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Propagation latency

As explained in Latency

Propagation latency is the time required for a bit or signal to travel across a physical distance or communication path.

Propagation latency is the time required for a bit to travel from one place to another. Calculate it as distance D divided by transmission speed S. section 2.4

A nanosecond across 30 centimeters

At the speed of light, a signal traveling 30 centimeters takes roughly one nanosecond. Across an Ethernet cable, the same idea measures travel along the physical wire. section 2.4

Account for propagation latency carefully in network paths:

  • Sum propagation delays across multiple network hops rather than treating a path as one physical link. section 2.4
  • Separate physical travel time from router processing, packet transmission, and queue waiting; propagation latency alone does not describe total network delay. section 2.4

How Latency covers it

How deep it goes
Defines propagation latency, gives D/S, and explains cumulative multi-hop effects, but stops short of a measurement procedure.
Examples
Uses a 30-centimeter light-speed journey and packet travel across Ethernet cables and multi-hop network paths.
What you can do after
Evaluate network delay by calculating physical travel time and separating it from other per-hop latency components.
How it connects
Distinguishes propagation latency from transmission latency, processing latency, queuing latency, and routing latency.
Cover of Latency
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