NVIDIA ConnectX-4 Lx Ethernet Adapter Cards for OCP 3.0 User Manual

This is the User Guide for Ethernet adapter cards based on the ConnectX®-4 Lx integrated circuit device. These adapters connectivity provide the highest performing low latency and most flexible interconnect solution for PCI Express Gen 3.0 servers used in Enterprise Data Centers and High-Performance Computing environments.

Important Notes:

  1. ConnectX-4 Lx OCP 3.0 cards were tested for Shock & Vibe in accordance with NVIDIA specifications and setups, as the OCP spec 3.0 available at that time did not contain any S&V definitions. A newer version of the OCP spec 3.0 has defined S&V specifications and NVIDIA is in the midst of retesting these cards to comply with OCP spec 3.0.

  2. In some of the OCP 3.0 cards, the insertion force that is required to install the card into a particular PCI connector may exceed the maximum insertion force that is allowed by the connector’s spec. NVIDIA is updating the OCP 3.0 cards to ensure the proper insertion process.


Please note the following OPN has a thumbscrew bracket. For other retention mechanisms brackets, please contact NVIDIA.

The following provides the ordering part number, port speed, number of ports, and PCI Express speed.

ConnectX-4 Lx for OCP 3.0 Adapter Card Overview

Part Number



Form Factor / Dimensions

Small Form Factor (SFF) / 4.52in. x 2.99in. (115mm x 76mm)

Network Connector Type

Dual-port SFP28

Ethernet Data Rate


10/25 Gb/s

PCI Express Connectors

PCIe Gen 3.0 SERDES @ 8.0GT/s x8 lanes


Thumbscrew Bracket

Host Management


RoHS Compliant

For more detailed information, see Specifications.


This section describes hardware features and capabilities. Please refer to the relevant driver and/or firmware release notes for feature availability.



PCI Express (PCIe)

Uses PCIe Gen 3.0 (8GT/s) through an x8 edge connector. Gen 1.1 and 3.0 compatible.

Up to 25 Gigabit Ethernet

NVIDIA adapters comply with the following IEEE 802.3 standards:

• 25GbE / 10GbE / 1GbE
• IEEE 802.3by, Ethernet Consortium25
• IEEE 802.3by 25 Gigabit Ethernet
• IEEE 802.3ae 10 Gigabit Ethernet
• IEEE 802.3ap based auto-negotiation and KR startup
• Proprietary Ethernet protocols (20/40GBASE-R2, 50GBASE-R4)
• IEEE 802.3ad, 802.1AX Link Aggregation
• IEEE 802.1Q, 802.1P VLAN tags and priority
• IEEE 802.1Qau (QCN)
• Congestion Notification
• IEEE 802.1Qaz (ETS)
• IEEE 802.1Qbb (PFC)
• IEEE 802.1Qbg
• IEEE 1588v2
• Jumbo frame support (9.6KB)


  • SPI - includes one 16MB SPI Flash device (W25Q128FVSIG device by WINBOND-NUVOTON).

Overlay Networks

In order to better scale their 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 effectively addresses this by providing advanced NVGRE and VXLAN hardware offloading engines that encapsulate and de-capsulate the overlay protocol.

RDMA and RDMA over Converged Ethernet (RoCE)

ConnectX-4 Lx, utilizing IBTA RDMA (Remote Data Memory Access) and RoCE (RDMA over Converged Ethernet) technology, delivers low-latency and high-performance over Band and Ethernet networks. Leveraging data center bridging (DCB) capabilities, as well as ConnectX-4 Lx, advanced congestion control hardware mechanisms, RoCE provides efficient low-latency RDMA services over Layer 2 and Layer 3 networks.

NVIDIA PeerDirect™

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 advanced acceleration technology enables higher cluster efficiency and scalability to tens of thousands of nodes.

CPU Offload

Adapter functionality enabling reduced CPU overhead allowing more available CPU for computation tasks.

Quality of Service (QoS)

Support for port-based Quality of Service enabling various application requirements for latency and SLA.

Hardware-based I/O Virtualization

ConnectX-4 Lx provides dedicated adapter resources and guaranteed isolation and protection for virtual machines within the server.

Storage Acceleration

A consolidated compute and storage network achieves significant cost-performance advantages over multi-fabric networks. Standard block and file access protocols can leverage RDMA for high-performance storage access.
• NVMe over Fabric offloads for target machine


ConnectX-4 Lx SR-IOV technology provides dedicated adapter resources and guaranteed isolation and protection for virtual machines (VM) within the server.


The adapter supports a Network Controller Sideband Interface (NC-SI), MCTP over SMBus and MCTP over PCIe - Baseboard Management Controller interface.

Wake-on-LAN (WoL)


Reset-on-Lan (RoL)


  • RHEL/CentOS

  • Windows

  • FreeBSD

  • VMware

  • OpenFabrics Enterprise Distribution (OFED)

  • OpenFabrics Windows Distribution (WinOF-2)

  • Interoperable with 1/10/25 Gb/s Ethernet switches

  • Passive copper cable with ESD protection

  • Powered connectors for optical and active cable support

© Copyright 2023, NVIDIA. Last updated on May 22, 2023.