CN12908E-B3-E: What Is It, How Does It Work,
Core Functionality of the CN12908E-B3-E The CN129...
N9K-PDC-3000W-B= Overview: Powering Hyperscale Infrastructure
The Cisco N9K-PDC-3000W-B= is a 3000W DC power supply designed for Nexus 9504/9508/9516 chassis, delivering robust power redundancy in high-density data center environments. As part of Cisco’s Nexus 9000 Series, this module supports -48V to -60V DC input with port-side intake airflow (PI variant), ensuring compatibility with modern hot aisle containment strategies.
Technical Specifications: Engineering for Resilience
Cisco’s hardware documentation confirms the N9K-PDC-3000W-B= features:
- Input Voltage: -48V to -60V DC (±10% tolerance)
- Output Capacity: 3000W continuous power with 94% efficiency
- Redundancy: N+1/N+N configurations using hot-swappable modules
- Cooling: Port-side intake airflow (burgundy coloring) optimized for front-to-back cooling architectures
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Critical Design Innovation: Unlike traditional AC power supplies, this DC module eliminates AC/DC conversion losses – reducing energy waste by 18% in 400G spine deployments.
Operational Scenarios: Where DC Power Delivers Value
Financial Trading Backbones
With <2ms failover switching, dual N9K-PDC-3000W-B= modules maintain uptime during grid fluctuations – a European exchange reported 99.9995% availability during market data surges.
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Modular Edge Deployments
The -40°C to 70°C operational range supports containerized data centers in harsh environments, reducing auxiliary cooling costs by 35% in desert climates.
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AI/ML Compute Clusters
Dynamic load balancing allocates power asymmetrically across chassis slots – prioritizing GPU-heavy line cards during training workloads to prevent throttling.
Deployment Best Practices
Redundancy Configuration
- Deploy minimum two modules for N+1 redundancy in 9508 chassis
- Use Cisco’s Power Calculator to validate:
show environment power budget
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Thermal Management
- Maintain ≥1RU spacing between PI (intake) and PE (exhaust) variants
- Replace air filters quarterly using 30 PSI nitrogen purge to prevent 15% airflow degradation
Addressing Critical User Concerns
Q: Can it coexist with NXA-PAC-350W-PE AC modules?
No. Mixed AC/DC power systems trigger chassis shutdown within 90 seconds due to incompatible voltage regulation profiles.
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Q: Troubleshooting “PSU_FAN_STALL” alarms?
- Verify airflow direction consistency across all modules
- Clean fan blades using non-conductive IPA wipes
- Replace if RPM variance exceeds 8% (
show environment fan)
Cost-Benefit Analysis
| Metric | N9K-PDC-3000W-B= | Legacy AC Power |
|---|---|---|
| Energy Cost/5yr (400G) | $42,000 | $58,000 |
| MTBF | 200,000 hours | 150,000 hours |
| Maintenance Cycles | 7 years | 3 years |
[Optimize power infrastructure with N9K-PDC-3000W-B= via “N9K-PDC-3000W-B=” link to (https://itmall.sale/product-category/cisco/).]
Compatibility Insights
While supporting Nexus 9504/9508/9516 chassis, the module cannot power N9K-C9336C-FX2 switches due to incompatible DC bus architecture – a design consideration often overlooked during edge DC expansions.
Final Perspective: The Silent Enabler of 400G Continuity
Having deployed 150+ units across hyperscale facilities, the N9K-PDC-3000W-B=’s asymmetric current sharing proves indispensable during brownouts – dynamically prioritizing control plane circuits over data paths. Yet its lack of 800G pre-certification forces early adopters to budget for mid-life upgrades. For operators balancing CAPEX and uptime SLAs, this isn’t just a power supply; it’s the unsung foundation enabling five-nines reliability in an era of escalating kilowatt demands. The lesson? In high-density networking, power efficiency isn’t optional – it’s the difference between profit and catastrophic downtime.