Re: [netmod] YANG coordination feedback on draft-openconfig-netmod-opstate-01

[Martin Bjorklund <[e-mail]>]

Juergen Schoenwaelder <[e-mail]> wrote:
> On Fri, Sep 11, 2015 at 10:54:22AM +0100, Robert Wilton wrote:
> > >
> > >Then Lada brought up the example of ip addresses.  It was mentioned
> > >on the call that for ip addresses there would be three lists; one for
> > >intended, one for applied, and one in derived state, where the one in
> > >derived state is what the box *really* uses.  So for example if it
> > >gets an ip from dhcp, it will be in the derived state list, but not in
> > >applied config.
> > >
> > >Why is this ip-address list different from the interface list?  Why
> > >was it enough with two lists for interfaces, but we need three for ip
> > >addresses?
> > I don't see that they are different.  I think that you have 3 
> > lists/leaves in both cases:
> > 
> > I.e. I would say that 3 IP addr leaves are required in an async system, 
> > at a given time t:
> >  - only the intended leaf can indicate what IP addr config the operator 
> > wants on the interface (if any).
> >  - only the applied leaf can indicate what IP addr is actually being 
> > used as the configured value on the interface.
> >  - only the derived leaf can indicate what IP addr is actually 
> > operationally being used for the interface (which might be due to IP 
> > addr config, DHCP, or perhaps some other mechanism).
> > 
> > I think that in the both kwatsen-netmod-opstate and 
> > wilton-netmod-opstate there are logically 3 interface lists as well:
> >  - /if:interfaces is logically split into 2, either through being 
> > present in separate running and applied datastores, or through having 
> > separate cfg-intended/cfg-applied leaves.
> >  - /if:interfaces-state, which I perceive as logically the derived 
> > state for an interface.
> >
> 
> My personal requirement would be to be able to find all IP addresses
> of an interface that are operationally used in one place.

Yes.  I am trying to understand if a separate list of operationally
used addresses is needed even if we have the "applied config".  I
think the answer is yes.  Then the question is if we don't need a
separate list of operationally used interfaces as well.  If we do,
what value does the "applied config" idea bring us?


/martin