Cisco ONS 15454 DWDM - Figure

17-10
Cisco ONS 15454 DWDM Installation and Operations Guide, R6.0
August 2005
Chapter 17 Node Reference
17.1.5 Anti-ASE Node
Figure 17-10 ROADM Optical Signal Flow Example
17.1.5 Anti-ASE Node
In a meshed ring network, the ONS 15454 requires a node configuration that prevents amplified
spontaneous emission (ASE) accumulation and lasing. An anti-ASE node can be created by configuring
a hub node or an OADM node with some modifications. No channels can travel through the express path,
but they can be demultiplexed and dropped at the channel level on one side and added and multiplexed
on the other side.
The hub node is the preferred node configuration when some channels are connected in passthrough
mode. For rings that require a limited number of channels, combine AD-xB-xx.x and 4MD-xx.x cards,
or cascade AD-xC-xx.x cards. See Figure 17-5 on page 17-6.
Figure 17-11 shows an anti-ASE node that uses all wavelengths in the passthrough mode. Use
Cisco MetroPlanner to determine the best configuration for anti-ASE nodes.
1 The OSC-CSM receives the optical signal. It separates the optical service channel from the optical payload and sends the
payload to the OPT-PRE module.
2 The OPT-PRE compensates for chromatic dispersion, amplifies the optical payload, and sends it to the 32WSS.
3 The 32WSS splits the signal into two components. The 80% component is sent to the DROP-TX port and the 20%
component is sent to the EXP-TX port.
4 The drop component goes to the 32DMX where it is de-multiplexed and dropped.
5 The express wavelength aggregate signal goes to the 32WSS on the other side where it is de-multiplexed. Channels are
stopped or forwarded based upon their switch states. Forwarded wavelengths are merged with those coming from the
ADD path and sent to the OSC-CSM module.
6 The OSC-CSM combines the multiplexed payload with the OSC and sends the signal out the transmission line.
32-ch
demux
Side B
OSC-CSM
115228
Side A
OSC-CSM
OSC
Side B
32WSS
Side A
32WSS
80/20
Side B
32DMX
Add
Add
Drop
2 slots
1 slot
Side B
OPT-PRE
S
ide B
Line
Side A
OPT-PRE
Side A
Line
32-ch
demux
Side A
32DMX
Drop
1 slot
32R_OAM
80/20
2 slots
32R_OAM
1
1
2
2
3
3
5
5
6
6
4
4
OSC