indicating “yes/support”  or “no/do not support”. 
If you do not support adoption, please state your reasons.

Regards,
Reshad & Jeff.

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