Datasheet

11-33
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 11 Circuits and Tunnels
11.16.5 Protected Circuits
• 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.
11.16.5 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 an SNCP circuit. When using bridge and roll on SNCP circuits, you can roll
the source or destination or both path selectors in a dual roll. However, you cannot roll a single path
selector.
11.17 Merged Circuits
A circuit merge combines a single selected circuit with one or more circuits. You can merge VCTs, VCA
circuits, VLAN-assigned circuits, VCAT members, orderwire and user data channel overhead circuits,
CTC-created traffic circuits, and TL1-created traffic circuits. To merge circuits, you choose a circuit on
the CTC Circuits tab and the circuits that you want to merge with the chosen (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:
• Circuit cross-connects must create a single, contiguous path.
• Circuit types must be a compatible. For example, you can combine a HOP with a VCA circuit to
create a longer VCA circuit, but you cannot combine a LOP with a HOP.
• Circuit directions must be compatible. You can merge a one-way and a two-way circuit, but not two
one-way circuits in opposing directions.
• Circuit sizes must be identical.
• VLAN assignments must be identical.
• Circuit end points must send or receive the same framing format.
• The merged circuits must become a DISCOVERED circuit.
If all connections from the master circuit and all connections from the merged circuits align to form one
complete circuit, the merge is successful. If all connections from the master circuit and some, but not
all, connections from the other circuits align to form a single complete circuit, CTC notifies you and
gives you the chance to cancel the merge process. If you choose to continue, the aligned connections
merge successfully into the master circuit, and unaligned connections remain in the original circuits. All
connections in the completed master circuit use the original master circuit name.
All connections from the master circuit and at least one connection from the other selected circuits must
be used in the resulting circuit for the merge to succeed. If a merge fails, the master circuit and all other
circuits remain unchanged. When the circuit merge completes successfully, the resulting circuit retains
the name of the master circuit.