Specifications

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Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Chapter 1 Alarm Troubleshooting
Note The E-W-MISMATCH alarm also appears during the initial set up of a ring with its East-West
slot/ports configured correctly. In this instance, the alarm clears itself shortly after the ring setup is
complete.
Note The lower numbered slot on a node is traditionally labelled as the west slot and the higher numbered
slot is labelled as the east slot. For example, Slot 6 is west and Slot 12 is east.
Procedure: Clear the E-W-MISMATCH Alarm with a Physical Switch
Step 1 Diagram the ring setup, including nodes and spans, on a piece of paper or white board.
Step 2 Display the CTC network view and label each of the nodes on the diagram with the same name that
appears on the screen’s network map.
Step 3 Double-click each span to reveal the node name/slot/port for each end of the span.
Step 4 Label the span ends on the diagram with the same information. For example, with Node1/Slot12/Port1
- Node2/Slot6/Port1 (2F BLSR OC48, Ring ID=0), label the end of the span that connects Node 1 and
Node 2 at the Node 1 end as Slot 12/Port 1. Label the Node 2 end of that same span Slot 6/ Port 1.
Step 5 Repeat Steps 3 and 4 for each span on your diagram.
Step 6 Label the highest slot at each node east and the lowest slot at each node west.
Step 7 Look at the diagram. You should see a clockwise pattern of west slots connecting to east slots for each
span.
Step 8 If any span has an east-to-west or west-to-west connection, physically switch the fiber connectors from
the card that does not fit the pattern to the card that will continue the pattern. This should clear the alarm.
Note The physical fiber connector switch is the recommend method of clearing this alarm. This
method reestablishes the logical pattern of connection in the ring. However, you can also use
CTC to recreate the span and identify the misconnected slot/ports as east and west. This is
useful when the misconnected node is not geographically near the troubleshooter.
Procedure: Clear the E-W-MISMATCH Alarm with the CTC
Step 1 Log into the misconnected node. This is the node with both ring fibers misconnected; it is in the middle
of the two nodes that have one of two ring fibers misconnected.
Step 2 Click the Provisioning > Ring tabs.
Step 3 From the row of information for the fiber span, write down the Node ID, Ring ID, and the Slot and Port
in the east line list and west line list.
Step 4 Click the row from Step 3 to select it and click Delete.
Step 5 Click Create.
Step 6 Fill in the Ring ID and Node ID from the information collected in Step 3.