The Orion VoIP monitor is considered an active monitoring solution in that it uses Cisco IP SLA to generate synthentic VoIP traffic. There are other VoIP monitoring solutions out there that use a Passive approach in that they sniff actual VoIP traffic to see how real user calls are performing.
I would like to know your thoughts on these two approaches to monitoring VoIP? Should we look to deploy a VoIP monitoring solution that encompasses both active and passive monitoring?