3Com S330 manual ATM Forum R-123

174CHAPTER 5: PATHBUILDER S330 DIAGNOSTICS AND PERFORMANCE STATISTICS

Table 28 DS1/E1 UNI Module Alarms (continued)

Alarm Meaning Troubleshooting Steps

Group [n] Multi	Different group IMA ID
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)

Group [n] Multiple

M

Different test procedure request from different links in an IMA group from the far end.

Different frame lengths received on different links in an IMA group.

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.

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

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.

IMA Protocol	IMA label is not ATM Forum
Mismatch	1.0.
IMA Remote	Far end loopback detected,
Loopback	external cable loopback or
	crosstalk.

Near end and far end IMA protocol versions do no match. Check and correct incompatibility.

Remove loopback condition.

IMA Tx

Misconnected

ATM Forum (R-123)

Loss of Differential Synchronization (LODS)

ATM Forum (R-122)

Loss of IMA Frame (LIF)

ATM Forum (R-121)

(continued)

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.

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.

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.

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.