Context
Synchronous request/response communication across the IT/OT boundary introduces tight coupling between zones.
Under network partition or remote outages, synchronous mechanisms cause producers to block or fail.
BSFG must allow zones to continue operating independently.
Decision
Cross-boundary communication occurs exclusively via asynchronous replay.
Replication loops:
StoreBuffer -> ForwardBuffer
operate independently of application execution.
The network boundary acts only as a transport path; durability is guaranteed before transmission.
Consequences
Benefits:
- partition tolerance
- zone autonomy
- deterministic replay after reconnection
Tradeoffs:
- eventual consistency rather than immediate propagation
- consumers must tolerate delayed updates