[Nml-wg] Versioning

[Jason Zurawski]

Hi Freek/All;

As in my response on your/Jerry's other proposals, some example are 
required to highlight the positive and negative aspects of each approach 
to accurately gauge the argument why there needs to be a change.

Thanks;

-jason

On 3/4/12 8:14 AM, thus spake Freek Dijkstra:
> Each NML object has a "Lifetime" attribute which specifies -well- when
> an NML object is valid.
>
> I see two problem with that, namely that it is often not known in
> advance when the lifetime of an object terminate, and that describing
> the lifetime of each object is not very efficient.
>
> Jerry's idea about versioning and topology updates made me reconsider
> the current proposal.
>
> Jerry's idea is to simply change a whole topology description (or
> subtopology description) when it is changed. This seems more useful than
> to change the lifetime of each individual network object.
>
> Hence I propose to get rid of the Lifetime object and replace it with a
> version attribute, which is a timestamp.
>
> The version attribute should be used for topologies (or for any network
> object if the WG prefers). The meaning of the version attribute is that
> the topology with the latest timestamp (before now -- see below)
> describes the current active topology. This is much like the version
> string in DNS SOA records. A topology can be end-of-life'd by describing
> the topology without any ingress or egress Ports, and giving it a new
> timestamp.
>
> One of the great features of the "Lifetime" attribute is that it would
> allow description of future topologies, and hence advance reservations.
> This is why the "before now" in the above description comes in. It would
> allow one to describe a topology with a timestamp that lies in the
> future. The meaning would be that that topology would not be valid until
> that time is reached, hence allowing the description of future
> topologies as well.
>
> This seems much easier than the current proposal, and just as flexible.
>
> Can we decide to replace Lifetime with version?
>
> Regards,
> Freek