Found that the daqd process had quit on h1nds1.  Last error message in the log file:

Invalid broadcast received; seq=17427618 tp_seq=17427618 gps=1028550222 tp_gps=1028550222 gps_n=62500000 tp_gps_n=125000000

Restarted daqd process.

Note that the daqd process failed in a similar manner on h2nds0 August 6, 2012