Patent attributes
A network monitoring system maintains both information regarding historical activity of a network, and information regarding emergent activity of the network. Comparison of historical activity of the network with emergent activity of the network allows the system to determine whether network activity is changing over time. The network monitoring system maintains data structures representing a p.d.f. for observable values of network parameters. Recent activity of the network can be compared with both the p.d.f. for historical activity and for emergent activity to aid in determining whether that recent activity is within the realm of normal, and whether network activity is changing over time. The network monitoring system adjusts that information regarding historical activity of a network in response to emergent activity of that network. The network monitoring device determines information regarding time-dependent activity of that network in response to spectral analysis regarding historical activity of that network.