NVIDIA MCX4121A-ACAT ConnectX-4 Lx EN 25GbE Adapter for Cloud, Web 2.0, Storage & Analytics

Price Negotiable
Price: Negotiate
MOQ: 1pcs
Delivery Time: Based on inventory
Brand: Mellanox
Product Description
NVIDIA MCX4121A-ACAT ConnectX-4 Lx EN 25GbE Adapter for Cloud, Web 2.0, Storage & Analytics

NVIDIA Networking | ConnectX-4 Lx EN Ethernet Adapter Card

2x 25GbE SFP28  |  PCIe Gen3 x8  |  RoCE  |  Mellanox Multi-Host  |  UEFI
Product Overview

The NVIDIA ConnectX-4 Lx EN adapter card family addresses virtualized infrastructure challenges for today's demanding markets and applications. Providing true hardware-based I/O isolation with unmatched scalability and efficiency, ConnectX-4 Lx EN offers a cost-effective and flexible Ethernet adapter solution for Web 2.0, cloud, data analytics, database, and storage platforms.

The MCX4121A-ACAT is the dual-port 25GbE SFP28 member of the ConnectX-4 Lx EN family, with a PCIe Gen 3.0 x8 host interface and UEFI support. It supports Ethernet speeds of 25, 10, and 1 GbE. The ConnectX-4 Lx EN family provides a combination of 1, 10, 25, 40, and 50 GbE bandwidth, sub-microsecond latency, and a 75 million packets per second message rate.

ConnectX-4 Lx EN includes native hardware support for RDMA over Converged Ethernet (RoCE), Ethernet stateless offload engines, overlay networks, GPUDirect technology, and Mellanox Multi-Host technology. With the exponential increase in usage of data and the creation of new applications, ConnectX-4 Lx EN adapter cards enable data centers to increase operational efficiency, improve server utilization, maximize application productivity, and reduce total cost of ownership (TCO).

Key Features
  • Two 25GbE SFP28 ports (supports 25, 10, and 1 GbE)
  • PCIe Gen 3.0 x8 host interface
  • 1/10/25/40/50 Gb/s speeds across the ConnectX-4 Lx EN portfolio
  • Single and dual-port options
  • Virtualization support with SR-IOV
  • Low latency RDMA over Converged Ethernet (RoCE)
  • Mellanox Multi-Host technology connects up to 4 independent hosts
  • CPU offloading of transport operations
  • Application offloading
  • Mellanox PeerDirect communication acceleration
  • Hardware offloads for NVGRE, VXLAN, and GENEVE encapsulated traffic
  • End-to-end QoS and congestion control
  • Hardware-based I/O virtualization
  • UEFI enabled (x86/Arm)
  • RoHS compliant and ODCC compatible
  • Various form factors available
Technology
Mellanox Multi-Host Technology

Mellanox Multi-Host technology enables data centers to design and build scale-out heterogeneous compute and storage racks, with direct connectivity between compute elements and the network. It works by allowing multiple hosts to connect into a single interconnect adapter, by separating the adapter PCIe interface into several independent PCIe interfaces. Each interface connects to a separate host CPU with no performance degradation. By reducing the number of cables, NICs, and switch ports required by four independent servers from four to one of each, Mellanox Multi-Host reduces data center CAPEX and OPEX.

Additional benefits include remote control of configuration and power state per host, guaranteed host security and isolation, and a single BMC with independent NC-SI/MCTP management channels for each managed host. Mellanox Multi-Host also supports heterogeneous data center architectures, where connected hosts can be x86, Power, GPU, Arm, or FPGA.

I/O Virtualization

ConnectX-4 Lx EN SR-IOV technology provides dedicated adapter resources and guaranteed isolation and protection for virtual machines (VMs) within the server. I/O virtualization with ConnectX-4 Lx EN gives data center administrators better server utilization while reducing cost, power, and cable complexity, allowing more virtual machines and more tenants on the same hardware.

Overlay Networks

Data center operators often create overlay networks that carry traffic from individual virtual machines over logical tunnels in encapsulated formats such as NVGRE and VXLAN. While this solves network scalability issues, it hides the TCP packet from the hardware offloading engines, placing higher loads on the host CPU. ConnectX-4 Lx EN addresses this by providing advanced NVGRE, VXLAN, and GENEVE hardware offloading engines that encapsulate and decapsulate the overlay protocol headers, enabling the traditional offloads to be performed on the encapsulated traffic for these and other tunneling protocols (GENEVE, MPLS, QinQ, and so on). With ConnectX-4 Lx EN, data center operators can achieve native performance in the new network architecture.

RDMA over Converged Ethernet (RoCE)

ConnectX-4 Lx EN supports RoCE specifications delivering low-latency and high-performance over Ethernet networks. Leveraging data center bridging (DCB) capabilities as well as ConnectX-4 Lx EN advanced congestion control hardware mechanisms, RoCE provides efficient low-latency RDMA services over Layer 2 and Layer 3 networks.

Mellanox PeerDirect

Mellanox PeerDirect communication provides high-efficiency RDMA access by eliminating unnecessary internal data copies between components on the PCIe bus (for example, from GPU to CPU), and therefore significantly reduces application run time. ConnectX-4 Lx EN advanced acceleration technology enables higher cluster efficiency and scalability to tens of thousands of nodes.

Storage Acceleration

Storage applications will see improved performance with the higher bandwidth ConnectX-4 Lx EN delivers. Standard block and file access protocols can leverage RoCE for high-performance storage access. A consolidated compute and storage network achieves significant cost-performance advantages over multi-fabric networks.

Host Management and Software Support

Mellanox host management and control capabilities include NC-SI over MCTP over SMBus, and MCTP over PCIe - Baseboard Management Controller (BMC) interface, as well as PLDM for Monitoring and Control DSP0248 and PLDM for Firmware Update DSP0267. All Mellanox adapter cards are supported by Windows, Linux distributions, VMware, FreeBSD, and Citrix XenServer. ConnectX-4 Lx EN supports various management interfaces and a rich set of tools for configuration and management across operating systems.

Additionally, ConnectX-4 Lx EN provides the option for a secure firmware update check using digital signatures to prevent remote attackers from uploading malicious firmware images; this ensures that only officially authentic images produced by Mellanox can be installed, regardless of whether the source of the installation is the host, the network, or a BMC.

Typical Deployments
  • Web 2.0, cloud, and data analytics platforms requiring high bandwidth and low latency
  • Database and storage platforms using RoCE for high-performance storage access
  • Virtualized servers using SR-IOV for VM isolation and guaranteed QoS
  • Overlay networks deploying NVGRE, VXLAN, or GENEVE encapsulation
  • Scale-out heterogeneous compute and storage racks using Mellanox Multi-Host
  • GPU-accelerated clusters using PeerDirect (GPUDirect) communication acceleration
  • Servers requiring remote boot over Ethernet or iSCSI with PXE/UEFI support
Compatibility

The MCX4121A-ACAT uses standard SFP28 connectivity for 25, 10, and 1 GbE links. It is a PCIe Gen 3.0 x8 card and is compatible with PCIe Gen 3.0, 1.1, and 2.0 interfaces, with auto-negotiation to x8, x4, x2, or x1 lanes. It interoperates with 1/10/25/40/50 Gb/s Ethernet switches and supports passive copper cables with ESD protection and powered connectors for optical and active cable support.

Operating system support includes RHEL/CentOS, Windows, FreeBSD, VMware, OpenFabrics Enterprise Distribution (OFED), and OpenFabrics Windows Distribution (WinOF-2), plus Citrix XenServer. UEFI support is enabled for x86 and Arm servers. Because system-level compatibility can depend on server platform, firmware, and OS/driver versions, please confirm the exact host configuration before ordering.

Specifications
Port Configuration and Bandwidth
Parameter Value
Max network speed 2x 25GbE
Interface type SFP28
Supported Ethernet speeds 25, 10, 1 GbE
Form factor PCIe HHHL (half-height, half-length) stand-up card
Additional features UEFI Enabled (x86/Arm)
Dimensions without bracket 14.2cm x 6.9cm (low profile)
Host Interface
Parameter Value
PCIe generation PCIe Gen 3.0 x8
PCIe compatibility PCIe Gen 3.0 compliant, 1.1 and 2.0 compatible
Link rate 2.5, 5.0, or 8.0 GT/s
Lane negotiation Auto-negotiates to x8, x4, x2, or x1 lanes
Interrupt mechanisms MSI / MSI-X
Ethernet Features
Feature Status
50GbE / 40GbE / 25GbE / 10GbE / 1GbE Supported across the portfolio
IEEE 802.3bj, 802.3bm 100 Gigabit Ethernet Supported
25G Ethernet Consortium 25, 50 Gigabit Ethernet Supported
IEEE 802.3ba 40 Gigabit Ethernet Supported
IEEE 802.3ae 10 Gigabit Ethernet Supported
IEEE 802.3az Energy Efficient Ethernet Supported
IEEE 802.3ap based auto-negotiation and KR startup Supported
Proprietary Ethernet protocols (20/40GBASE-R2, 50GBASE-R4) Supported
IEEE 802.3ad, 802.1AX Link Aggregation Supported
IEEE 802.1Q, 802.1P VLAN tags and priority Supported
IEEE 802.1Qau (QCN) Congestion Notification Supported
IEEE 802.1Qaz (ETS) Supported
IEEE 802.1Qbb (PFC) Supported
IEEE 802.1Qbg Supported
IEEE 1588v2 Supported
Jumbo frame support (9.6KB) Supported
Mellanox Multi-Host
Feature Status
Up to 4 separate PCIe interfaces to 4 independent hosts Supported
Two PCIe x4 to two hosts, four PCIe x4 to four hosts, or four PCIe x2 to four hosts Supported
Independent NC-SI SMBus interfaces Supported
Independent stand-by and wake-on-LAN signals Supported
Enhanced Features
Feature Status
Hardware-based reliable transport Supported
Collective operations offloads Supported
Vector collective operations offloads Supported
PeerDirect RDMA (GPUDirect communication acceleration) Supported
64/66 encoding Supported
Extended Reliable Connected transport (XRC) Supported
Dynamically Connected transport (DCT) Supported
Enhanced Atomic operations Supported
Advanced memory mapping support (UMR) Supported
On-demand paging (ODP) Supported
Registration-free RDMA memory access Supported
CPU Offloads
Feature Status
RDMA over Converged Ethernet (RoCE) Supported
TCP/UDP/IP stateless offload Supported
LSO, LRO, checksum offload Supported
RSS (can be done on encapsulated packet), TSS, VLAN insertion/stripping, Receive flow steering Supported
Intelligent interrupt coalescence Supported
Overlay Networks
Feature Status
Stateless offloads for overlay networks and tunneling protocols Supported
Hardware offload of encapsulation and decapsulation of NVGRE and VXLAN overlay networks Supported
Hardware-Based I/O Virtualization
Feature Status
Single Root IOV Supported
Multi-function per port Supported
Address translation and protection Supported
Multiple queues per virtual machine Supported
Enhanced QoS for vNICs Supported
VMware NetQueue support Supported
Virtualization
Feature Status
SR-IOV Virtual Functions Up to 256 Virtual Functions
SR-IOV Physical Functions per port Up to 8 Physical Functions per port
Virtualization hierarchies (e.g. NPAR) Supported
Virtualizing Physical Functions on a physical port Supported
SR-IOV on every Physical Function Supported
Ingress and egress QoS levels Supported
Guaranteed QoS for VMs Supported
Protocol Support
Protocol Status
OpenMPI, IBM PE, OSU MPI (MVAPICH/2), Intel MPI Supported
Platform MPI, UPC, Open SHMEM Supported
TCP/UDP, MPLS, VxLAN, NVGRE, GENEVE Supported
SER, NFS RDMA, SMB Direct Supported
uDAPL Supported
Management and Control Interfaces
Feature Status
NC-SI over MCTP over SMBus Supported
NC-SI over MCTP over PCIe Supported
Baseboard Management Controller interface Supported
SDN management interface for managing the eSwitch Supported
I²C interface for device control and configuration Supported
General Purpose I/O pins Supported
SPI interface to flash Supported
JTAG IEEE 1149.1 and IEEE 1149.6 Supported
Remote Boot
Feature Status
Remote boot over Ethernet Supported
Remote boot over iSCSI Supported
PXE and UEFI Supported
Additional Specifications
Parameter Value
Power consumption Not publicly specified — please confirm before ordering
Operating temperature Not publicly specified — please confirm before ordering
Regulatory compliance RoHS compliant, ODCC compatible
Selection Guide

The ConnectX-4 Lx EN portfolio includes multiple form factors and port configurations. The table below summarizes the PCIe HHHL options described in the product brief. For OCP 2.0 and OCP 3.0 options, please contact your NVIDIA sales representative.

Max Network Speed Interface Speeds (GbE) Host Interface OPN
1x 10GbE SFP28 10, 1 PCIe 3.0 x8 MCX4111A-XCAT
2x 10GbE SFP28 10, 1 PCIe 3.0 x8 MCX4121A-XCAT
2x 10GbE SFP28 10, 1 PCIe 3.0 x8 MCX4121A-XCHT
1x 25GbE SFP28 25, 10, 1 PCIe 3.0 x8 MCX4111A-ACAT
2x 25GbE SFP28 25, 10, 1 PCIe 3.0 x8 MCX4121A-ACAT
1x 40GbE QSFP28 40, 25, 10, 1 PCIe 3.0 x8 MCX4131A-BCAT
1x 50GbE QSFP28 50, 40, 25, 10, 1 PCIe 3.0 x8 MCX4131A-GCAT
2x 25GbE SFP28 25, 10, 1 PCIe 3.0 x8 MCX4121A-ACAT (this part number)
Advantages
  • Cost-effective 25GbE: A flexible Ethernet adapter solution for Web 2.0, cloud, data analytics, database, and storage platforms.
  • High performance: High bandwidth, low latency, and high message rate for demanding applications.
  • Virtualization acceleration: SR-IOV with up to 256 Virtual Functions and guaranteed QoS for VMs.
  • Overlay network offloads: Hardware encapsulation/decapsulation for NVGRE, VXLAN, and GENEVE.
  • Efficient I/O consolidation: Lowers data center costs and complexity with a consolidated compute and storage network.
  • Mellanox Multi-Host: Connects up to four independent hosts through a single adapter, reducing cables, NICs, and switch ports.
  • PeerDirect acceleration: Reduces application run time by eliminating unnecessary PCIe bus data copies.
  • Power efficiency: Designed to help data centers reduce power usage and improve server utilization.
  • Broad platform support: Smart interconnect for x86, Power, Arm, and GPU-based compute and storage platforms.
FAQ
What is the MCX4121A-ACAT?

It is an NVIDIA ConnectX-4 Lx EN Ethernet adapter card with two 25GbE SFP28 ports and a PCIe Gen3 x8 host interface, supporting 25, 10, and 1 GbE speeds.

What speeds does it support?

It supports 25, 10, and 1 GbE on each SFP28 port. The broader ConnectX-4 Lx EN family supports 1, 10, 25, 40, and 50 GbE depending on the part number.

Does it support RDMA?

Yes. It supports RDMA over Converged Ethernet (RoCE) for low-latency, high-performance RDMA services over Layer 2 and Layer 3 networks.

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