3Com SuperStack II PathBuilder S330 Reference Manual page 184

174 C 5: P B
HAPTER ATH UILDER
S330 D P
IAGNOSTICS AND ERFORMANCE
Table 11 T1/E1 UNI with IMA Module Alarms (continued)
Alarm Meaning
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.
Port Missing ICP Two consecutive ICP cells
Cells missing from the IMA frame.
RFI IMA Remote Failure Indication: Far
end IMA Rx networking link
ATM Forum (R-121)
state machines detected LOS,
OOF, AIS. LCD, LIF or LODS.
Test Pattern Failed An 8-bit pattern is sent to the
remote node which must then
echo it back on all ports. The
local node checks the echoed
pattern and reports an alarm if
cells from one or more of the
links fail to arrive. This alarm is
declared on all links which do
not reply or reply incorrectly.
Yellow Alarm OOF alarm is detected. A
received remote alarm
indication means that the far
end equipment has a problem
with the signal it is receiving
from the PathBuilder device.
S
TATISTICS
Troubleshooting Steps
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.
See also Loss of IMA Frame (LIF). This is
a specific cause of that alarm and will
also be reported.
Correct T1 or E1 facilities error.
Make sure that the same number of
links are configured and enabled on
both ends of the IMA configuration.
Make sure that the configuration of
both groups is the same. For instance,
make sure that the payload scrambling
setting is the same on both ends.
Connect an external loopback cable to
the port. If there are no alarms, the
problem is elsewhere. Check for an
open, short, or wiring error in the cable
between the PathBuilder network
interface port and your service
provider's network interface unit, or
the terminal equipment. An open
transmit pair can cause this condition