All of the resources we have considered so far have been dimensioned on a discrete
basis where one customer requires one interface and one port, and one card requires
one slot. Each step reflects the physical path into the network, but the requirement
is logical, in the sense that a customer is either connected, or not; there are
no partial connections.
The Uplink is different, because the requirement
is a function of how much a customer uses the network, which is also likely to vary
over time.