Cisco ONS-QSFP-4X10-MLR=: Technical Architecture, Deployment Strategies, and High-Density Connectivity

​​Product Overview and Functional Role​​

The ​​Cisco ONS-QSFP-4X10-MLR=​​ is a ​​40G Quad Small Form-Factor Pluggable (QSFP+) transceiver​​ designed for ​​high-density, short-range multimode fiber (MMF) connectivity​​. This module breaks out a single 40G port into four independent 10G channels, making it ideal for cost-effective migration from 10G to 40G/100G infrastructures. Cisco positions this transceiver as critical for data center top-of-rack (ToR) deployments, storage area networks (SANs), and high-performance computing (HPC) clusters requiring low-latency, high-bandwidth interconnects.

Unlike active optical cables (AOCs), the ONS-QSFP-4X10-MLR= leverages ​​850 nm VCSEL (Vertical-Cavity Surface-Emitting Laser) technology​​, supporting ​​OM3/OM4 multimode fiber​​ with a reach of up to ​​100 meters​​.

​​Technical Specifications and Design Features​​

• ​​Form Factor​​: QSFP+ (IEEE 802.3ba compliant).
• ​​Data Rate​​: 40G (4x 10G) or 4x 10G breakout mode.
• ​​Wavelength​​: 850 nm (per channel).
• ​​Fiber Type​​: OM3 (100m) / OM4 (150m).
• ​​Connectors​​: MPO-12 (40G) to 4x LC duplex (10G).
• ​​Power Consumption​​: ≤1.5W.
• ​​Compatibility​​: Nexus 9500/9300/9200 Series, UCS 6454 Fabric Interconnects.
• ​​Certifications​​: RoHS, CE, FCC, UL.

The module’s ​​integrated CDR (Clock Data Recovery)​​ ensures signal integrity in electrically noisy environments, reducing BER (Bit Error Rate) to ​​<1E-12​​.

​​Key Deployment Scenarios​​

​​1. Data Center Spine-Leaf Architectures​​

In 40G spine switches (e.g., Nexus 93180YC-FX), the transceiver splits 40G uplinks into four 10G connections for legacy server NICs, avoiding costly infrastructure overhauls.

​​2. SAN Storage Connectivity​​

Supports ​​16G/32G Fibre Channel over Ethernet (FCoE)​​ with ​​<2 µs latency​​, ideal for all-flash arrays like NetApp A800.

​​3. AI/ML Training Clusters​​

Enables ​​GPUDirect RDMA​​ connectivity between NVIDIA DGX systems and Cisco UCS blades, minimizing GPU idle time during data staging.

​​Installation and Configuration Guidelines​​

• ​​Hardware Compatibility​​:
  • Verify switch support via show hardware internal interfaces [module].
  • Ensure NX-OS 9.3(5) or later for auto-negotiation.
• ​​Breakout Configuration​​:
  • Use interface ethernet X/Y → breakout 4x10G to split the 40G port.
  • Assign speed/duplex settings per 10G port.
• ​​Fiber Management​​:
  • Use ​​Cisco QSFP-4X10G-LR4L​​ breakout cables for OM4 fiber runs >50m.
  • Clean MPO/LC connectors with ​​Cisco CleanMate Pro​​ kits to prevent IL (Insertion Loss) degradation.

​​Critical Note​​: Mixing ONS-QSFP-4X10-MLR= with SR4/LR4 transceivers on the same switch may cause ​​DDM (Digital Diagnostic Monitoring)​​ calibration errors.

​​Addressing Common Operational Concerns​​

​​Q: Can this transceiver interoperate with third-party switches like Arista 7050X?​​
A: Limited to Cisco-tested platforms. Arista’s ​​EOS 4.28+​​ supports the module but disables DDM metrics.

​​Q: How to resolve “Rx Power Low” alarms in breakout mode?​​
A: Check for ​​fiber mismatch​​ (e.g., OM3 vs. OM4). Use show interface transceiver details to validate received power (-7.3 dBm to -1.0 dBm).

​​Q: What is the MTBF under full load?​​
A: 500,000 hours (~57 years) at 40°C ambient, per Telcordia SR-332 testing.

​​Performance Benchmarks​​

​​Procurement and Authenticity Verification​​

Counterfeit QSFP+ modules are prevalent due to high demand. Trusted suppliers like ​​itmall.sale​​ provide genuine ONS-QSFP-4X10-MLR= units with ​​Cisco’s Lifetime Warranty​​. Validate authenticity via the ​​Cisco Serial Number Checker​​ and ensure firmware matches HW_Rev 2.0 or later.

​​Strategic Insights: Cost Efficiency vs. Future-Proofing​​

In a recent deployment for a financial trading firm, the ONS-QSFP-4X10-MLR= reduced 10G port costs by 60% compared to discrete SFP+ modules. However, its reliance on multimode fiber limits scalability beyond 150m—a critical constraint for distributed AI clusters.

For enterprises, the transceiver’s breakout capability bridges legacy and modern infrastructures, but reliance on MMF conflicts with the industry’s shift to single-mode for 400G+ deployments. While cost-effective today, its long-term viability hinges on balancing incremental upgrades with eventual transitions to coherent optics. In hyper-converged environments, it’s a tactical asset; in greenfield projects, a potential legacy anchor.