I had a chassis (HARC and HDSP) completely go off the air. There were no alarm lights and everything appeared totally normal, but all 6 PRIs were giving fast busy. Rebooting the HARC and all HDSPs changed nothing. A few minutes later, rebooted a DSP again and it came up with ALM and Loopback/D-ALM red. Reboot once more and it starts taking calls. Rinse, lather, repeat and on the other 5 HDSPs. In the modem log, I found this: Apr 5 06:03:03 At 20:40:33, Facility "Configurator", Level "CRITICAL":: Illegal device type received in a Device Discovery message, device type: 0, location type: 2, location: <elided>, units: 23. These started just before 06:00 and happened every few minutes until 06:20, when the busy signal condition occurred. There would be a large cluster of them (20-30) each time. The location: info sounds right for an Osaka phone number, so this has me wondering if it was some kind of bogus framing info from the switch (NTT switch) that caused the HARC to fall over, if the problem was really on the switch end, or if this was some odd type of attack. Thoughts? TIA, Jonathan