MQTT-over-TLS vs BACnet/SC — The Courier Analogy

The Founder's Explanation (Teach Exactly This Way)

"Two ways to send secured letters from 200 workers. One — give every worker his own passport and sealed envelope, 200 passports to make and renew. Two — hire one trusted courier company; they seal one van, one identity, and carry everyone's letters safely. BACnet/SC is 200 passports. MQTT over TLS is the one trusted courier. At scale, the courier wins."

Teaching the Concept

200 Passports, or One Trusted Courier To send 200 workers' letters securely, you can give each his own passport and sealed envelope — 200 to issue and renew — or hire one trusted courier who seals one van and carries them all. BACnet/SC is the 200 passports; MQTT over TLS is the one courier. At scale, one trusted courier beats 200 passports. Side by Side ``` BACnet/SC (direct) MQTT over TLS cert on EVERY device one cert at the GATEWAY 200 certs to renew 1 cert to renew heavier overhead publish-by-exception (light) inbound config needed outbound TCP 8883 only ``` Why the Courier Wins ``` One gateway cert secures 200 controllers Publish-by-exception: send data only when it changes Outbound-only: no inbound firewall holes ``` BACnet/SC gives every device a passport; MQTT-over-TLS hires one trusted courier — one certificate, one port, all secured.

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Related Topics

• MQTT for IoT in buildings — lightweight publish-subscribe telemetry
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• Browse all Protocols topics — more from this section of the EnSmart BMS Library