PF06 - Packet handling and loss tolerance

Description of the control

Document how the PST handles packets, specifying the packet-loss rate it can tolerate without loss of communication or data, how it handles reordering, and packet time-to-live.

What this control corresponds to

This control covers how robust the application’s communication protocol is against ordinary network imperfections (lost, out-of-order, or stale packets) - a particularly relevant concern on the less reliable networks serving certain regions of Quebec.

Why this control is important

A public health network runs over links of variable quality (VPN, satellite, or cellular links in remote areas). An application that implicitly assumes a perfect network can silently corrupt clinical data when packets are lost or delayed - far more serious than a merely perceptible slowdown.

How to implement it

• Design critical network exchanges (clinical transactions) with acknowledgment, retry, and duplicate-detection mechanisms.
• Test the application’s behaviour under a simulated packet-loss rate (e.g. 1%, 5%, 10%) and document the threshold beyond which integrity is no longer guaranteed.
• Document how out-of-order packets are handled and the packet expiry (time-to-live / timeout) policy.

How to verify it’s in place

• Request the network resilience test report (simulated loss rate, results).
• Verify no silent clinical data loss is possible below the documented threshold, via a demo or test evidence.
• Confirm consistency with the logging and traceability mechanisms required elsewhere in the grid, useful for detecting a transmission anomaly after the fact.