Capacity Verification for High Speed Network Intrusion Detection Systems

Abstract

Commercially available Network Intrusion Detection Systems (NIDS) came onto the market over six years ago. These systems have gained acceptance as a viable means of monitoring the security of consumer networks, yet no commercial standards exist to help consumers understand the capacity characteristics of these devices. Existing NIDS tests are flawed. These tests resemble the same tests used with other networking equipment, such as switches and routers. However, switches and routers do not conduct the same level of deep packet inspection, nor require the higher-level protocol awareness that a NIDS demands. Therefore, the current testing does not allow consumers to infer any expected performance in their environment. Designing a new set of tests that is specific to the weak areas, or bottlenecks, of a NIDS is the key to discovering metrics meaningful to the consumers. Any consumer of NIDS technology can then examine the metrics used in the tests and profile his network traffic to these same metrics. The consumer can use standard test results to accurately predict performance on his network. This paper proposes a test methodology for standardized capacity benchmarking of NIDS. The test methodology starts with examining the bottlenecks in a NIDS, mapping these bottlenecks to metrics that can be tested, and then exploring some results from tests conducted.