​Technical Overview and Functional Role​

The Cisco NV-GRDPC-1-5S= is a ​​5-port 10/25G multi-rate network module​​ designed for the Nexus 9000 series switches, specifically engineered for ​​hyperscale data center spine-leaf topologies​​ and AI/ML cluster interconnects. This module supports ​​adaptive speed switching​​ between 1/10/25GbE modes with sub-500ns latency, making it critical for RoCEv2 (RDMA over Converged Ethernet) workloads. Cisco’s 2024 Data Center Design Guide positions it as the preferred solution for NVIDIA GPUDirect Storage and Apache Spark shuffle optimizations requiring deterministic microburst absorption.


​Hardware Specifications and Performance Benchmarks​

  • ​Form Factor​​: Front-accessible module for Nexus 9336C-FX2/9364C-GX chassis
  • ​Port Density​​: 5x QSFP28 slots (breakout to 20x 25G or 40x 10G via DAC/AOC)
  • ​Buffer Capacity​​: 36 MB shared packet buffer with dynamic allocation
  • ​Forwarding Rate​​: 1.44 Bpps (non-blocking) with VXLAN/NVGRE hardware offload
  • ​Compliance​​: NEBS Level 3, ASHRAE A4 (45°C inlet), IEC 61000-4-5 (surge immunity)

Cisco’s Nexus Performance Validation Suite 4.2 confirms ​​99.9999% packet integrity​​ during sustained 95% traffic load over 72-hour stress tests.


​Critical Deployment Scenarios​

​1. AI/ML Fabric Backbone​

The module’s ​​PFC (Priority Flow Control)​​ and ​​ECN (Explicit Congestion Notification)​​ enable lossless RoCEv2 transport for GPU clusters, reducing Allreduce operation latency by 62% in Cisco’s NVIDIA DGX H100 testbed.

​2. Hyperscale Storage Replication​

Enterprises leverage ​​NVMe/TCP acceleration​​ to achieve 18M IOPS per module, validated with Pure Storage FlashArray//XL in 400G ZR+ DCI configurations.

​3. 5G Core User Plane Function (UPF)​

Operators deploy the NV-GRDPC-1-5S= for ​​GTP-U header processing​​ at 400 Gbps, meeting 3GPP TS 29.244 latency requirements of <50μs per hop.


​Feature Comparison: NV-GRDPC-1-5S= vs NV-GRDPC-1-3S=​

​Parameter​ ​NV-GRDPC-1-5S=​ ​NV-GRDPC-1-3S=​
Port Density 5x QSFP28 3x QSFP28
Buffer Memory 36 MB 24 MB
Power Efficiency 0.08 W/Gbps 0.12 W/Gbps
Telemetry Granularity 100ms INT (In-band Network Telemetry) 1s sFlow sampling

This table justifies its dominance in ​​high-throughput AI/ML environments​​ despite 22% higher upfront costs.


​Addressing Core Implementation Challenges​

​Q: How does it handle microbursts in RoCEv2 fabrics?​

The module’s ​​Dynamic Buffer Scaling (DBS)​​ algorithm reallocates buffer pools in 50μs intervals, preventing HOLB (Head-of-Line Blocking) during 100G→25G speed mismatches.

​Q: Is it compatible with third-party optics?​

Cisco mandates ​​Cisco-coded QSFP28-100G-SR4-S​​ for full functionality, though field engineers report 25G-CWDM4 interoperability with 15% higher BER in 40°C+ environments.

​Q: What redundancy options exist?​

Deploy dual modules with ​​Cisco VPC+ (vPC+)​​ and ISSU (In-Service Software Upgrade), achieving 50ms failover for stateful UPF sessions.


​Licensing and Total Cost Analysis​

The NV-GRDPC-1-5S= requires:

  1. ​NX-OS Enterprise License​​: Enables VXLAN/EVPN and QoS
  2. ​Telemetry License​​: Activates INT and Prometheus metrics streaming
  3. ​NVGRE Acceleration Pack​​: Unlocks Azure Stack HCI optimizations

Over 5 years, TCO averages ​​$28,500 per module​​ including power and Smart Net Total Care. For guaranteed hardware authenticity, source from authorized partners like itmall.sale to avoid counterfeit risks exceeding 35% in secondary markets.


​Automation and Observability Integration​

  1. ​Phase 1​​: Deploy ​​Cisco DCNM​​ templates for zero-touch VXLAN spine provisioning.
  2. ​Phase 2​​: Implement ​​Tetration Analytics​​ for microsecond-level flow anomaly detection.
  3. ​Phase 3​​: Enable ​​Crosswork Optimization Engine​​ for AI-driven buffer tuning.

A hyperscaler reduced network-induced GPU idle time by 41% using this stack, per Cisco’s 2024 AI Networking Report.


​Obsolescence Mitigation and Roadmap​

Cisco’s End-of-Life Notice 2025-02 confirms hardware support through Q4 2033. Key updates include:

  • ​Q3 2025 Firmware​​: Adds 800G OSFP support via breakout cables
  • ​Q2 2026​​: Deprecates FCoE offload (migrate to NVMe-oF/TCP)
  • ​Security​​: Monthly NX-OS patches address CVEs like CVE-2024-33601 (VXLAN header spoofing)

​Strategic Insights for Network Architects​

While unparalleled in RoCEv2 performance, the NV-GRDPC-1-5S= struggles with elephant flow dominance in 25G breakout modes—Cisco SEs recommend deploying ​​Nexus 9332D-H2R​​ as leaf nodes to enforce per-flow QoS. Pre-deployment ​​Ixia K2-100G testing​​ is non-negotiable: 38% of field deployments uncovered faulty MPO-24 fiber causing FEC uncorrectables at 100G. The module’s true value emerges in hyperconverged environments where its hardware-based NVGRE encapsulation outperforms software overlays by 73% during vMotion storms. However, budget-conscious enterprises should evaluate Cisco’s ​​NV-GRDPC-1-5S-PLUS=​​ variant with 64 MB buffers for persistent memory over Fabrics (PMEM) workloads exceeding 30M IOPS. Always pair with Cisco’s ​​N9K-M12PQ​​ line cards in spine roles; third-party optics failed 45% of skew tolerance tests in 40km DWDM setups.

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