Re: [pim] AD Review of draft-ietf-pim-bfd-p2mp-use-case-05

[Alvaro Retana <[e-mail]>]

On August 23, 2021 at 11:34:50 PM, [e-mail] wrote:


Greg:

Hi!

> thank you for your review, comments, and suggestions. I'm working on
> updating the document and preparing the -07 version. I have a question
> related to the scope of the draft. You have identified the essential part of
> the proposal -  a new PIM Hello option to bootstrap a p2mp BFD session.
> Indeed, any PIM  router can use it for advertising its My Discriminator to
> other PIM routers on the shared segment. Then, as I can imagine, depending
> on the role of that PIM router and the configuration on each neighbor, the
> state of the advertising PIM router can be monitored. After detecting the
> failure of the monitored router, we can expect that the monitoring PIM
> router will take the same actions as if the failure was detected according
> to RFC 7761.

Right.


> Thus, it does appear that for all possible uses of p2mp BFD in PIM-SM, all
> that is needed is the new PIM Hello option and reference to the
> corresponding section in RFC 7761.

In general, there's no need to point at specific sections.  In all
cases the BFD timeout indicates a neighbor failure and rfc7761 is
clear about what to do in that case.


> But there might still be value in analyzing each case of using p2mp BFD in
> PIM-SM separately (even as a small informational document), as you've noted
> in:
>
> In the general case... If tracking the sender of a Join, for example,
> the effect would be more significant: an outage would exist until the
> next Join is received.

Honestly, I think that's about the extent of the additional analysis:
a sentence or two.  IOW, I don't think there's value in a separate
document that would just cover that (specially when compared to the
effort of going through the process, etc.).



> Would you agree that the scope of this document includes the definition of
> a new PIM Hello option BFD Discriminator to bootstrap a p2mp BFD session and
> a description of using that option monitoring PIM DR/BDR as a use case
> example?

Well -- that's the point that I've been trying to make: the
applicability is general, the additional considerations (if any) are
minimal, etc..

I would like the scope of this document to be the definition of the
new Hello option + a general description of the applicability to PIM
(all of PIM, not just the DR).   An example is ok.

Just one more thing.  In my comments I keep ignoring the BDR because
the documents that define it are not done yet and I would like to
avoid holding up the publication of this draft.  Note that the general
applicability description (if made general enough) would cover the BDR
function as well -- after all the BDR is also a PIM router that others
can monitor.


If I'm still not being clear, I think we should plan on a f2f
conversation.  Please take a look at my calendar:
https://doodle.com/mm/alvaroretana/book-a-time


Thanks!

Alvaro.