Inter-AS Metric Selector. This parameter indicates
whether or not an INTER_AS_METRIC will be advertised
for a network matching this filter and, if advertised,
what value to use. 'none' indicates that no metric will
be advertised. 'specified' indicates that the value in
wfIpBgp3AnnounceInterAsMetric will be used. 'originating'
indicates that the metric from the originating
protocol will be used. Only valid if 'action' is
'announce'.