This Counter32 reports the current number of AH-encrypted inbound 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 AH inbound 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 AH inbound SAs on VI 5 on an inter-region backbone tunnel but sees this counter reading only two would know some subnet pairs failed to negotiate AH setup.