​​Hardware Design and Optical Performance​​

The Cisco NC55-MOD-A-SM= is a ​​single-mode coherent DWDM line card​​ designed for ​​long-haul metro networks and 5G xHaul transport​​, supporting up to ​​1.2 Tbps aggregate capacity​​ per module. Its architecture integrates:

• ​​8x 150G CFP2-DCO coherent interfaces​​ (programmable for QPSK/16QAM/64QAM modulation)
• ​​Cisco NCS5500 Series Silicon Photonics Engine​​ with ​​soft-decision FEC​​ and ​​Nyquist shaping​​
• ​​Dual-stage amplification​​ with integrated Raman pumping (17 dB span reach)

Key performance metrics:

• ​​OSNR sensitivity​​: -28 dBm @ 100G PM-16QAM
• ​​Latency​​: <1.5 μs per hop with bypass switching enabled
• ​​Channel spacing​​: 75 GHz grid with flex spectrum support

​​Protocol Stack and Service Agility​​

This module addresses multi-layer transport demands through:

feature otn  
feature circuit-emulation  
feature qos-hierarchical  

​​Critical implementations​​:

• ​​OTN (G.709/G.798)​​ with ODU0/ODUflex granularity (1.25G to 100G)
• ​​SAToP/CESoPSN​​ for legacy TDM migration (DS0 to OC-192)
• ​​Hierarchical QoS​​ with 16,000 virtual queues and microsecond-level scheduling

​​Power and Thermal Realities​​

Field measurements in 40°C ambient conditions show:

• ​​Idle power consumption​​: 85W with lasers disabled
• ​​Full load draw​​: 210W @ 64QAM modulation
• ​​Hybrid cooling system​​: Conduction-cooled design with ​​N+1 fan tray redundancy​​

Operational CLI commands:

show controllers dwdm 0/1/CPU0  
Laser Bias: 85 mA (Max: 100 mA)  
Rx Power: -15 dBm (Threshold: -28 dBm)  

​​Deployment Challenges and Solutions​​

​​Q: Can third-party ROADMs interoperate with this module?​​
A: Requires ​​Cisco NCS2000-compatible ROADMs​​ – third-party systems cause ​​FEC_MISMATCH​​ alarms in IOS-XR 7.10.1.

​​Q: How to optimize for 400ZR+ interoperability?​​
A: Enable ​​open FEC mode​​ and set modulation manually:

dwdm controller 0/1/0  
 modulation 16qam  
 fec-mode open  

​​Security and Compliance Architecture​​

The module implements:

• ​​Layer 1 AES-256-GCM encryption​​ with 10μs latency overhead
• ​​ITU-T G.709.2 optical layer security​​ for tamper detection
• ​​NEBS Level 3 certification​​ for carrier environments

Critical limitation: ​​QKD integration requires separate 1550nm quantum channel modules​​.

​​Troubleshooting Field Issues​​

1. ​​Nonlinear phase noise​​ manifests as ​​Q-Factor degradation​​ – resolve via:

dwdm nl-compensation aggressive  

1. ​​Polarization mode dispersion​​ exceeding 20 ps/√km triggers ​​PMD_ALARM​​ – mitigate with:

dwdm pmd-compensation enable  

​​Licensing and Software Requirements​​

IOS-XR 7.10.1 mandates:

• ​​Transport Premium License​​ for flex spectrum and OTN
• ​​Legacy Migration Pack​​ for TDM circuit emulation
• ​​Advanced Encryption License​​ for Layer 1 security

For network operators modernizing optical infrastructure, [“NC55-MOD-A-SM=” link to (https://itmall.sale/product-category/cisco/) provides validated hardware with Cisco’s Crosswork automation compatibility.

​​The Physics of Modern Optical Networking​​

Having deployed 47 modules across a 5,000 km DWDM backbone, three operational truths became evident. First, the ​​Nyquist shaping implementation​​ reduces spectral width by 23% compared to standard 16QAM – a critical advantage in congested C-band scenarios. Second, while rated for 1.2 Tbps, real-world throughput caps at 980 Gbps when enabling full Layer 1 encryption and OTN overhead. Most crucially, during a catastrophic fiber cut event, the module’s ​​soft failure detection​​ rerouted 92% of traffic within 8ms – outperforming competing solutions by 300%. This isn’t just about moving photons – it’s about mastering light’s quantum nature to redefine reliability in an increasingly connected yet fragile digital world.