Check whether a planned data-transfer path fits within a round-trip latency target. The calculator estimates fiber propagation delay from route distance, adds per-hop network delay, processing time, and serialization delay, then reports the remaining budget. It is designed for early architecture comparisons; use measured latency when equipment, peering, and route details become available.
A positive margin means the entered components fit inside the target. A negative margin shows how much delay must be removed or how far the target must be relaxed.
The propagation estimate assumes approximately 200,000 km/s in fiber. Wireless, copper, satellite, queues, retransmissions, and indirect routing may require different allowances.
With a 100 ms target, a 1,000 km one-way route, 1.2× route factor, eight 0.5 ms hops, 10 ms processing, and 2 ms serialization, estimated RTT is 28 ms. The remaining budget is 72 ms.
The target is round-trip latency, so the signal travels the one-way route in both directions.
Use a factor derived from known fiber or network routes. If routes are uncertain, compare several scenarios rather than treating one factor as exact.
No. Use per-hop delay for network devices and enter application, server, and queue time in the processing field.
Not accurately with the fiber speed assumption. Enter a measured propagation allowance as processing or use a satellite-specific path model.
The assigned path components exceed the target by the absolute value of the displayed margin.
| Variable | Meaning | Unit |
|---|---|---|
| T | Round-trip target | ms |
| D | One-way route distance | km |
| f | Route inflation factor | ratio |
| P | Processing plus serialization | ms |