Specifications

Chapter 4 Diagnostics and Troubleshooting IPmux-11 Installation and Operation Manual
4-8 Performance Monitoring Statistics
Table 4-2. E1/T1 Statistics (Cont.)
Alarm Description
LCV A Line Code Violation indicates an error on the pulse structure, either a Bipolar Violation (BPV) or an
Excessive Zeros (EXZ) error event.
BPV is the occurrence of a pulse with the same polarity as the previous pulse.
EXZ is the occurrence of a zero string greater than 15 for AMI or 7 for B8ZS.
For an E1 link, the LCV counter will increase by one, for each second during which a BPV or EXZ errors
have occurred.
For T1 links, the LCV counter will increase for each second during which two consecutive BPVs of the
same polarity are received.
Complies with ITU-TI.431, 0.161, G775 and G.821 standards.
Recommendations:
Check physical link for bad/loose connection, impedance matching (balanced or unbalanced) and noisy
environment.
RAI (Yellow) A Remote Alarm Indicator is sent by a device when it enters RED state (looses synch).
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 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 A Far End Block Error 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.