How is realistic MQTT testing with MIMIC different from simplistic testing?

Most simple test apps use a for loop to create connections to a MQTT broker,
using only one single IP address for a large number of client sessions.

By using one IP address per session with MIMIC MQTT Simulator just like in

real world scenarios (when do real sensors share IP addresses?) we
uncovered a flaw in third-party MQTT brokers.

They would fail after a small number of simulated sensors (typically 1000
connections).

Only after adjusting the ARP cache parameters on the broker systems did
we overcome this problem.

MIMIC allows you to create realistic IoT pre-deployment testing scenarios
using IPv4 or IPv6 addressing, just like in the real world.