This object restricts the scope of the filter to calls which
exited the ATM device through the port represented by this object
It has the value 0, or the ifIndex value of an ATM Interface.
The value zero indicates that the scope of the filter is not
restricted by the outgoing port. To track calls failed locally
in the ATM device in which the call failure tracking is in
progress ,the csfFilterScope object should be used , in which
case the value of this object need not be changed from its
default value.