This INTEGER (allow/deny) is a coarse per-sub-port traffic gate; setting it to deny effectively blocks all traffic on that sub-port regardless of any other QoS or forwarding configuration applied to it. It is a blunt but immediate tool for administratively shutting down a specific customer's service, for example for non-payment, without deleting their configuration. Flipping this to deny to immediately suspend a customer's service while preserving all their other sub-port settings for quick reactivation later is a common operational use.