Re: [netmod] Inventory YANG model (entity-MIB)

[Juergen Schoenwaelder <[e-mail]>]

On Fri, Mar 06, 2015 at 11:48:02AM +0100, Benoit Claise wrote:
> Dear all,
> 
> The I2RS interim meeting yesterday focused on topology.
> Let me cut/paste a high level slide, with pointers to the relevant drafts.
> 
> 
> If interested, the meeting minutes are at 
> http://etherpad.tools.ietf.org:9000/p/i2rs-interim-march-5-2015-v-bluesheets
> 
> Part of the inventory draft 
> (http://datatracker.ietf.org/doc/draft-dong-i2rs-network-inventory/) 
> discussion, the overlap with the ENTITY-MIB RFC 6933 was discussed (and 
> RFC 7223 btw).
> 
> 
> The message was that I2RS should not re-invent something similar to the 
> ENTITY-MIB
> So, are you aware of any initiatives to "YANGify" the ENTITY-MIB?
> It's true that there is a way to translate MIB into YANG with RFC 6643. 
> This could be a good start. However, I wonder if a hand-written YANG 
> model that closely follows the entPhysical would not be more beneficial.
> Is this something we should take on board in NETMOD?
> 
> What do you think?
> 
> Note: As commented by the I2RS people, indexing is appropriate in the 
> MIB module for its original purpose, but may not be for the topology. 
> I'm not sure we want to change the indexing just for the topology, but 
> the integration within the topology draft should be thought of.
>

My first question is (perhaps not surprising) whether inventory falls
into the I2RS charter, I2RS = interface to the routing system. That
said, RFC 6643 gives you a read-only translation. There are not many
read-write objects in the ENTITY-MIB so perhaps this is good enough
for now. I guess it would help what I2RS needs to know in order to
make the interface to the routing system work.

Anyway, if YANG models overlapping the ENTITY-MIB are done, they they
should at least allow implementation of both in a predictable manner.
Looking at draft-dong-i2rs-network-inventory-00, it seems the whole
interface list is already covered by RFC 7223 and interfaces should be
references not repeated (this is what the ENTITY-MIB does). So what is
left is essentially a (not yet hierarchy) of 'cards' that seem to more
or less match the entPhysicalTable of the ENTITY-MIB (but then the
ENTITY-MIB has a more flexible model that distinguishes between
different kind of hardware components). I also notice that the model
in draft-dong-i2rs-network-inventory-00 is config true - so I am not
sure how this is supposed to use. Is the idea that this model is an
interface to an inventory database where I configure what I have
instead of a model sitting on a device where I can query what the
device actually has?

/js

PS: I personally would have preferred if generic topology and perhaps
    inventory would have split off into a short-lived targeted WG
    instead of doing all of this in I2RS but it seems leadership has
    already decided that I2RS is the home for all of this.

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
Fax:   [phone]         <http://www.jacobs-university.de/>