Remote site bandwidth

How it is calculated

• Bytes per reported value by transport: about 14 for Sparkplug B, 42 for OPC UA binary, 90 for JSON over MQTT, 8 for a raw Modbus poll.
• Report-by-exception suppresses values before they reach the wire, scaling the rate down linearly.
• Backfill bandwidth is the backlog accumulated during the outage divided by the window you allow it to catch up in — this is the number that sizes the link, not the steady state.
• The recommended plan rounds the peak up to the next 64 kbit/s increment, which is how satellite plans are actually sold.

Where this stops being true

This sizes throughput, and throughput is rarely what breaks a remote site. Geostationary satellite latency is 500 to 700 ms round trip regardless of how much bandwidth you buy, so anything that needs a control loop or an interactive session has to stay at the edge. Rain fade on Ku band takes the link out entirely for minutes at a time, which is a buffer problem rather than a bandwidth one, and contended plans deliver their committed rate and not their advertised one. Size the edge buffer alongside this number, never instead of it.