nd. Extreme Errored Seconds (EES) Sometimes also referred to as severely errored seconds (SES), this counter incre- ments when a certain threshold of errors is passed in the span of one second. The threshold and the errors to be counted depend on the hardware implementation. You should not see extreme errored seconds on a healthy link, but some errored sec- onds may occur on a normal circuit. SES events are described in RFC 1232 as follows: A Severely Errored Second is a second with 320 or more Code Violation Error Events OR one or more Out of Frame events. Alarms Alarms are serious conditions that require attention. Excessive errors can trigger alarms, as can hardware problems, and signal disruption. The alarms are coded as colors. As with performance events, different vendors define alarms differently, and finding detailed descriptions of them can be challenging. RFC 1232 also describes most alarms, though again, they are described for use in SNMP, and the descriptions are not intended as a standard for hardware implementation. Chapter 20: T1 Red Alarm A red alarm is defined in RFC 1232 as follows: A Red Alarm is declared because of an incoming Loss of Signal, Loss of Framing, Alarm Indication Signal. After a Red Alarm is declared, the device sends a Yellow Signal to the far-end. The far-end, when it receives the Yellow Signal, declares a Yellow Alarm. A red alarm is triggered when a local failure has been detected, or continuous OOF errors have been detected for more than x seconds (vendor-specific). The alarm is cleared after a specific amount of time has elapsed with no OOF errors detected (the amount of time varies by hardware). When a device has a local red alarm, it sends out a yellow alarm. Figure 20-6 shows a sample red alarm. Something has failed on Telecom Switch C. The switch triggers a local red alarm, and sends out the yellow alarm signal to alert its neighbors of the problem. Yellow alarm Red alarm Yellow alarm Telecom Router A Router D Telecom Telecom Switch B Switch C Figure 20-6. Red alarm Figu