The market for testing Diameter based devices develops quickly. Few days ago I mentioned a new product from Mobile Metrics (here) but they are not alone out there.
Developing Solutions announced in October that a "Leading wireless operator selects Developing Solutions’ dsTest platform to verify performance of their Policy and Charging Rules Function (PCRF) and Diameter Routing Agent (DRA) .. The dsTest platform can simulate real-world load scenarios for the PCRF and DRA in order to verify both the functional requirements and operational load. A single dsTest server can scale up to support more than 5,000 emulated nodes, hundreds of thousands of transactions per second, and more than 50 million simulated subscribers".
Not so many North American MNOs have more than 50M subscribers, a PCRF and a Diameter Router systems installed. Learning from Verizon's recent experience (outage due to some IMS components), comprehensive testing may help preventing it from happening again.