174 CHAPTER 5: PATHBUILDER S330 DIAGNOSTICS AND PERFORMANCE STATISTICS
Group [n] Multi
IMA ID
Different group IMA ID
received on different links in an
IMA group.
Correct link connections and/or IMA
group configuration.
Group [n] Multi Test
ATM Forum (R-138)
Different test procedure
request from different links in
an IMA group from the far
end.
Use the test procedure from the lowest
logical link and ignore the other test
procedures.
Group [n] Multiple
M
Different frame lengths
received on different links in an
IMA group.
Make sure that the IMA frame length is
set to the same value for all links.
Group [n] Multiple
Symmetry
Different group symmetry
received on different links in an
IMA group (symmetrical versus
asymmetrical operation).
Configure the group to be symmetric.
3Com PathBuilder products do not
support asymmetric bandwidth for
IMA.
Group [n] Time
Sync Fail
The far end transmit clocking
mode does not match the near
end transmit clocking mode
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.
IMA Protocol
Mismatch
IMA label is not ATM Forum
1.0.
Near end and far end IMA protocol
versions do no match. Check and
correct incompatibility.
IMA Remote
Loopback
Far end loopback detected,
external cable loopback or
crosstalk.
Remove loopback condition.
IMA Tx
Misconnected
ATM Forum (R-123)
The near end IMA networking
Tx or Rx link state machine
detects the link is not
connected to the correct FE Tx
or Rx links.
Remove the link and stop Tx and Rx
data.
Loss of Differential
Synchronization
(LODS)
ATM Forum (R-122)
Relative time difference
between individual T1s/E1s in
the IMA group is out of range.
LODS is declared after the Rx
IMA fails to synchronize the
IMA link(s) in an IMA group
within some time limit.
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.
Loss of IMA Frame
(LIF)
ATM Forum (R-121)
Loss of IMA Frame is detected
in the Rx direction for an IMA
link UP.
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.
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.
(continued)
Table 28 DS1/E1 UNI Module Alarms (continued)
Alarm Meaning Troubleshooting Steps
