Aaron Brown wrote:
A _Port_ is related to zero or one _Node_, and also has a relation with zero, one or two (uni-directional) _Links_. Where does an unconnected port exist?
When we define an inter-domain link we typically define a connection to an unconnected port and point to the other domain for more information about that interface. But I guess this is also a remnant of us preferring to use a relation between interfaces, instead of a link object in between. So I guess we could also require that an interface is connected to a node. What does the rest think?
* A _Port_ MAY have a _source_ relation with up to two _Unidirectional Links_. * A _Port_ MAY have a _sink_ relation with up to two _Unidirectional Links_. Does this mean that a port might be a sink for two unidirectional links? If so, under what circumstances could it occur that a port could be a sink for more than one link, but not more than two?
A Port typically has two uni-directional links to another device, and two uni-directional crossconnects (crossconnects are also links). So then it has two source relations and two sink relations. Freek also brought up an example where a SONET switch with an Ethernet interface. If you just look at the Ethernet Layer, this would appear as a Port with links ("actual link links") to two devices. Jeroen.