This attribute specifies the discard priority for outgoing call using
this DLCI.
The discard priority has three provisioning values: normal, high,
and useDnaDefPriority. Under congestion conditions, traffic with
normal priority is discarded before traffic with high priority. The
Dna default value (provisioned by outDefaultPriority) is taken if
this attribute is set to the value useDnaDefPriority.