lr-wpan: Treatment of constants as variables (RFC)

In a recent merge #823 (closed), it was decided to group all the PHY and MAC constants in a single lr-wpan-constants.h file where upper layers are able to see and make use of these constants. This is all relatively good. However, we skipped one important point. In a real hardware implementation, these constants exist on a device-per-device basis. Meaning that different devices _ can have _ different constant values because they have different capabilities (for instance when comparing a coordinator device and an end device).

In most cases, constants tend to use the same values among devices. However, there are some cases when is desirable to give different constant values to some devices in the network. For example constants like:

aUnitBackoffPeriod, aMaxLostBeacons, to mention a few.

Naturally, in the current ns-3 implementation, it is not possible to do this and assign different constant values to devices. This takes me to the title of this issue, shouldn't these standard-defined constants be treated as variables instead to allow this flexibility?

I ask this question because I have a similar issue in the current zigbee NWK layer development.

I would like to hear your opinions.

Regards,

Al.