MIMIC® IOS Simulator
MIMIC IOS Simulator is a command line simulator that fully supports Cisco IOS® software as well as NX-OS, JUNOS, NETCONF, other command line interfaces and SNMPv1, v2, v2c, v3. You can simulate up to 100,000 devices in a single workstation, and an unlimited number of devices can be simulated by distributing it over multiple workstations. You can access devices using Telnet, SSH and SNMP. Changes made using one protocol is reflected in the other.