What is CVR-CPAK-QSFP40=?, Technical Profile and Deployment Use Cases for Cisco QSFP+ Modules

​​Core Definition and Purpose​​

The ​​CVR-CPAK-QSFP40=​​ is a ​​40Gbps QSFP+ (Quad Small Form-Factor Pluggable) transceiver module​​ designed for Cisco’s high-density data center and enterprise switches. It enables high-speed connectivity between network devices using ​​multimode fiber (MMF)​​ with a reach of up to ​​150 meters​​ over OM4 cabling. Unlike generic QSFP+ modules, this Cisco-branded optic is optimized for compatibility with ​​Cisco Nexus 9000 series switches​​ and ​​UCS fabric interconnects​​.

​​Key Technical Specifications​​

• ​​Form factor​​: QSFP+ (IEEE 802.3ba compliant).
• ​​Wavelength​​: 850nm (SR4 standard) for short-range data center links.
• ​​Port density​​: Supports breakouts to 4x10Gbps via MPO-12 to LC duplex fanout cables.
• ​​Power consumption​​: 3.5W max, aligning with Cisco’s energy-efficient DC designs.
• ​​Diagnostics​​: Digital Optical Monitoring (DOM) for real-time temperature and TX/RX power metrics.

​​Compatibility and Use Cases​​

​​Supported Platforms​​

• ​​Switches​​: Nexus 93180YC-FX, 9336C-FX2, 9500 linecards.
• ​​UCS​​: 6454 Fabric Interconnect, 5108 Blade Chassis.
• ​​Legacy devices​​: MDS 9706 Directors (with NX-OS 8.x+).

​​Typical Deployments​​

• ​​Leaf-spine architectures​​: 40G spine uplinks in Nexus-backed fabrics.
• ​​Storage area networks (SAN)​​: Connecting UCS to NetApp FAS arrays via FCoE.
• ​​High-frequency trading​​: Low-latency links between trading engines and market data feeds.

​​User Concerns Addressed​​

​​Q: Does it work with third-party switches like Arista or Juniper?​​

A: No. The CVR-CPAK-QSFP40= uses ​​Cisco’s firmware-locked coding​​, blocking activation in non-Cisco gear. For multi-vendor environments, consider Cisco’s “GLC-TE” compatible third-party optics.

​​Q: Can it handle 100Gbps via speed negotiation?​​

A: No. This is a strict 40G module. For 100G, use QSFP28 variants like ​​QSFP-100G-SR4-S​​.

​​Procurement and Authenticity Verification​​

Cisco has discontinued this module in favor of QSFP28/400G solutions, but ​​itmall.sale​​ stocks refurbished units with full Cisco TAC support eligibility. Critical checks before purchase:

• ​​DOM functionality​​: Test reports should confirm live diagnostics.
• ​​Cisco ONS certificate​​: Validates against counterfeit optics database.
• ​​MPO connector inspection​​: No scratches or debris on fiber interfaces.

​​Strategic Value in a 400G Era​​

While 40G is being phased out in hyperscale clouds, the CVR-CPAK-QSFP40= remains relevant for enterprises with sunk costs in 40G spine layers. In a recent manufacturing network audit I conducted, this module provided a cost-effective path to extend the life of Nexus 93180YC-FX switches until a 2026 refresh cycle. However, for greenfield deployments, bypassing 40G for 100/400G is wiser.

The module’s ​​breakout capability​​ to 10G ports still makes it viable for budget-constrained teams needing to connect legacy 10G storage or IoT devices. Yet, its lack of forward compatibility with 100G-LR4 optics limits long-term flexibility. If your roadmap includes AI/ML workloads requiring massive east-west traffic, prioritize newer optics—this SKU is a stopgap, not a foundation.