The desc explicitly states this is the count of IPsec AH encrypted packets, the packet-level mirror of the AH SA counters elsewhere in this MIB. Like the AH SA counters, this stays at zero on the vast majority of modern deployments that use ESP exclusively, so its main value is as a tripwire — any nonzero reading confirms AH traffic is actually being sent, not just that an AH SA merely exists in the configuration. e.g. remains at 0 for a typical ESP-only gateway's entire uptime.