AT&T DS1/DMi/ISDN-PRI Summary of Generic 1 Maintenance Capabilities, Circuit Pack Alarms

MAINTENANCE AND ALARMS 8-7

Summary of Generic 1 Maintenance Capabilities

Since Generic 1 implements the same DS1, DMI, and ISDN-PRI protocols as Generic 2, both switches provide the same maintenance capabilities. Since Generic 1 DS1s provide conprehensive detection capabilities, the switch usually detects errors caused by network facilities even though an alarm will not trip.

ALARMS

Unlike analog port circuit packs, a DS1 has two categories of alarm signals: circuit-pack-level and facility. Service may be interrupted by either of these alarms. Circuit-pack-level alarms show problems with the circuit pack. Facility alarms show incorrect administration of the interface, cabling between the two switch interfaces, failures in the facility equipment, and performance of the transmission facility. (For facility problems, AT&T maintenance responsibility ends at the network interface.)

Circuit Pack Alarms

There are several types of circuit pack alarms that may arise. These are briefly described next.

Yellow LED

On power-up or initialization, the microprocessor executes a thorough set of tests on the circuit-pack hardware. Failure of any of these initialization tests is shown by a flashing yellow LED. The yellow LED flashes following initialization because of power-up or software requests but does not flash if any failures are detected while the interface is online. Following successful initialization, the yellow LED not flash until the circuit pack is administered and until the D-channel is communicating with the far end. As long as the D-channel is up and communication is established, the LED stays on to show a busy state.

Interface Health

The health alarm is controlled by the microprocessor. If any background tests fail (which the processor runs during normal online operation), the health alarm is set. An example would be a failure of the tests run on the circuits that generate a DS1’s signal. If hardware problems exist, then either the circuit pack will fail power-up initialization tests or the health alarm will be raised again within several seconds of power-up initialization. If the health alarm remains off following initialization, a transient problem may be assumed to have caused the health bit to be set.

NOTE: The circuit pack may fail the initialization tests for reasons other than bad hardware. Known cases are port data interface or port data store problems and synchronization subsystem problems. An example of the latter would be an online clock reference that has been externally looped to itself. These problems are evidenced by all DS1s in a module or in the system failing to initialize properly.