dummynet is a live network emulation tool, originally designed for testing networking protocols, and since then used for a variety of applications including bandwidth management.
dummynet is a live network emulation tool, originally designed for testing networking protocols, and since then used for a variety of applications including bandwidth management. It simulates/enforces queue and bandwidth limitations, delays, packet losses, and multipath effects. It also implements various scheduling algorithms. dummynet can be used on the machine running the user's application, or on external boxes acting as routers or bridges. dummynet runs within your operating system (FreeBSD, OSX, Linux, Windows) and works by intercepting selected traffic on its way through the network stack, as in the figure above, and passing packets to objects called pipes which implement a set of queues, a scheduler, and a link, all with configurable features (bandwidth, delay, loss rate, queue size, scheduling policy...).
