Specifications

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Cisco ONS 15454 Installation and Operations Guide, R3.2
March 2002
Chapter 5 SONET Topologies
Bidirectional Line Switched Rings
g. Repeat Steps a – c for each circuit displayed on the Circuits tab.
Step 7 Use information recorded in Step 1 to switch traffic away from the ports of neighboring nodes that will
be disconnected when the node is removed:
Caution Traffic is unprotected during the protection switch.
a. Open the neighboring node that is connected through its east port to the removed node.
b. Click the Maintenance > Ring tabs.
c. From the East Switch list, choose FORCE RING. Click Apply.
d. Open the node that is connected through its west port to the removed node.
e. Click the Maintenance > Ring tabs.
f. From the West Switch list, choose FORCE RING. Click Apply.
Step 8 Remove all fiber connections between the node being removed and the two neighboring nodes.
Step 9 Reconnect the two neighboring nodes directly, west port to east port.
Step 10 If the removed node contained trunk OC48AS cards with K3 bytes mapped to an alternate byte, use the
“Remap the K3 Byte” procedure on page 5-14 to verify and remap, if needed, the BLSR extended bytes
on the newly connected neighboring nodes.
Step 11 Close CTC, then log into a node on the reduced ring.
Step 12 Wait for the BLSR Map Ring Change dialog box to display. (If the dialog box does not display after
10 – 15 seconds, select the Provisioning > Ring tabs and click Ring Map.) When the dialog box
displays, click Ye s.
Step 13 On the BLSR Ring Map dialog box, click Accept.
Step 14 Clear the protection switches on the neighboring nodes:
a. Open the node with the protection switch on its east port.
b. Click the Maintenance > Ring tabs and choose CLEAR from the East Switch list. Click Apply.
c. Open the node with the protection switch on its west port.
d. Click the Maintenance > Ring tabs and choose CLEAR from the West Switch list. Click Apply.
Step 15 If a BITS clock is not used at each node, check that the synchronization is set to one of the eastbound or
westbound BLSR spans on the adjacent nodes. If the removed node was the BITS timing source, use a
new node as the BITS source or select internal synchronization at one node where all other nodes will
derive their timing. (For information about ONS 15454 timing, see the “Setting Up ONS 15454 Timing”
section on page 3-12.)