When Christophe Fillot began emulating Cisco routers with Dynamips, each instance of a simulated router required its own instance of Dynamips, along with a string of command line options to specify, for example, the amount of RAM, the interfaces, and the virtual connections to other instances of Dynamips. This soon gave way to an improved user interface using a hypervisor approach where a single instance of Dynamips could be initiated which accepted commands over a TCP pipe, usually on port
7200, so chosen because the Cisco 7200 was the first router to be emulated.
For a bit of fun, why not check out the Dynamips hypervisor yourself. From a command line, start Dynamips as a hypervisor running on port
7200 using the command: ...