________________________________________
From: Andy Bierman <[email protected]>
Sent: 08 December 2021 17:58
On Wed, Dec 8, 2021 at 9:27 AM tom petch
<[email protected]<mailto:[email protected]>> wrote:
From: Ladislav Lhotka <[email protected]<mailto:[email protected]>>
Sent: 08 December 2021 12:38
tom petch <[email protected]<mailto:[email protected]>> writes:
> The BFD WG are revising RFC9127 to add a new feature if-feature
> "client-base-cfg-parms"; and make uses base-cfg-parms { conditional
> thereon in module ietf-bfd-types. Reading and re-reading RFC7950,
> especially about mandatory and top-level, I am not convinced that
> this is legal.
Sorry, I don't get the problem - nothing in the "base-cfg-parms" grouping is
mandatory. Why do you think this might be illegal?
<tp>
Reading that section I find parts less than clear, especially about top level
and mandatory. Could a PIM eg module importing that grouping make it top level
or mandatory even if it is not so in the BFD module?
Yes. The refine-stmt can add or change a mandatory-stmt.
https://datatracker.ietf.org/doc/html/rfc7950#section-7.13.2
This only affects the specific "uses" of the grouping, never the grouping
itself.
<tp>
Andy, Lada,
Thanks for the responses. Perhaps I should stop worrying. None of the
importing modules - PIM, OSPF. BGP, RIP - use refines for bfd-types but even if
they did, then the conditional in new bfd-types would still be valid.
Tom Petch
Andy
I realise that such as NACM can always make part of the tree invisible so
software has to be prepared for something to be missing but I am not confident
of my interpretation.
Tom Petch
Lada
> The module bfd-types is imported by a number of other modules such
> as OSPF, RIP, PIM so it is also a question if e.g. a leaf can be
> made mandatory by its usage in another module. I raised this on the
> BFD list and the WG Chair tells me that this is a violation of the
> intent of the RFC, 7950, but that it has been reviewed by YANG
> doctors and is probably the best fix.
>
> If YANG Doctors collectively say that this violation is ok, then I think that
> such a statement needs to appear on the Netmod WG list.
>
> I think that there are a lot of other editorial changes needed to 9127-bis to
> make it legal but they can come later. The I-D is in WG Last Call ending
> 20Dec2021
>
> Tom Petch
> _______________________________________________
> netmod mailing list
> [email protected]<mailto:[email protected]>
> https://www.ietf.org/mailman/listinfo/netmod
--
Ladislav Lhotka
Head, CZ.NIC Labs
PGP Key ID: 0xB8F92B08A9F76C67
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