Ericsson RBS 2106 Reference Manual page 375

Aborted frames are those frames ended by an abort flag sequence.
Erroneous frames have the following conditions:
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Disturbances are generated such that all malfunctions related to these
are detected and can be pinpointed by diagnostics, without generating
false alarms.
This supervision is performed with internal links using HDLC type
transmission.
46.4.9 Supervision of LAPD Concentration
Purpose
The purpose is to supervise the length of concentrator uplink message
queues. A fault report is sent when an overflow occurs.
Preconditions and Initiation
The supervising function is initiated when the LAPD concentrator is
started.
Description
The purpose of LAPD concentration is to reduce the number of required
physical links between the BSC and the RBS on the Abis interface.
This is achieved by letting a number of DMRUs use the same subrate
for LAPD signalling on A-bis. To accomplish this, the CMRU shall
concentrate LAPD uplink messages from a number of DMRUs onto one
physical link to the BSC.
The LAPD concentration function is modelled on A-bis with a managed
object, AO CON, which is supported by the RBS.
The supervising function checks the concentrator uplink queues in the
CMRU. If the maximum queue time for a message is exceeded, the
oldest message in the queue shall be removed when a new is inserted.
The fault criteria is set to generate a fault when the message queue is
more than 70% full, or when the message is discarded due to queue
overflow. Fault messages are not removed. The queue time is calculated
using the total number of bytes in the queue and the transmission speed
between the BTS and the BSC. The maximum queue time is set to 120
ms. That corresponds to 960 bytes at a transmission speed of 64 kbps.
46.4.10 Supervision of Environmental Conditions
Purpose
Controlling the climate in the BTS.
EN/LZT 720 0008 P2A
2001-11-28
A CRC-error (Cyclic Redundancy Code, CRC-16).
Frames shorter than 4 bytes.
Frames longer than the maximum frame length (260 bytes).
Not ended on byte boundary.
Data loss caused by lack of buffers or memory access problems.
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Self Test and Supervision
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