Subject: [netmod] Question regarding YANG model revision (in context of submodules)

From: "Bogaert, Bart (Nokia - BE/Antwerp)" <[email-masked]>
Date: Thu, 14 Dec 2017 13:56:11 +0000

Hi,

I've been looking in various documents w.r.t. the usage of a model revision
statement, especially in the case where the YANG model is split up in
various submodules.

Assume that one of the included submodules is changed and gets a new
revision while the model this submodule belongs-to is not updated.  How is a
client supposed to know that there was a change?

The YANG library does include a list of submodules for each YANG model but
is it expected to scan that list?  What in case there is no YANG library
(this is only mandatory in the case of YANG 1.1)?  In the hello, only the
revision of the YANG model is announced, so in that case no change would be
visible although there is one.

Is there some explicit statement in RFC 7950 or 6087bis on this (meaning
that if a submodule gets a new revision, the revision of the owning YANG
model must also be updated)?  There are statements that imply that this
could be done (e.g. by specifying the revision-data when doing the include
but if no revision data is specified the behavior is "undefined" meaning
that the version of the submodule that is stored on the server will be used
but still leaves room for uncertainty).

Regards, Bart