This read-write value sets the maximum depth, in bytes, that the ingress queue may reach before the card begins dropping arriving cells, with most cards limited to a range up to 'ffff'h while FRSM-VHS supports depths up to '1fffff'h, and the object is not supported at all on FRSM12. An administrator must configure this value greater than both ingressQECNThresh and ingressQDEThresh so that ECN marking and DE (Discard Eligible) marking can take effect before the queue's hard drop limit is reached. For example, setting ingressQDepth too close to ingressQECNThresh would leave little room for early congestion notification to have any effect before outright cell dropping begins.