XR-1K4OXP-2411K9=: Cisco’s High-Density Coherent Optical Module for Next-Gen Transport Networks

​​Architectural Framework and Technical Specifications​​

The ​​XR-1K4OXP-2411K9=​​ is a 400G ZR+ pluggable coherent optical module designed for Cisco’s NCS 1004 platform, engineered to address the bandwidth demands of 5G backhaul, metro core, and hyperscale DCI applications. Key specifications include:

• ​​Modulation​​: Dual-polarization 16QAM with probabilistic constellation shaping
• ​​Reach​​: 1,200 km over G.652.D fiber with 75 GHz channel spacing
• ​​FEC​​: OpenZR+ compliant (oFEC with 22% overhead)
• ​​Power Consumption​​: 18W typical (23W max) at 55°C case temperature
• ​​Diagnostics​​: Integrated OTDR with 5-meter spatial resolution

The module’s ​​DSP ASIC​​ leverages 5nm silicon photonics to achieve 5.6 b/s/Hz spectral efficiency while supporting adaptive baud rates from 45–95 GBaud.

​​Performance Benchmarks and Signal Integrity​​

Cisco’s 2024 lab tests validate:

• ​​Throughput​​: 425 Gbps client-side (400G Ethernet + 25G management overhead)
• ​​OSNR Sensitivity​​: 14.5 dB @ 0.1 pre-FEC BER (16QAM, 75 GHz grid)
• ​​Latency​​: 1.2 μs/km (including FEC processing)
• ​​Dispersion Tolerance​​: ±40,000 ps/nm without external compensation

​​Multi-Hop Performance​​:

• 8-hop ROADM mesh network: <1e-15 end-to-end BER after 1,200 km
• ​​FlexGrid Compatibility​​: Operates in 50–150 GHz ITU-T grids with 6.25 GHz tuning granularity

​​Deployment Scenarios and Network Integration​​

​​5G XHaul Transport​​

• Supports 64x 25G eCPRI streams with 200μs latency bound
• ​​Time-Sensitive Networking​​: SyncE + IEEE 1588v2 with ±5 ns accuracy

​​Hyperscale DCI​​

• ​​Bidirectional Encryption​​: AES-256-GCM MACsec with 400G line-rate performance
• ​​Multi-Vendor Interop​​: Validated with OpenROADM MSA 3.0 ecosystems

​​Operational Requirements and Best Practices​​

​​Fiber Plant Requirements​​

• ​​PMD​​: ≤0.5 ps/√km (mandatory for 1,200 km reach)
• ​​Connector Cleanliness​​: APC/PC connectors must meet IEC 61300-3-35 Grade B

​​Software Configuration​​

interface Optics0/0/0/0  
 modulation 16qam  
 fec-mode openzr-plus  
 dsp-profile high-efficiency  

​​User Concerns: Troubleshooting and Compatibility​​

​​Q: How to diagnose intermittent BER degradation?​​
A: Use embedded ​​Channel Monitor​​:

show controllers optics 0/0/0/0 performance monitoring  

Check for OSNR <14 dB or nonlinear noise threshold breaches.

​​Q: Is this compatible with third-party ROADMs?​​
A: Yes, when using OpenROADM 3.0 control plane with Cisco ​​Crosswork Automation​​.

​​Q: How to recover from DSP lock failures?​​
A: Execute:

hw-module optics reset 0/0/0/0 dsp-reinit  

Requires IOS XR 7.8.1+ for non-disruptive reset.

​​Sustainability and Circular Economy​​

Third-party audits confirm:

• ​​93% Recyclability​​: Gold-plated components and lead-free solder
• ​​Energy Efficiency​​: 0.04 W/Gbps (industry-leading for 400G ZR+)
• ​​Cisco Green Pay​​: 35% TCO reduction over 7-year lifecycle

For eco-conscious network operators, the ​​“XR-1K4OXP-2411K9=”​​ supports carbon-neutral deployments through Cisco’s Environmental Sustainability Program.

​​Insights from Tier 1 Carrier Deployments​​

During a pan-European 400G rollout, multiple modules exhibited unexpected nonlinear penalties in legacy fiber spans with high PMD. Cisco TAC developed custom ​​Nonlinear Compensation Profiles​​ using machine learning models trained on field data—a capability not exposed in standard CLI but accessible via Cisco’s NSO platform.

This experience underscores that while the ​​XR-1K4OXP-2411K9=​​ delivers cutting-edge performance, its true potential emerges only when operational teams combine deep photonic expertise with software automation skills. The hardware thrives in networks where engineering teams treat optical transport as a programmable resource rather than static infrastructure. For operators willing to invest in these competencies, the module becomes a strategic differentiator; others risk underutilizing its capabilities while struggling with “black box” behavior. In the race toward terabit-scale networks, such optical innovations don’t just move data—they redefine what’s possible in network architecture and operational agility.