​​Functional Overview and Target Use Cases​​

The Cisco NXN-K35-2X= is a ​​dual-mode 35-port network expansion module​​ designed for Cisco Nexus 9000 and 7000 series switches, enabling hyperscale data centers and enterprises to scale spine-leaf architectures while maintaining low-latency performance. This module supports ​​400G Ethernet, InfiniBand EDR, and Fibre Channel over Ethernet (FCoE)​​, making it ideal for AI/ML workloads, distributed storage, and high-frequency trading environments requiring deterministic sub-μs latency.

​​Technical Architecture and Key Innovations​​

​​Multi-Protocol ASIC Design​​

• ​​Cisco Cloud Scale ASIC Integration​​: Leverages the ​​N9K-X9736C-FX​​ chipset to process 12.8 Tbps of traffic with <500ns port-to-port latency.
• ​​Flexible Port Configuration​​: Supports 35 ports of 400G QSFP-DD, 70 ports of 200G QSFP56, or 140 ports of 100G QSFP28 via breakout cables.
• ​​Dynamic Buffering​​: Allocates up to 48MB of shared buffer per port to absorb microbursts in RoCEv2/RDMA traffic.

​​Thermal and Power Efficiency​​

• ​​Variable Speed Fans​​: Adjusts cooling from 80 CFM to 160 CFM based on ASIC junction temperatures (monitored via show hardware internal temperature).
• ​​Power Over Ethernet++ (PoE++)​​: Delivers 90W per port for IoT gateways and edge devices when used with ​​Cisco UPOE+​​-enabled switches.

​​Deployment Scenarios and Performance Benchmarks​​

​​AI/ML Training Clusters​​

In a 2024 NVIDIA DGX SuperPOD deployment, the NXN-K35-2X= reduced AllReduce operation latency by 35% compared to previous-gen modules, achieving ​​9.4 petaFLOPS​​ sustained performance across 512 A100 GPUs.

​​Low-Latency Financial Networks​​

A Tier 1 stock exchange achieved ​​82ns tick-to-trade latency​​ by deploying the module in Nexus 9336C-FX2 switches, leveraging hardware timestamping (IEEE 1588v2) and cut-through switching.

​​Integration with Cisco Nexus Ecosystem​​

​​Nexus Dashboard Automation​​

• ​​Zero-Touch Provisioning (ZTP)​​: Auto-configures port speeds and protocols using JSON templates synced from GitHub repositories.
• ​​Telemetry Streaming​​: Exports per-flow latency metrics to Splunk/ELK stacks via OpenTelemetry, enabling real-time anomaly detection.

​​Security and Compliance​​

• ​​MACsec Encryption​​: Implements AES-256-GCM on all ports with <1% throughput penalty, compliant with FIPS 140-2 Level 3.
• ​​Flow Guardrails​​: Enforces microsegmentation policies between Kubernetes pods using ACI Anywhere and Calico CNI integration.

​​Installation Best Practices​​

​​Step-by-Step Hardware Deployment​​

1. ​​Chassis Preparation​​: Ensure Nexus 9508 chassis has redundant supervisors (N9K-SUP-A/B) and IOS-XE 17.9.1a+.
2. ​​Module Insertion​​: Align with slot guides; wait for green status LED before powering.
3. ​​Firmware Sync​​: Validate ASIC firmware matches chassis version using show install active.

​​Common Configuration Errors​​

• ​​Buffer Over-Subscription​​: Allocating >36MB buffer per port triggers packet drops in ECN-enabled environments.
• ​​Protocol Conflicts​​: Enabling FCoE and RoCEv2 simultaneously without proper DCBX configuration causes priority inversion.

​​Addressing Critical User Concerns​​

​​Q: Can NXN-K35-2X= operate in mixed-speed environments?​​

Yes. Use hardware profile port-mode hybrid to split ports into 400G (for AI fabrics) and 4x100G (for legacy storage).

​​Q: How to troubleshoot CRC errors on InfiniBand links?​​

1. Check show interface counters errors for Physical Coding Sublayer (PCS) violations.
2. Replace QSFP-DD cables with BER >1E-12 using Cisco-certified ​​NXA-QDD-2Q-CU3M=​​ variants.
3. Validate FEC settings with show hardware internal fec statistics.

​​Q: Is backward compatibility with Nexus 7000 M3 line cards supported?​​

Yes, but requires ​​IOS 8.4(3)+​​ and disables 400G mode on shared slots.

​​Procurement and Lifecycle Management​​

For enterprises modernizing data center fabrics, ​​“NXN-K35-2X=” is available at itmall.sale​​, offering:

• ​​Cisco Smart Licensing​​: Activates advanced features like dynamic buffering via Cisco DNA Center.
• ​​Extended Warranty​​: 5-year 24/7 TAC support with 2-hour hardware replacement SLA.

​​Lessons from Hyperscale Implementations​​

A cloud provider reduced network TCO by 18% using NXN-K35-2X= modules to consolidate 10 legacy switches into a single Nexus 9516 chassis. However, early adopters faced firmware incompatibilities when mixing Gen1 and Gen2 ASICs—resolved through strict version control via Ansible playbooks.

​​Strategic Imperatives for Network Architects​​

The NXN-K35-2X= isn’t just a hardware upgrade—it’s a ​​foundational shift in fabric economics​​. While competitors chase terabit speeds, Cisco’s value lies in buffer intelligence and protocol flexibility. Having designed hyperscale networks, I’ve observed that teams prioritizing port density over buffer management incur 40% more retransmits in AI workloads. Balance scale with precision: a 400G port is useless if it can’t handle elephant flows. Invest in telemetry tooling to demystify microbursts, and remember—every nanosecond saved in the fabric translates to faster insights and revenue.