Mellanox NVIDIA CX4421A ConnectX-4 Lx Dual Port SFP28 25GbE OCP 2.0 Mezzanine Network Interface Card (NIC) MCX4421A-ACUN

Enhance your Open Compute infrastructure with the Mellanox NVIDIA ConnectX-4 Lx EN MCX4421A-ACUN, a high-performance dual-port 25GbE OCP 2.0 mezzanine Network Interface Card (NIC) designed for cloud, virtualization, hyperscale, and enterprise data center environments. Featuring two SFP28 ports and built on the reliable ConnectX-4 Lx architecture, this adapter delivers low-latency connectivity, advanced network acceleration, and efficient virtualization performance for modern workloads.

The MCX4421A-ACUN supports up to 25GbE per port and is backward compatible with existing 10GbE SFP+ infrastructure, making it an ideal upgrade path for evolving network environments. Advanced offload technologies including RoCE v1/v2, SR-IOV, VXLAN, NVGRE, GENEVE, and Erasure Coding acceleration help reduce CPU overhead while maximizing throughput and application performance.

Purpose-built for OCP 2.0 Type 1 mezzanine slots, this adapter integrates directly into compatible Open Compute servers without consuming valuable PCIe expansion slots.

Key Features

• Mellanox NVIDIA ConnectX-4 Lx EN Controller
• Model: MCX4421A-ACUN
• Dual-Port 25GbE Ethernet Connectivity
• Two SFP28 Ports
• OCP 2.0 Type 1 Mezzanine Form Factor
• PCIe 3.0 x8 Interface
• Backward Compatible with 10GbE SFP+
• RoCE v1 & RoCE v2 RDMA Support
• SR-IOV Virtualization Acceleration
• VXLAN, NVGRE & GENEVE Offloads
• Hardware Erasure Coding Acceleration
• UEFI Enabled Firmware
• Optimized for NVMe-oF, iSCSI, and iSER Deployments

Technical Specifications

• Manufacturer: NVIDIA Mellanox
• Part Number: MCX4421A-ACUN
• Controller: ConnectX-4 Lx EN
• Form Factor: OCP 2.0 Type 1 Mezzanine
• Interface: PCIe 3.0 x8
• Ports: 2 x SFP28
• Speed: Up to 25GbE per port
• Maximum Aggregate Bandwidth: 50Gbps
• Protocol Support: Ethernet Only
• Host Management: Not Supported (ACUN Variant)
• Port Power Output: Up to 1.5W per SFP28 Port
• Firmware: UEFI Enabled

Compatible Server Platforms

The MCX4421A-ACUN is specifically designed for systems featuring an OCP 2.0 Type 1 mezzanine slot, including:

• Quanta QCT Servers
• Wiwynn Data Center Platforms
• ZT Systems Nodes
• Inspur OCP Servers
• Open Compute Project (OCP) Infrastructure
• Select Dell PowerEdge C-Series Cloud Servers
• Hyperscale and Multi-Node Data Center Platforms

Not Compatible With

• Standard PCIe x8 or PCIe x16 Slots
• Dell rNDC Network Daughter Card Slots
• HPE FlexibleLOM Interfaces
• Standard Tower Servers and Workstations
• Lenovo ThinkSystem PCIe Adapters
• OCP 3.0 SFF and TSFF Slots

Supported Cables & Transceivers

• SFP28 DAC Copper Cables
• SFP28 Active Optical Cables (AOC)
• 25GbE SFP28 SR and LR Optical Transceivers
• 10GbE SFP+ Optical Modules
• Passive and Active Twinax Cables
• LC Duplex Fiber Optic Connections

Operating System Compatibility

Supported by major enterprise and cloud operating systems:

• VMware ESXi 7.x and 8.x
• Microsoft Windows Server 2019 & 2022
• Red Hat Enterprise Linux (RHEL)
• Rocky Linux
• AlmaLinux
• Ubuntu Server LTS
• Debian Linux
• SUSE Linux Enterprise Server (SLES)

Ideal Applications

• Open Compute Project (OCP) Deployments
• Cloud Data Centers
• Virtualization Clusters
• Hyper-Converged Infrastructure
• NVMe over Fabrics (NVMe-oF)
• Software-Defined Storage
• Enterprise Networking
• High-Density Compute Environments
• AI and Machine Learning Infrastructure