CX516A Mellanox 2 Ports 100 Gigabit Ethernet Adapter

Product Overview of CX516A Mellanox 2 Ports Ethernet Adapter

The Mellanox CX516A ConnectX-5 is a high-performance dual-port 100 Gigabit Ethernet network adapter designed for modern data centers, cloud computing, and enterprise networking environments. Built to deliver ultra-fast throughput and low latency, this adapter ensures reliable and scalable connectivity for demanding workloads.

General Information

• Brand: Mellanox
• Manufacturer Part Number: CX516A
• Product Category: Network Interface Adapter

Form Factor and Bus Interface

• Form Factor: Plug-in expansion card
• Bus Interface: PCI Express x16
• PCIe Specification: PCI Express 3.0

Networking Performance

• Total Ports: 2 × 100 Gigabit QSFP28
• Connectivity Type: Wired Ethernet
• Maximum Data Throughput: Up to 100 Gbps

Supported Network Standards

• 1 Gigabit Ethernet (GigE)
• 10 Gigabit Ethernet
• 25 Gigabit Ethernet
• 40 Gigabit LAN
• 50 Gigabit LAN
• 100 Gigabit Ethernet

Advantages of this Mellanox CX516A ConnectX-5 Adapter

• Optimized for high-bandwidth and low-latency networking
• Backward compatibility with multiple Ethernet speeds
• Ideal for virtualization, storage networks, and HPC workloads
• Reliable PCIe 3.0 architecture for stable performance

Unparalleled Architecture and Core Specifications

At the heart of the Mellanox CX516A is the powerful ConnectX-5 ASIC, a 16nm FinFET processor designed for efficiency and performance. This adapter provides two independent ports that each support 100Gb/s data rates using QSFP28 transceivers, offering an aggregate throughput of 200 Gb/s per card. The flexibility of the QSFP28 ports is a key advantage, allowing network architects to deploy the adapter in various configurations—connecting to 100GbE switches directly, or using breakout cables to split each port into 4x 25GbE or 4x 10GbE connections. This future-proofs your investment and enables seamless migration from legacy 10GbE and 40GbE infrastructures to high-performance 25GbE and 100GbE leaf-spine architectures.

Hardware Offload Engine: CPU Efficiency Redefined

A primary differentiator for the ConnectX-5 series is its sophisticated hardware offload engine. By moving critical networking functions from the server CPU to the adapter's dedicated silicon, the CX516A dramatically reduces host overhead, freeing CPU cycles for revenue-generating applications.

Transport Offloads (TCP/UDP/IP)

The adapter provides full stateless offloads for checksum and Large Send Offload (LSO), and stateful offloads like Receive-Side Steering (RSS) for efficient load distribution across CPU cores. This ensures line-rate performance is achievable even with standard Ethernet protocols.

RoCE (RDMA over Converged Ethernet) v2

This is a game-changing technology. The CX516A natively supports RDMA, enabling direct memory-to-memory data movement between servers without involving the operating system or CPUs. This bypasses the traditional TCP/IP stack, slashing latency to under 1 microsecond and drastically improving application response times for databases, storage, and HPC workloads.

NVMe over Fabrics (NVMe-oF) Target and Initiator Support

As storage moves to NVMe, the network becomes the bottleneck. The ConnectX-5's hardware offloads for NVMe-oF allow it to function as a high-performance storage endpoint. This enables the creation of disaggregated, shared storage pools with local-NVMe-like performance over an Ethernet network, revolutionizing data center storage architecture.

Advanced Virtualization and Security Offloads

The card offloads complex virtualization tasks, including SR-IOV (Single Root I/O Virtualization) with support for up to 512 virtual functions. It also provides hardware-based overlay network acceleration for VXLAN, NVGRE, and GENEVE, making it ideal for modern SDN and cloud environments. Embedded Trusted Platform Module (TPM) support enhances security for secure boot and trusted execution.

Target Applications and Workload Optimization

The Mellanox CX516A is not a generic NIC; it is a workload accelerator. Its feature set is tailored to solve specific performance challenges in modern data centers.

High-Frequency Trading and Financial Services

In financial markets, microseconds translate to millions of dollars. The combination of sub-microsecond latency, deterministic performance, and RDMA capabilities makes the CX516A the adapter of choice for trading platforms, risk analysis systems, and real-time analytics, ensuring the fastest possible transaction and data processing times.

Artificial Intelligence and Machine Learning Clusters

AI/ML training involves massive parallel computations across hundreds or thousands of GPUs. The CX516A, especially when paired with Mellanox Spectrum switches, forms a lossless Ethernet fabric that enables GPUDirect RDMA. This allows GPUs in different servers to communicate directly, bypassing the CPU, which is essential for scaling training jobs and reducing model convergence times from days to hours.

Hyperconverged Infrastructure and Software-Defined Storage

Platforms like VMware vSAN, Nutanix, and Ceph demand high-throughput, low-latency networks for node-to-node communication. The RDMA and NVMe-oF capabilities of the ConnectX-5 dramatically improve storage performance and efficiency, allowing for higher VM density, faster rebuild times, and more responsive applications.

High-Performance Computing and Scientific Simulation

For MPI-based applications in research and engineering, efficient message-passing is critical. The CX516A's low latency and high message rate accelerate simulations for climate modeling, computational fluid dynamics, and genomic sequencing, enabling scientists to solve larger problems faster.

Cloud and Telecom Infrastructure

For cloud service providers and telecoms deploying NFV (Network Functions Virtualization), the CX516A delivers the high packet-forwarding rates, robust QoS, and advanced virtualization features needed to host virtual routers, firewalls, and 5G core functions on commercial off-the-shelf servers.

Deployment Considerations and Ecosystem Integration

Successfully deploying the Mellanox CX516A requires an understanding of its physical and software requirements to unlock its full potential.

Hardware Compatibility and Form Factor

The CX516A is a standard PCI Express 3.0 x16 card, compatible with most modern server platforms. It is typically available in a low-profile bracket format, with a full-height bracket often included for flexibility. It requires adequate chassis cooling, as 100GbE operation generates significant heat. Care must be taken to ensure the server's PCIe slot provides sufficient lanes (x8 or x16 recommended) to handle the 200 Gb/s aggregate bandwidth without bottlenecking.

Cabling and Transceiver Options

The QSFP28 ports offer tremendous cabling flexibility:

Direct Attach Copper (DAC): Cost-effective, low-power cables for short reaches (typically up to 3m for 100G). Ideal for top-of-rack connections.
Active Optical Cables (AOC): Integrated optical transceivers with a flexible cable, perfect for distances from 3m to 100m within a data center row or aisle.
Optical Transceivers (SR4, LR4, etc.): Standard QSFP28 modules for multi-mode (SR4) or single-mode (LR4, ER4) fiber, enabling connections from 100m to 40km.

Proper selection depends on distance, density, and budget.

Software Drivers and Management

Mellanox provides the comprehensive MLNX_OFED (Mellanox OpenFabrics Enterprise Distribution) driver suite for Linux, VMware ESXi, Windows, and other operating systems. This includes all necessary drivers, firmware, and management tools. Key software components include:

Mellanox Firmware Tools (MFT): For advanced adapter configuration and firmware updates.
Mellanox WinOF-2: The optimized driver suite for Windows Server environments.
NVIDIA UFM Cyber-AI Platform: For large-scale orchestration, provisioning, and fabric health monitoring in enterprise and HPC deployments (typically used with Mellanox switches).

Integration with industry-standard tools like NVIDIA vSphere, OpenStack, Kubernetes, and Ansible is well-documented and supported.

Comparing ConnectX-5 to Other Generations

Understanding where the CX516A fits in Mellanox's product lineage clarifies its value proposition.

ConnectX-5 vs. ConnectX-4

The ConnectX-5 offers significant upgrades over the ConnectX-4, including double the virtual functions (512 vs. 256), enhanced NVMe-oF offload capabilities, embedded switch functionality for edge cases, and improved packet pacing and QoS features. It represents a more mature and feature-complete 100GbE solution.

ConnectX-5 vs. ConnectX-6 and ConnectX-7

While newer generations like ConnectX-6 and ConnectX-7 offer higher port densities (e.g., 200Gb/s per port) and further enhanced offloads for AI (e.g., SHARP), the ConnectX-5 remains a supremely cost-effective and performant solution for core 100GbE workloads. For many enterprises not yet requiring 200GbE/400GbE, the CX516A provides the optimal balance of cutting-edge features and proven, stable technology at an attractive.