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Edge Network Coverage Radius Calculator

The Edge Network Coverage Radius Calculator estimates the maximum one-way geographic radius that can fit inside a round-trip latency target after fixed processing delay is removed. It uses a configurable propagation speed to translate the remaining round-trip propagation time into distance. This is useful for early edge-site placement, latency-zone planning, regional service design, or deciding whether a workload may need compute closer to users before a detailed topology and routing model is available.

The calculation is latency-derived, not radio-derived. It does not estimate wireless signal range or guarantee that a route follows a straight line. Fiber routes, metro paths, peering, switching, queueing, and application processing all consume latency and can make real network distance longer or shorter than simple geography suggests. Treat the result as an upper-bound planning radius under the entered assumptions, then validate candidate sites with measured path latency and the actual network architecture.

Calculator inputs

ms
ms
km/ms
×
Result
—
estimated geographic edge radius
Propagation RTT budget—
Theoretical one-way path length—
Route stretch factor—

1. Set the RTT target
Enter the maximum round-trip latency allowed between the user and the edge service.

2. Reserve fixed delay
Subtract expected processing, switching, queueing, and other non-propagation delay that occurs inside the round trip.

3. Choose effective propagation speed
The default 200 km/ms is a common approximate speed for light in fiber; adjust it if your medium or planning assumption differs.

4. Account for route stretch
Use a factor above 1 when the network path is longer than straight-line geography because of conduit and routing geometry.

5. Review the radius
The result converts the one-way propagation allowance into an estimated straight-line geographic radius after route stretch is applied.

Propagation RTT budget = RTT target − Fixed delayOne-way path length = Propagation RTT budget × Propagation speed ÷ 2Geographic radius = One-way path length ÷ Route stretch factor

Where:

  • RTT target — maximum round-trip latency in milliseconds
  • Fixed delay — round-trip non-propagation latency reserved in milliseconds
  • Propagation speed — effective path speed in kilometers per millisecond
  • Route stretch factor — ratio of network path distance to straight-line geographic distance

Assumptions: The remaining RTT is split evenly into outbound and return propagation. The path uses one effective propagation speed and one route-stretch factor; real networks can be asymmetric.

What the result means

The main result is an estimated straight-line radius that fits within the propagation portion of the selected RTT budget under the entered route assumptions.

A negative propagation budget means fixed processing and queueing already exceed the RTT target, so no positive distance can satisfy the model.

Given:

  • 20 ms round-trip latency target
  • 6 ms fixed processing and queueing
  • 200 km/ms effective propagation speed
  • 1.25× route stretch factor

Calculation:
Propagation RTT budget = 20 − 6 = 14 ms. One-way path length = 14 × 200 ÷ 2 = 1,400 km. Geographic radius = 1,400 ÷ 1.25 = 1,120 km.

Result:
1,120 km estimated geographic edge radius.

Interpretation:
Under these assumptions, users roughly within a 1,120 km straight-line radius could fit inside the propagation share of the 20 ms RTT target; actual routes still need latency measurement.

Why is the round-trip propagation budget divided by two?

The radius is a one-way distance, while the latency target is round trip. Dividing by two assigns half of the remaining propagation time to the outbound path and half to the return path.

Why is propagation speed set below the speed of light in vacuum?

Signals travel more slowly in fiber and other media than light travels in vacuum. The default is a planning approximation, not a universal constant for every route.

What does the route stretch factor do?

It accounts for the fact that real network paths rarely follow a straight geographic line. A 1.25× factor means the routed path is modeled as 25% longer than straight-line distance.

Does this calculate Wi-Fi, cellular, or radio coverage?

No. It estimates a latency-based edge-service radius from propagation time. Radio coverage depends on frequency, power, antennas, terrain, buildings, and interference.

Can the calculated radius guarantee my latency SLA?

No. The result is an upper-bound planning estimate under simplified assumptions. Validate actual RTT, queueing, peering, processing, and path asymmetry before using it for a service-level commitment.