This read-only Integer32 object is the interface index identifying which interface a row of the zxrosAMATInterfaceStatisticTable's inbound and outbound filtered-packet counters applies to. Admins use it to match the AMAT packet-drop counters back to the specific interface they were measured on when reviewing filtering statistics across the device. For example, this field would read the same interface index as the corresponding row in zxrosAMATInterfaceEnableTable, letting an admin cross-reference whether AMAT is enabled and how many packets it has filtered on that interface.