NML currently defines "resource labels" as defined in section 6.7.1.1 of ITU-T G.800. This is useful for circuit based 
technologies, such as DWDM and Ethernet VLANs.

IP and Ethernet MAC don't use resource labels, but instead use source labels and destination labels.

Freek proposes to distinguish between resource labels and source/destination labels in NML too, to allow IP descriptions
.