Introduction

At this point, we have examined and hardened the working components of the existing security infrastructure, established procedures to confirm user and device identities, and logically separated voice and data traffic, thus allowing the network to now carry them. The next step in maintaining the security of this infrastructure is to monitor traffic and the state of key devices. This is accomplished by active monitoring.

Plenty of commercial and open-source tools exist to help with this, and in this chapter we will look at several categories of them. We won t, however, discuss in any detail the large commercial network monitoring suites like NetIQ, SMARTS, BMC Patrol, HP OpenView Operations, HP Network Node Manager NNM, IBM Tivoli, Nortel Optivity NMS, Cisco Ciscoworks, Sun Solstice SunNet Enterprise Manager, Micromuse, Computer Associates CA Unicenter, and Microsoft Operations Manager 2000 (MOM). While we recommend that organizations employ one or more of these enterprise tool suites (particularly to monitor network jitter, packet loss, and latency), the configuration, use, or integration of any one of these tool suites with VoIP network monitoring components is complex, dependent upon both the suite chosen for monitoring, and the peculiarities of each particular network. For these reason we will have to leave this discussion to another time.

A related class of tools for both monitoring and performance testing of VoIP networks include tools like Empirix Hammer, Brix Network Verifier, and Shunra s Virtual Enterprise. These tools use different techniques and metrics to monitor the functionality, performance, scalability, and robustness of...