Re: [i2rs] comments on draft-ietf-i2rs-ephemeral-state-10

[Juergen Schoenwaelder <[e-mail]>]

On Thu, Jun 23, 2016 at 03:12:50PM +0100, Robert Wilton wrote:
> Hi,
> 
> On 23/06/2016 13:02, Juergen Schoenwaelder wrote:
> > Hi,
> > 
> > here are few comments on the latest version.
> > 
> >     Ephemeral-REQ-03: Ephemeral state must be able to utilized temporary
> >     operational state (e.g.  MPLS LSP-ID or a BGP IN-RIB) as a
> >     constraints.
> > 
> > I am not sure what 'must be able to utilized temporary operational
> > state as constraints' means. The text in the parenthesis does not help
> > me understand this better. Did you want to say something like:
> > 'Ephemeral configuration state may have constraints that refer to
> > operational state'? I am using 'ephemeral configuration state' since
> > this is used in other places (although sometimes worded slightly
> > different).
> I asked a similar question in the I2RS  interim meeting yesterday, I think
> that Sue's spoken explanation of the requirement was effectively:
> 
>    Ephemeral-REQ-03: Ephemeral state may have constraints that refer
>    to operational state, this includes potentially fast changing or
>    short lived operational state nodes, such as MPLS LSP-ID or a BGP IN-RIB.
> 
> Perhaps this wording is more clear?

Yes, this is clearer. One question of course is what is expected to
happen if constraints are becoming false due to (fast) operational
state changes, that is, what the expected consequence of this is.

> >     Ephemeral-REQ-04: Ephemeral state MAY refer to non-ephemeral state
> >     for purposes of implementing constraints.
> > 
> > Hm, now I wonder whether this is just a special case of
> > Ephemeral-REQ-03 and if so it is not clear why we need this as a
> > separate requirement. If this is not the case but something different,
> > then likely my interpretation of Ephemeral-REQ-03 is wrong.
> I think that ephemeral state could also use configuration nodes as a
> constraint, so it isn't just operational state covered by REQ-3.

Well, the Ephemeral-REQ-04 text says 'non-ephemeral state' - if your
interpretation is correct than this phrase is wrong or possibly
misleading.

/js

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