Some IDSs coordinate input from multiple sensors into a single reporting console, which lets you receive notification of illicit traffic from anywhere within the network. However, multiple monitoring locations means more data to store, examine and act upon.
Automated tools for analyzing IDS logs are available, but most interpretation is done by an IT person who's trained in what to look for and knows your traffic patterns. He or she combs through the IDS log to see how a perpetrator got past your security systems.
A successful IDS deployment doesn't need heavy CPU horsepower. It does, however, need to be connected to the network properly and have enough storage to allow useful analysis of the data (see "Step by Step,").
You can install the IDS via a span port on a switch, for example, or via a network tap. Each method has its advantages and disadvantages.