Re: [Lsr] Moving Forward [Re: Flooding Reduction Draft Redux]

["Les Ginsberg (ginsberg)" <[e-mail]>]

Robert –

Let’s please not introduce issues which are not relevant. ☺

Any flooding optimization solution only applies to a single LSDB – and the set of nodes/links which support flooding of that LSDB. This means (in IS-IS speak):


·         Level-1 is distinct from Level-2. I could choose to apply flooding optimizations to one level and not the other if I wished. Or use a different algorithm/level

·         One MI instance is distinct from another

·         MT is not relevant since all the MT specific advertisements for all supported topologies are contained within a single LSDB (I.e., we do not support MT specific flooding)

HTH

   Les


From: Lsr <[e-mail]> On Behalf Of Robert Raszuk
Sent: Sunday, February 03, 2019 12:37 PM
To: Tony Li <[e-mail]>
Cc: Huaimo Chen <[e-mail]>; [e-mail]; David Allan I <[e-mail]>; [e-mail]; [e-mail]
Subject: Re: [Lsr] Moving Forward [Re: Flooding Reduction Draft Redux]


I fully agree and support proceeding with  draft-li-dyanmic-flooding and to include protocol extensions in it for centralized topology propagation as well as basic hooks like "execute dynamic protocol number X" for distributed calculations.

However one may observe that separate distributed algorithms may define their own protocol extensions and they should not break the above in any way.

Then there is already some requirements of building two disjoined topologies in any rich ECMP DC fabric one say for primary paths the other for backup flows. (Case of active-active dual streaming applications). Question arises if this would be addressed also as part of basic spec, be combined with one or many of distributed algorithms or will require yet one more document which in turn will "extend" all of the above ? And before anyone suggests multi instance approach with logical or physical link separation it is not the right direction here. If anything perhaps MTR or SR come a bit closer.

Kind regards,
Robert.


On Sun, Feb 3, 2019 at 9:14 PM <[e-mail]<mailto:[e-mail]>> wrote:

I think that this discussion would be greatly clarified if we clearly separated the discussion between

a) the algorithm for computing the flooding topology, and
b) the signaling to indicate how to proceed.

I think that we are all in agreement that the algorithms can and should be separated from the signaling.

I think that we are all in agreement that each algorithm should be independent.

I’m of the opinion that the centralized signaling is a bit more extensive than the signaling for the distributed mode, but that there is also considerable overlap and that things would
be unnecessarily redundant if we were to separate them. I believe that we are not in disagreement about the basics for the distributed signaling.

If you disagree with this, please clearly articulate why you feel the signaling should be separated.

Regards,
Tony