Defines the traffic priority level of all the incoming packets
on this port.
CNGC_PRIORITY_TWO - Default value
Set all incoming user traffic packets to priority 2.
CNGC_PRIORITY_ONE - Set all incoming packets to priority 1.
CNGC_PRIORITY_TWO - Set all incoming packets to priority 2.
CNGC_PRIORITY_THREE - Set all incoming packets to priority 3.
Priority 0 is reserved for network critical packets like
OSPF, FR LMI and SMDS heartbeat, Cross Net polling and is
not available for user traffic.