The functional capability of the port.
This allows the Manager code to determine the
capabilities of the port so the proper
data can be managed based on the functions
the WAN port can provide.
A 'frameType' port supports layer 2 protocols such
as HDLC and Frame Relay.
A 'cellType' performs ATM interface functions such
as ATM T1 UNI interface.
A 'cbrType' port is used to perform Bit to Cell Conversion
(AAL1).