There is a special kind of fear known only to network managers. It starts with a cold, dull ache in the pit of the stomach when the phone rings and a distant, irate voice whines, "The network is slow." The complaint is not the problem; the problem is the realization that despite state-of-the-art switching and idling servers, the network is slow and you don't know any more than the tiny voice pressed to your skull. That's when it's time to consider application performance monitoring tools.

There is a clear distinction between application monitoring and