RAD Data comm IPmux-11 - Manual (Page 102)

Chapter 6 Troubleshooting and Diagnostics Installation and Operation Manual
6-4 Monitoring Performance IPmux-11 Ver. 2.00
Table 6-1. E1/T1 Statistics (Cont.)
RAI (Yellow) Number of seconds with Remote Alarm Indicators. A Remote Alarm Indicator is sent by a device when
it enters RED state (loses sync).
RAI Alarm indicates that the adjacent E1/T1 device had lost E1/T1 synch and hence sent an RAI
towards the IPmux, which entered a Yellow alarm mode (similarly, IPmux sends RAI towards adjacent
E1/T1 when IPmux enters LOF state (Red alarm).
In both E1/T1 links the RAI counter increases by one for each second during which an RAI pattern is
received from the far end framer.
The RAI alarm is also indicated by the front panel ALM LED (red).
Recommendations:
Check reason for E1/T1 device to be in LOF (out of synch state) by checking physical link integrity at
the Tx direction of the IPmux towards E1/T1 device and framing related parameters.
AIS Number of seconds with Alarm Indication Signals. An Alarm Indication Signal implies an upstream
failure of the adjacent E1/T1 device. AIS will be sent to the opposite direction of which the Yellow
alarm is sent.
For E1 links, the AIS counter will increase by one for each second during which a string of 512 bits
contains fewer than three zero (0) bits.
For T1 links, the AIS counter will increase by one for each second during which an unframed “all 1”
signal is received for 3 msec.
The AIS condition is indicated by the front panel E1/T1 SYNC LED (red).
Recommendations:
Check why the E1/T1 device is sending AIS (all ones) stream towards IPmux, for example, Red alarm on
a different interface of E1/T1 device (upstream).
FEBE Number of seconds with Far End Block Errors. The FEBE is sent to transmitting device notifying that a
flawed block has been detected at the receiving device. Exists only for E1 MF-CRC4. The FEBE alarm is
also indicated by the front panel ALM LED (red).
The FEBE counter will increase by one for each second during which the FEBE indication is received.
Recommendation:
Check physical link integrity.
BES Bursty Errored Seconds (also known as Errored seconds type B) are seconds during which fewer than
319 and more than one CRC errors occurred with neither AIS nor SEF (Severely Errored Frames)
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.