RE: WG last call for draft-ietf-rtgwg-spf-uloop-pb-statement

[Uma Chunduri <[e-mail]>]

Hi Chris and Co-authors,

Something to this spirit before the last bullet point in Section 2.

   o   SPF computation order:  A SPF trigger can be common to  multiple IGP areas or levels (e.g., IS-IS Level1/Level2) or 
        for multiple address families with multi-topologies. There is no specified order for SPF computation today and 
        it is implementation dependent. In such scenarios, if the order of SPF computation done
        in A and B for each area/level/topology/SPF-algorithm is different, there is a 
        possibility for a micro-loop to appear.  
        
BR,
--
Uma C.


-----Original Message-----
From: Chris Bowers [mailto:[e-mail]] 
Sent: Tuesday, January 16, 2018 1:49 PM
To: Uma Chunduri <[e-mail]>
Cc: RTGWG <[e-mail]>; rtgwg-chairs <[e-mail]>
Subject: Re: WG last call for draft-ietf-rtgwg-spf-uloop-pb-statement

Uma,

Could you propose some specific text to add to the document to address your comment?

Thanks,
Chris

On Wed, Dec 6, 2017 at 1:54 PM, Uma Chunduri <[e-mail]> wrote:
> Support and have a following comment and want to see this addressed.
>
>
>
> Section 2:
>
>
>
>  I saw SPF computation time has been discussed, while it is true this 
> is relatively a smaller issue when compared to mismatch in SPF delay 
> with different trigger algos across various vendors; it depends on the 
> size of the network + mix of legacy and new nodes.
>
>  Any ways, my comment:
>
>   I would like to see add one more bullet point with regard to SPF 
> computation order impact on the micro loops  for a trigger i.e., a 
> trigger which is common to multiple levels/areas, multiple topologies 
> and multiple SPF-algorithms (in extreme case).
>
>  There is no specified order today and its implementation dependent 
> and IMO this too would be a significant contributor (of course, not 
> asking to specify the order here) and visible once the SPF 
> delay/trigger-algo issue is fixed across. So this is worth being listed here.
>
>
>
>
>
> --
>
> Uma C.
>
>
>
> From: rtgwg [mailto:[e-mail]] On Behalf Of Chris Bowers
> Sent: Wednesday, December 06, 2017 11:19 AM
> To: RTGWG <[e-mail]>
> Cc: rtgwg-chairs <[e-mail]>
> Subject: WG last call for draft-ietf-rtgwg-spf-uloop-pb-statement
>
>
>
> RTGWG,
>
> This email starts the two week WG last call for 
> draft-ietf-rtgwg-spf-uloop-pb-statement.
>
> https://datatracker.ietf.org/doc/draft-ietf-rtgwg-spf-uloop-pb-stateme
> nt/
>
>
> Please indicate support for or opposition to the publication of this
>
> informational document, along with the reasoning behind that support 
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> opposition.
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> IPR:
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> This last call will end on Thursday, December 21st.
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> Thanks,
>
> Chris and Jeff