This attribute specifies the time period used in seconds, to age out
dynamically learned entries in the forwarding table. The aging time is
specific to a spanning tree protocol instance running. A value for the
aging time of the current instance of the spanning tree protocol can be
provisioned through the attribute agingTime under the InwBrTb
component. The agingTimeOper attribute assumes the value of the
bridgeForwardDelay while a topology change is in progress. This is
done to facilitate quick aging out of the learned entries that might have
become obsolete due to a spanning tree topology change.