This read-only enumeration reports the state of the modem's High Data Rate (HDR/EV-DO) session, including states like open(2), close(3), and addressManagementProtocolSetup(4), among others. An admin uses this to pinpoint whether an EV-DO data session failure is happening during initial address/protocol setup versus after a session was already open and later closed. For example, a modem repeatedly cycling into addressManagementProtocolSetup(4) without reaching open(2) would point to a session negotiation problem rather than a radio coverage problem.