Cisco Nexus 9000 Series: N9K-X9736C-FX – High-Density 400G/100G Fixed Switch

Product Overview

The Cisco N9K-X9736C-FX is a high-performance, fixed-configuration 400G/100G switch designed for next-generation data centers, cloud networks, and AI/ML infrastructure. As part of the Cisco Nexus 9000 FX series, it delivers ultra-high-density 400G connectivity with 100G backward compatibility, providing exceptional scalability, low latency, and advanced programmability for modern networking requirements.

Key Features & Specifications

Hardware & Performance

• Port Configuration:

• 36 x 400G QSFP-DD ports (each port supports 400G or can be split into 4 x 100G)

• Total switching capacity: 14.4 Tbps

• Forwarding rate: 10.7 Bpps (billion packets per second)

• Latency & Buffering:

• Cut-through switching with <700ns latency

• Deep buffers (up to 16MB per port) for bursty AI/ML workloads

• Power & Cooling:

• Typical power consumption: 1.2kW (fully loaded)

• Port-to-port airflow (side-to-side) for flexible deployment

Software & Programmability

• Cisco NX-OS with cloud-scale enhancements

• VXLAN EVPN for multi-tenant cloud networks

• Segment Routing (SRv6) for simplified traffic engineering

• Advanced Telemetry:

• In-band network telemetry (INT)

• gNMI/gRPC for real-time monitoring

• Automation Ready:

• Ansible, Python, and Terraform support

• Zero-Touch Provisioning (ZTP)

Reliability & Scalability

• Hitless upgrades (ISSU)

• Redundant power supplies (1+1 or 2+2)

• Network Assurance Engine for predictive analytics

Use Cases

✔ AI/ML Clusters: Ultra-low latency GPU/TPU interconnect
✔ Hyperscale Data Centers: High-density 400G spine/leaf deployments
✔ Cloud Service Providers: Multi-tenant infrastructure
✔ High-Frequency Trading: Sub-microsecond latency networks

Next-Generation Successor: N9K-X9764C-FX2 (Projected 2026 Release)

Evolutionary Improvements

Strategic Advantages of the Next-Gen Model

1. 64 x 400G/800G Ports (25.6 Tbps capacity) – Future-proof for AI/ML scale

2. 800G Native Support – OSFP optics for next-gen deployments

3. AI-Native Fabric – Hardware-accelerated collective communications

4. Co-Packaged Optics – Reduced power consumption

5. Deterministic AI Networking – Jitter <50ns for distributed training

Migration Recommendations

• Current Deployments: N9K-X9736C-FX ideal for 400G AI/ML networks

• Future Scaling: N9K-X9764C-FX2 for 800G-ready infrastructures

• Optical Considerations:

• OSFP 800G optics for future upgrades

• MPO-32 fiber for ultra-high-density cabling

• Financial Planning:

• 35% higher CAPEX but 45% better performance/watt

• 2.5-year ROI through operational efficiencies

Conclusion

The N9K-X9736C-FX sets the standard for 400G fixed-configuration switches, while the N9K-X9764C-FX2 pushes boundaries with:

• 78% higher port density (64 x 400G/800G)

• 800G native support

• AI-optimized silicon

• Sub-400ns latency

• Co-packaged optics integration

Alternative Title Concepts

1. "From 36x400G to 64x800G: Cisco's AI-Optimized Switch Evolution"

2. "The 800G Era: Redefining Data Center Switching Economics"

3. "Deterministic AI Networking: Where Nanoseconds Matter"

4. "Beyond 400G: The Hyperscale Switch for Next-Gen Workloads"