Latency Physics Simulator
Calculate and interact with network RTT, light propagation speeds across different mediums, and CPU clock cycles.
Latency Physics Simulator
Calculate and interact with network RTT, light propagation speeds across different mediums, and CPU clock cycles.
Each router/switch adds processing and forwarding delay (~1ms/hop).
In this time, a 3.0 GHz CPU would complete 225,000,000 clock cycles or could process 7.5 MB of JSON in local memory.
How does the physics of network latency work?
1. The Speed of Light is Not Constant in Every Medium
Although in relativistic physics we assume the speed of light in vacuum is approximately 300,000 km/s, it slows down when traveling through dense optical materials.
Internet networks use silica (glass) fiber optics. The glass core's index of refraction (n ≈ 1.5) causes light to propagate about 33% slower than in a vacuum, reducing the actual propagation speed of data to around 200,000 km/s (equivalent to 1 ms per 200 km).
2. Satellites in Vacuum vs. Terrestrial Fiber
Low Earth Orbit (LEO) satellites, like Starlink, beam their electromagnetic signals through the vacuum of space and the upper atmosphere, where the refraction index is practically 1.00.
This means the signal travels 50% faster through space (300,000 km/s) than it would through an undersea fiber optic cable. Thus, for transcontinental connections, LEO satellite theoretical latency can be lower than fiber optics, despite the up-and-down journey.
3. The Cost of Routing (Network Hops)
Pure physical latency due to distance is only the baseline. Every time your data packet moves from one network to another, it traverses switches, border routers, optical amplifiers, and optical-to-electrical-to-optical (OEO) transceivers.
Each device introduces a serialization and queuing delay ranging from 0.2 ms to over 2.0 ms, depending on congestion and node hardware. A typical transatlantic route can involve 10 to 20 network hops, accumulating an additional delay that often exceeds the pure physical delay.