3com S330 User Manual

Page of 262
198
C
HAPTER
 5: P
ATH
B
UILDER
 S330 D
IAGNOSTICS
 
AND
 P
ERFORMANCE
 S
TATISTICS
CBR ATM Statistics
ATM cell statistics are cell counts since the last counter reset. On the ATM Statistics 
window, you can reset the counter by entering c. ATM statistics are displayed as a 
list rather than a table. The CBR T1-DSX and CBR E1 ATM Statistics screens display 
the following statistics:
CBR virtual circuits must be present in the database in order to view these 
statistics.
Total Cells Received—Total number of cells received over the virtual circuit.
Total Cells Transmitted—Total number of cells transmitted over the virtual 
circuit.
Total Cell Pointer Errors—Number of cells dropped due to structure pointer 
mismatches.
Total Cells Lost—The difference between the number of cells transmitted and the 
number of cells received.
Total Number of Buffer Underflows—Number of buffer underflows over the 
virtual circuit.
Total Number of Buffer Overflows—Number of buffer overflows over the 
virtual circuit.
Total out of Sequence Errors—Number of cells received with out-of-sequence 
number mismatch.
Total CRC Errors—Number of cells received with uncorrectable sequence number 
CRC error.
Total OAM Cells Received—Number of OAM (Operations, Administration, and 
Maintenance) cells received over the virtual circuit. These cells carry OAM 
information used for network management.
Total OAM Cells Transmitted—Number of Operations Administration and 
Maintenance (OAM) cells transmitted over the virtual circuit.
Current Cell Status—Cell loss period count (for CBR use only).
Data Bytes To (structured data ports only)—The data bytes to the cell bus. Use 
this value to set the DBA Bits Mask CBR port parameter. In most cases, the default 
DBA Bits Mask (127) is appropriate. If you are experiencing problems with a CCS 
circuit, however, you can set the DBA Bits Mask to monitor different bits. Check 
the Data Bytes To value, and set the DBA Bits Mask to that value.
When you check the data bytes, you must first make sure that the circuit is in an 
idle state (phone onhook). If you cannot access the equipment to see whether or 
not the circuit is in idle, then check the data bytes for at least 30 seconds (about 
seven updates). If the 
Data Bytes To value remains the same for 30 seconds or 
more, it is safe to assume that the circuit is in an idle state.