Summary

  • RFC 5415's state machine records protocol progress, not the whole operational outcome.
  • Control-channel health, configuration consistency and data-channel health are separate evidence surfaces.
  • Current approval requires applied policy, authorization, client sessions and runtime service telemetry.

Join is not permission

CAPWAP discovery and Join allow an AC and WTP to establish a relationship. DTLS protects the control exchange, but cryptographic completion is not a business or operational approval. A device may join the expected controller and still carry stale configuration, fail an authorization rule or never admit a station. The state machine tells an operator where the protocol believes it is; it does not replace the evidence that a policy owner approved the result.

Configure is not continuity

RFC 5415 defines configuration status, update messages and Change State Events so an AC can reason about a WTP's state. That is valuable because it creates checkpoints. It is also why the checkpoints should not be collapsed. A configuration response may describe the device's view at one instant. A later radio failure, fallback event, roaming interruption or data-channel loss can change the service without invalidating the old response. Configuration consistency is a control record, not a client SLO.

Two channels, two failure surfaces

CAPWAP can separate a protected control channel from a data channel, and its Split-MAC and Local-MAC modes place forwarding work in different locations. A green control session therefore cannot certify the data path. Measure keep-alives, encapsulated frames, station association, retransmission and loss separately. When a control state says Run while client counters stop moving, the correct conclusion is divergent evidence, not “healthy.”