The five states
| State | Meaning |
|---|---|
| AUTHENTICATING | A new subscriber's DHCP Discover arrived; the BNG is asking AAA whether to admit them. Transient. |
| OFFERING | AAA said yes; an address has been offered and the data plane pre-programmed. Waiting for the subscriber to confirm. Transient. |
| CONNECTED | Fully online. Traffic flows at line rate; accounting and timers are running. This is the normal steady state. |
| CAPTIVE | Behind the walled garden. The subscriber keeps their IP but can reach only the captive portal — used for unknown subscribers and for expired prepaid sessions. |
| TERMINATING | Being torn down. Final accounting is sent, then the session is removed. Transient. |
Three different kinds of event drive these transitions, and it helps to keep them straight because they show up differently in logs and metrics:
- DHCP events punted up from the data plane (Discover, Request, Release).
- Timer events inside the controller (session expiry, idle expiry, accounting intervals).
- Operator / AAA events via the REST API or RADIUS CoA (disconnect, activate, re-rate).