This read-write object sets the high memory watermark for the PNNI task; if memory allocated to PNNI exceeds this value, the node enters a topology database overload state. An admin tunes this to protect the switch from running out of memory due to an oversized PNNI topology database, at the cost of entering a degraded overload state when exceeded. Setting it to a lower value would make the node more conservative, entering overload state sooner as PNNI memory usage grows.