Specifications

IPmux-11 Installation and Operation Manual Chapter 4 Diagnostics and Troubleshooting
Performance Monitoring Statistics 4-9
Table 4-2. E1/T1 Statistics (Cont.)
Alarm Description
BES A Bursty Errored Seconds (also known as Errored second type B) is a second during which fewer than
319 and more than one CRC errors occurred with neither AIS nor SEF (Severely Errored Frame)
detected. The BES counter will increase by one for each second containing the condition described
above. The CRC is calculated for the previous frame in order to prevent processing delay.
Complies with AT&T TR-62411 and TR-54016 standards. Not applicable if the line type is set to
Unframed. Available only at T1-ESF or E1-CRC4 modes (performance monitoring functionality).
Recommendations:
Check physical link integrity, G.704 frame format integrity and Sync. (The CRC bits are included in TS0
for E1 multiframe links and in the frame alignment bits for T1 ESF links).
DM A Degraded Minute is calculated by collecting all the available seconds, subtracting any SES and sorting
the result in 60-second groups.
The DM counter will increase by one for each 60-second group in which the cumulative errors during
the 60-second interval exceed 1E-6.
Available in T1-ESF or E1-CRC4 modes only, (performance monitoring functionality).
Recommendations:
See BES recommendations.
ES An Errored Second is a second containing one or more of the following:
• CRC error
• SEF (OOF)
• AIS (T1 only)
• If SES is active ES runs for 10 seconds and then stops.
Recommendations:
Check physical link integrity. Follow the recommendation concerning LOF, BEF and AIS.
SES A Severely Errored Second is a second containing one of the following:
• 320 or more CRC errors events
• One or more OOF defect
• One or more AIS events occurred (T1 only)
• The SES counter will be cleared after reaching 10 and an UAS will then be activated.
Recommendations:
Check physical link integrity. See also ES alarm recommendation.
UAS Unavailable Second parameter refers to the number of seconds during which the interface is
unavailable. The UAS counter will start increasing after 10 consecutive SES occurrences and will be
deactivated as a result of 10 consecutive seconds without SES. After SES clearance the UAS counter will
then diminish 10 seconds from the overall count.
Recommendations:
See above recommendations.
LOMF A Loss of Multi Frame indicates there is no sync on the multi frame mode, i.e., the receiving device is
unable to detect the four ABCD bits pattern on. The LOMF alarm is also indicated by the front panel
ALM LED (red). TS16 MSB in frame 0 for two consecutive multi frames. Available only for E1 Multi-
Frame mode (CAS).
Recommendations:
Check physical link integrity, signaling method (CAS enable only), and framing-related parameters.