Nortel Meridian 1 Mini-Carrier Remote Description, Installation, And Maintenance page 113

The performance criteria for which these counts are maintained are as
follows.
• Errored seconds - one or more CRC-6 errors or one or more out-of-frame
errors during the second
• Bursty seconds - More than one and less than 320 CRC-6 errors during
the second.
• Severely errored second (SES) (Not Displayed) - 320 or more CRC-6
errors or 1 or more out-of-frame (OOF) errors during the second
• Unavailable seconds - Unavailable state starts with 10 consecutive
severely errored seconds and ends with 10 consecutive non-severely
errored seconds (excluding the final 10 non-severely errored seconds)
• Frame slip seconds - one or more frame slips in a second
• Loss-of-frame seconds - Loss-of-frame or loss-of-signal for three
consecutive seconds
When the T1 framer is configured for D4 operation, the firmware uses bipolar
violations instead of CRC-6 errors. When using bipolar violations, the total
number of bipolar violations is used as CRC-6 errors in the above
calculations.
The MMI maintains an overall error counter which is a sum of all the errors
counted for the six performance criteria listed above. The error counter may
only be cleared by entering the CLEAR ERROR (C E) command. The
error counter will stop counting at 65,000. The error counter provides an easy
method to determine if an alarm condition has been corrected. Simply clear
the error counter, wait for two to three minutes, and enter a Display
Performance (D P) command. Then check the error counter to see if
any errors have occurred since the counter was cleared.
MMI displays performance-counter reports through the DISPLAY
PERFORMANCE (D P) (see "Checking the carrier performance status" on
page 111).
Mini-Carrier Remote Description, Installation, and Maintenance
Maintenance Page 113 of 150