Skip to content
Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

network emulation

Deliberately adding loss, delay or outages to a network so you can test how software copes.

Network emulation injects loss, delay, reordering and outages (for example Linux netem, or a proxy that drops connections) so failure handling can be tested repeatably on your own machine.

Examples

  • sudo tc qdisc add dev lo root netem delay 200ms 50ms loss 5% delays and drops packets on Linux's loopback interface.

  • A small Python proxy can cut the connection for a 4-minute outage to check that backoff and the offline queue really work.

See also

network failure packet loss exponential backoff offline queue
Read the full section →