The value of tRPAdminPSDefActionMetricSource specifies the source
of the default action metric.
When the value of tRPAdminPSDefActionMetricSource is set to
'igpCost(1)', the value of tRPAdminPSDefaultActionMetricValue is
ignored and the value of MED (Multi Exit Discriminator) or the metric
value is derived from the IGP (Interior Gateway Protocol) cost of the
route.
The default value of tRPAdminPSDefActionMetricSource is
'metricVal(2)' which means the metric value is the value of
tRPAdminPSDefaultActionMetricValue.