[Nml-wg] hasService / hasInboundPort

[Freek Dijkstra]

On 12-03-2013 15:50, Jeroen van der Ham wrote:

> For most of the NML model we have made it so that there is only one
> relation defined between two objects. However, Richard spotted a
> situation where we do have two:
> 
> - A Port can have a "hasService" relation to a SwitchingService
> - A SwitchingService can have a "hasInboundPort" relation to a Port
> 
> Perhaps it would make sense to suggest a preference that one of them
> must be there and that the other is optional. The second relation is
> slightly more informative, so that is probably better.

Very good catch by Richard.

The second is more than "slightly" more informative; I'd even dare to
say it contains vital additional information about the direction.

So I suggest we should make the second form a MUST, and the first a
SHOULD NOT. (Admittedly, the first form does no harm at all, and is
useful. The reason for the strong SHOULD NOT is that it brings a risk of
incompatibility if one organisation uses the first form, and another
organisation uses the second form)

Freek