Specifications
Confirm model, interface type, rate, power, airflow and software version before ordering.
Selection answer
MCX556A-ECAT can enter a shortlist when a server needs a ConnectX-5 VPI adapter for a confirmed InfiniBand or Ethernet design. The retained record identifies FDR/EDR InfiniBand, 40/50/100GbE, a QSFP28 network interface, PCIe 3.0 x16 and RDMA support. It does not establish the exact port count, bracket, firmware bundle or current support status, so those items must be checked against the complete ordering code before purchase.
Retained specification baseline
| Decision item | Retained page evidence | Project verification |
|---|---|---|
| Adapter family | ConnectX-5 VPI | Complete OPN, hardware revision and supported firmware |
| Network modes | FDR/EDR InfiniBand and 40/50/100GbE are listed | Required protocol, link rate and peer-device mode |
| Network connector | QSFP28 | Optic, DAC or AOC OPN, distance, FEC and peer compatibility |
| Host interface | PCIe 3.0 x16 and 8.0 GT/s are listed | Available slot width, lanes, BIOS settings and NUMA placement |
| Software | RHEL/CentOS, Windows, FreeBSD, VMware, OFED and WinOF-2 are named | Exact OS, kernel, driver, firmware and support matrix |
Suitable and unsuitable situations
- Suitable for evaluation: a server refresh or lab build with a defined VPI protocol, peer switch, cable plan and available PCIe x16 slot.
- Requires a controlled test: mixed firmware, virtualization, storage traffic, RoCE, or an operating-system release not confirmed by the retained page.
- Not ready to order: projects that only specify “100G adapter” and have not identified the server slot, airflow, connector, peer port or software stack.
How to compare MCX556A-ECAT and MCX555A-ECAT
The two retained pages list the same high-level protocol, connector and host-interface fields. They do not provide enough evidence to infer a port-count or form-factor difference. Compare the two complete OPN data sheets, mechanical drawings, bracket options and supported firmware rather than choosing from the shared family description.
Procurement checks
- Record the complete server model, CPU/NUMA layout, free PCIe slot and bracket height.
- State InfiniBand or Ethernet mode, target link rate and the exact peer switch port.
- Match the QSFP28 optic, DAC or AOC to both endpoints, distance and cabling route.
- Confirm the OS, kernel, driver, firmware, management tools and upgrade sequence.
- Place the full adapter, cable, bracket and accessory ordering codes on the bill of materials.
Acceptance test path
- Verify device enumeration, negotiated PCIe width and firmware/driver pairing.
- Bring up every planned network link and record mode, rate, FEC and error counters.
- Run representative RDMA, storage or application traffic; do not substitute a single synthetic result for workload evidence.
- Test reboot, link loss, switch-port recovery, monitoring and rollback before production use.
FAQ
Does QSFP28 guarantee compatibility with every 100G cable?
No. The cable or optic OPN, protocol, distance, FEC, firmware and both endpoint support lists must match.
Can the page be used to confirm a dual-port configuration?
No. The retained record does not state port count. Confirm the mechanical layout and complete OPN documentation.
Is the listed operating-system family enough for deployment approval?
No. Approval requires the exact OS and kernel release, driver, firmware and support matrix used by the target server.
Evidence boundary: This rewrite preserves only fields stated in the existing record. It does not confirm price, stock, delivery, authorization, certification, warranty, lifecycle, port count or performance improvement.
Review the InfiniBand and Ethernet adapter catalog, follow the QSFP28 media compatibility workflow, or prepare the host and cable matrix in the enterprise buyer guide.
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