This Counter32 reports the current number of ESP-encrypted outbound SAs currently active for this Virtual Interface, per its description, a live gauge rather than a lifetime running total. An admin watches this to see right now how many ESP outbound security associations are actually up on the tunnel, useful for confirming a tunnel carrying multiple SAs (e.g. per-subnet) is fully established rather than partially negotiated. For example, an admin who expects four ESP outbound SAs on VI 11 on a redundant backup tunnel path but sees this counter reading only two would know some subnet pairs failed to negotiate ESP setup.