This counts SCTP associations that ended through the proper graceful SHUTDOWN-SENT/SHUTDOWN-ACK-SENT sequence, representing normal, intended connection teardowns as opposed to the abrupt terminations tracked by cSctpAborteds. Comparing the ratio of this counter to cSctpAborteds over time gives a quick health signal for the SCTP layer on this device: a healthy signaling gateway should show shutdowns dominating aborts by a wide margin. A sudden shift where aborts start outpacing graceful shutdowns is often the first quantitative hint of a developing network or peer problem before individual session failures get reported by users.