3Com SuperStack II PathBuilder S330 Reference Manual page 186

174 C 5: P B
HAPTER ATH UILDER
S330 D P
IAGNOSTICS AND ERFORMANCE
Table 28 DS1/E1 UNI Module Alarms (continued)
Alarm Meaning
Group [n] Multi Different group IMA ID
IMA ID received on different links in an
IMA group.
Group [n] Multi Test Different test procedure
request from different links in
ATM Forum (R-138)
an IMA group from the far
end.
Group [n] Multiple Different frame lengths
M received on different links in an
IMA group.
Group [n] Multiple Different group symmetry
Symmetry received on different links in an
IMA group (symmetrical versus
asymmetrical operation).
Group [n] Time The far end transmit clocking
Sync Fail mode does not match the near
end transmit clocking mode
IMA Protocol IMA label is not ATM Forum
Mismatch 1.0.
IMA Remote Far end loopback detected,
Loopback external cable loopback or
crosstalk.
IMA Tx The near end IMA networking
Misconnected Tx or Rx link state machine
detects the link is not
ATM Forum (R-123)
connected to the correct FE Tx
or Rx links.
Loss of Differential Relative time difference
Synchronization between individual T1s/E1s in
(LODS) the IMA group is out of range.
ATM Forum (R-122) LODS is declared after the Rx
IMA fails to synchronize the
IMA link(s) in an IMA group
within some time limit.
Loss of IMA Frame Loss of IMA Frame is detected
(LIF) in the Rx direction for an IMA
link UP.
ATM Forum (R-121)
There is an IMA frame size
mismatch between two ends
of the circuit. This can be
caused by missing ICP cells
(ATM cells that carry protocol
information), bad IMA ID, bad
sequence number, bad M, bad
offset HEC error or CRC error
in ICP cells. This problem may
occur if the link gets noisy and
there is no AFA to prevent the
ICP from getting corrupted. It
is detected in hardware and
may or may not cause an
operational problem.
(continued)
S
TATISTICS
Troubleshooting Steps
Correct link connections and/or IMA
group configuration.
Use the test procedure from the lowest
logical link and ignore the other test
procedures.
Make sure that the IMA frame length is
set to the same value for all links.
Configure the group to be symmetric.
3Com PathBuilder products do not
support asymmetric bandwidth for
IMA.
Check configuration. Only CTC
(Common Transfer Clock) is supported.
If the far end transport clocking is set to
ITC (Independent Transfer Clock),
change it to CTC.
Near end and far end IMA protocol
versions do no match. Check and
correct incompatibility.
Remove loopback condition.
Remove the link and stop Tx and Rx
data.
Have your carrier verify the time synch
and routing of individual T1s/E1s in the
group. Check the IMA group
configuration to ensure consistency on
the local and remote ends.
Check the IMA group configuration to
ensure consistent frame size on the
local and remote ends. Check links for
evidence of noise. Check to be sure
that AFA is enabled.