Appendix F - Alarms Troubleshooting MEP Alarm Troubleshooting
Recommended Troubleshooting Procedure
One of the problem defined in
ITU-T Y.1731 detected and
reported as Signaling fault on
MEP (Maintenance End Point)
AID.
AID=MEP.
SIGFLT supported in both
Y.1731 and CFM modes of
work.
All possible defects (known in
SNMP as: errmac, rmepccm,
errccm, xconccm) , except RDI
defect ,are reported as SIGFLT
alarm
SIGFLT alarm is provided with additional information on a
specific reason. The Boolean parameters ERRMAC, RMEPCCM,
ERRCCM, XCONCCM, when set to Y (yes), indicate the
following problems:
ERRMAC: The last CCM received by this MEP from some
remote MEP indicated that the transmitting MEP's associated
MAC is reporting an error status via the Port Status TLV or
Interface Status TLV.
Recommendation: Access the NE where the remote MEP is set.
Check the remote MEP's NE HW status; check HW problems with
PHY or MAC component of the port on the remote NE switch. If
no HW problems found, check the state of the remote MEP (i.e.
local MEP on the remote NE) reported and the connectivity to the
local MEP (i.e. remote MEP on the remote NE).
RMEPCCM: This MEP is not receiving CCMs from some other
MEP in its configured list.
Recommendation:
If changes in the network occurred (e.g. a MEP was deleted
in MA), use Init MEP button on ML MEP pane to re-discover
the new list of remote MEPs.
If no changes in the network, check each remote MEP
locally on it's NE (if they also have this Boolean set to Yes -
the problem is bi-directional). Otherwise, if the problem is in
a single direction, check all paths to the remote
MEP.∙
ERRCCM: This MEP is receiving invalid CCMs or, in Y.1731
mode, ERRCCM is used to indicate UNEXPPERIOD defect , i.e.
CCM is received with different then configured on the MEP
interval (MA/MEG assumption is that all MEPs originate CCM
using the same interval of time, 1sec by default)
Recommendation: Check remote MEP CCM interval
configuration or ensure CCM PDU interoperability between 2 NE,
if possible customize CCM PDU format (for example
SEQNUM=N) on one NE to match with another NE accepted
format.
XCONCCM: This MEP is receiving CCMs that could be from
some other MA or, in Y.1731 mode, XCONCCM is used to
indicate MISMRG or MEGLVL defects.
Recommendation: Change configuration of MEG level, name,
MEP(s) ID or Primary VLAN.
UNEXPMEP: This MEP is receiving messages from unexpected
(not-registered) remote MEP found in MEG .
Recommendation: Add newly discovered MEP as an RMEP to
the alarmed MEP or delete discovered MEP on its own location.
General Note:Not all MEGLVL mismatches can be detected –
this is due to CFM limitations on ML500/600/700 devices : "CFM
Traffic of a layer lower than the lowest CFM Domain defined on
NE is not dropped (as required by the standard) but behaves as a
regular service traffic (dropped or passed as is or passed with
VLAN encapsulation) depending on Port VLAN membership
where CFM traffic appears.
All indications above are Boolean and do not point to the specific
RMEP but indicates the specific type of problem only.
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