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Cisco ONS 15310-MA SDH Reference Manual, Release 9.1 and Release 9.2
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Chapter 7 Circuits and Tunnels
Merged Circuits
Figure 7-12 Dual Roll to Reroute to a Different Node
Note If a new segment is created on Nodes 3 and 4 using the Bridge and Roll wizard, the created circuit has
the same name as the original circuit with the suffix _ROLL**. The circuit source is on Node 3 and the
circuit destination is on Node 4.
7.9.4 Two-Circuit Bridge and Roll
When using the bridge and roll feature to reroute traffic using two circuits, the following constraints
apply:
• DCC must be enabled on the circuits involved in a roll before roll creation.
• A maximum of two rolls can exist between any two circuits.
• If two rolls are involved between two circuits, both rolls must be on the original circuit. The second
circuit should not carry live traffic. The two rolls loop from the second circuit back to the original
circuit. The roll mode of the two rolls must be identical (either automatic or manual).
• If a single roll exists on a circuit, you must roll the connection onto the source or the destination of
the second circuit and not an intermediate node in the circuit.
7.9.5 Protected Circuits
CTC allows you to roll the working or protect path regardless of which path is active. You can upgrade
an unprotected circuit to a fully protected circuit or downgrade a fully protected circuit to an unprotected
circuit with the exception of a Linear Multiplex Section Protection circuit. When using bridge and roll
on Linear Multiplex Section Protection circuits, you can roll the source or destination or both path
selectors in a dual roll. However, you cannot roll a single path selector.
7.10 Merged Circuits
A circuit merge combines a single selected circuit with one or more circuits. You can merge VC
low-order path tunnels, LAP circuits, orderwire and user data channel (UDC) overhead circuits,
CTC-created traffic circuits, and TL1-created traffic circuits. To merge circuits, you choose a master
circuit on the CTC Circuits tab. Then, you choose the circuits that you want to merge with the master
circuit on the Merge tab in the Edit Circuits window. The Merge tab shows only the circuits that are
available for merging with the master circuit:
83102
Node 1
S
D
Node 2
Node 4Node 3
Original leg
New leg
