Vistara is a multi-tenant SaaS based product that serves thousands of customers, managing a large number of devices. Vistara runs on a highly scalable Big Data platform that processes over a billion data samples per day. Vistara is architected to be scaled out on demand. To ensure that Vistara can meet real-time performance demands, the product is tested thoroughly under variety of conditions and against a wide range of devices. Specific features, like Vistara’s performance data visualization, also require in-depth testing. Vistara’s QA team previously used only physical devices in their lab for testing. With this approach, it was very difficult to test product behavior under extreme load scenarios across devices from many different vendors. To address this need, Vistara decided to augment their lab with a network simulator. Vistara needed an enterprise grade network simulator that can simulate SNMP agent behavior as well as various console protocols such SSH/Telnet in depth. They also needed a tool that came with a large library of pre-defined networks that they could use as simulated test devices. Vistara evaluated the market for an enterprise grade network simulator. MIMIC SNMP and Telnet/SSH Simulator stood out in meeting all of its requirements.