This reports the current rate of X.25 calls, in calls per second, being placed through this node. A sudden spike in this rate, distinct from the total concurrent call count, can indicate a call-setup storm, many short-lived calls being placed and torn down rapidly, which stresses the node's call-processing capacity differently than a steady population of long-lived concurrent calls. For example, a spike to 50 calls per second on a node that normally sees 2 calls per second would suggest something is repeatedly dialing and hanging up, worth investigating as a possible misbehaving device.