This is a gauge reporting the highest number of concurrent X.25 calls this node has had in place since its last counter reset. Unlike the current-value counterpart, this peak gauge is what an admin uses for capacity planning over a longer observation window, revealing the worst-case call load the node has actually experienced rather than just a momentary snapshot, useful for deciding whether cdx6500NMNPCmaxCalls needs raising. For example, a peak of 1,490 calls recorded over the past month against a configured maximum of 1,500 would suggest the node is regularly brushing up against its call-admission ceiling and due for capacity review.