Fully agree with below observation. There was lot of discussion around this when BGP-LS work started on this topic.
The key advantage BGP-LS brings in IGP agnostic transport from any one IGP node (possibly RR) to controller. This was the advantage over “static IGP adjacency/passive peering” with controller (in this case controller has to run IS-IS/OSPFv2/OSPFv3 as opposed to single protocol BGP ==> remember early days ODL has only BGP). But w.r.t real time updates of LSDB to controller nothing can beat passive peering (but this has proximity issue, as controller can be remote). If passive peering with controller can be done on TCP that would have been awesome (can avoid 2 conversions and BGP processing delay of LSDB eventually for PCE). I would also note there are commercial implementations which do innovative passive peering to controller other than TCP (there are no drafts for the same); for folks who care more real time LSDB updates! Yes, this is one side advantage of the proposal being discussed here other than MSDC underlays with crazy number of nodes and massive ECMPs. -- Uma C. From: Lsr [mailto:[email protected]] On Behalf Of Robert Raszuk Sent: Thursday, November 08, 2018 7:36 AM To: [email protected] Cc: Les Ginsberg (ginsberg) <[email protected]>; Tony Li <[email protected]>; [email protected] Subject: Re: [Lsr] IS-IS over TCP All, Again, if people think that LSVR is a good idea, then how can they think that ISIS flooding over TCP is not a good idea ? This is the base idea for our proposal. A quick look at the LSVR draft show people from Cisco, Nokia (and Arrcus). (I'm not sure what Juniper or Arista or other vendors think about using BGP-LS). I would like to make one additional observation here ... We are experiencing BGP-LS crusade (completely outside of LSVR) as there is some demand to send data carried by IGP (incl SR, TE and now even BFD extensions) to remote controllers over TCP. I am pretty sure that BGP-LS would have never started if we would have had an ability to send LSDB content over TCP day one. /* Let's put controller to controller NNI across ASes aside for a moment. */ With that to me ability to progress with TCP transport extension for ISIS (and OSPF) is actually more important then work on flooding reduction. I know it may not be a popular statement, but that is based on both looking at the operational side as well as BGP protocol side. Thx, R.
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