NVIDIA Mellanox MCX555A-ECAT (NVIDIA P/N 900-9X5AD-0016-ST0) - ConnectX-5 VPI adapter card: single-port QSFP28, EDR 100Gb/s InfiniBand or 100GbE Ethernet, PCIe Gen 3.0 x16, tall bracket. Condition: Refurbished, tested by T.E.S IT-SOLUTIONS.
Technical Identity
The MCX555A-ECAT is a single-port NVIDIA ConnectX-5 VPI host channel adapter. NVIDIA's ordering description reads "ConnectX-5 InfiniBand/Ethernet adapter card, EDR IB (100Gb/s) and 100GbE, single-port QSFP28, PCIe3.0 x16, tall bracket". The board is low profile at 68.90 x 142.24 mm and ships on a tall full-height bracket. The single QSFP28 cage is Virtual Protocol Interconnect and takes copper or optical media: InfiniBand SDR/DDR/QDR/FDR/EDR, or Ethernet 1/10/25/40/50/100 GbE, selected in firmware. A server host adapter - not a switch, not a BlueField DPU, not a Socket Direct assembly.
Engineering Context
EDR InfiniBand is four lanes at 25.78125 Gb/s NRZ line rate with 64b/66b encoding, giving 100 Gb/s effective on one QSFP28 port; the card is IBTA v1.3 compliant. In Ethernet mode the same lanes carry 100GBASE-CR4, KR4 or SR4, with 50GBASE-R2/R4, 40GBASE-CR4/SR4 and 25GBASE-R on down-negotiation. The host interface is PCI Express Gen 3.0, SERDES @ 8.0 GT/s, 16 lanes (Gen 2.0 and 1.1 compatible). NVIDIA notes a PCIe 3.0 x16 bus supplies a maximum of about 128 Gb/s including overhead - ample for a single 100Gb/s port, which is why the single-port MCX555A-ECAT is not PCIe-limited the way a dual-port Gen 3 card is. Typical board power is 14.2 W with passive cables, maximum 17.0 W passive and 19.7 W with 2.5 W active cables; up to 5 W goes to the QSFP28 module. Airflow heatsink-to-port is 300 LFM passive, 400 LFM with 2.5 W active cables and 950 LFM with 5 W modules. Operating 0 to 55 deg C, altitude to 3050 m. Offloads: RDMA and RoCEv2, GPUDirect RDMA and PeerDirect, NVMe-over-Fabrics target offload, erasure coding, T10-DIF, SR-IOV, ASAP2 Open vSwitch with VXLAN/NVGRE, MPI tag matching.
Deployment & Use Cases
Single-rail EDR InfiniBand compute nodes running MPI over NVIDIA HPC-X or OpenMPI; AI training nodes where one 100Gb/s port per server is enough, using GPUDirect RDMA; NVMe-over-Fabrics initiators and targets; Lustre and Spectrum Scale (GPFS) clients; Ceph and VMware vSAN nodes on RoCEv2.
Technical Specifications
Brand / family: NVIDIA Mellanox ConnectX-5 VPI
MPN / OPN: MCX555A-ECAT
NVIDIA P/N: 900-9X5AD-0016-ST0
Ports: 1 x QSFP28, copper and optical
Port speed: EDR 100Gb/s InfiniBand or 100GbE Ethernet
InfiniBand: SDR/DDR/QDR/FDR/EDR, IBTA v1.3
Ethernet: 1/10/25/40/50/100 GbE
Host interface: PCIe Gen 3.0 SERDES @ 8.0 GT/s, x16 lanes
Form factor: low profile, 68.90 x 142.24 mm, tall bracket
Power: 14.2 W typical / 17.0 W max passive; 5 W to the module
Airflow: 300 LFM passive heatsink-to-port; 950 LFM with 5 W modules
Offloads: RDMA, RoCEv2, GPUDirect RDMA, NVMe-oF, erasure coding, T10-DIF, SR-IOV, ASAP2
Condition: Refurbished - tested by T.E.S IT-SOLUTIONS
Compatibility & Parent Systems
InfiniBand switches: NVIDIA Switch-IB 2 SB7800 (36 x EDR 100Gb/s QSFP28, managed) and SB7890 (externally managed), plus Switch-IB SB7700 / SB7790. Quantum HDR QM8700 / QM8790 ports also link at EDR or HDR100.
Ethernet switches: NVIDIA Spectrum SN2700 (32 x 100GbE QSFP28), SN2410 and SN2100; Spectrum-2 SN3700C and SN3800; Spectrum-3 SN4600C. Third-party 100GBASE-CR4/SR4 ports normally interoperate.
Cabling: QSFP28 - NVIDIA LinkX MCP1600-E series EDR passive DAC, MFA1A00-E series 100G AOC, MMA1B00-E100 multimode transceiver.
Host slot: one PCIe x16 slot, Gen 3.0 electrical or better. Typical hosts: Dell PowerEdge R640/R740, HPE ProLiant DL360/DL380 Gen10, Lenovo ThinkSystem SR630/SR650, Supermicro 1U/2U.
Drivers and port mode: MLNX_OFED (Linux), WinOF-2 (Windows), VMware ESXi and FreeBSD builds, in-box mlx5_core. Set protocol with mlxconfig -d <device> set LINK_TYPE_P1=<IB or ETH>, then reboot.
What This Is NOT
NOT a dual-port card. One QSFP28 cage. The dual-port ConnectX-5 VPI equivalents are MCX556A-ECAT (PCIe Gen 3.0) and MCX556A-EDAT (ConnectX-5 Ex, PCIe Gen 4.0).
NOT a Socket Direct adapter. One PCIe x16 edge connector, no auxiliary card or harness; the Socket Direct ConnectX-5 parts are MCX556M-ECAT-S25 and MCX556M-ECAT-S35A.
NOT PCIe Gen 4. Gen 3.0 x16 at 8.0 GT/s; ConnectX-5 Ex (MCX556A-EDAT) is the Gen 4 part.
NOT HDR or NDR capable. EDR 100Gb/s maximum; HDR needs ConnectX-6, NDR needs ConnectX-7.
NOT a QSFP56, QSFP-DD, OSFP or SFP28 cage. QSFP28 accepts QSFP+ downward but never a QSFP56, QSFP-DD or OSFP module.
NOT a PTP/SMA timing variant - the SMA-bracket part is MCX556A-EDAM. NOT Multi-Host, NOT a BlueField DPU, and NOT supplied with transceivers, cables or risers.
Frequently Asked Questions
Q. What switch models is the MCX555A-ECAT compatible with?
InfiniBand: NVIDIA Switch-IB 2 SB7800 and SB7890 (36 x EDR 100Gb/s QSFP28) and Switch-IB SB7700/SB7790; Quantum HDR QM8700 and QM8790 ports link at EDR or HDR100. Ethernet: Spectrum SN2700, SN2410 and SN2100, Spectrum-2 SN3700C and SN3800, Spectrum-3 SN4600C. Cabling is QSFP28.
Q. Does the MCX555A-ECAT support HDR 200Gb/s or PCIe Gen 4?
No to both. The MCX555A-ECAT is EDR 100Gb/s per port on a PCIe Gen 3.0 x16 host interface at 8.0 GT/s. HDR 200Gb/s needs ConnectX-6 such as MCX653105A-HDAT, and a PCIe Gen 4 host interface needs ConnectX-5 Ex or later.
Q. How do I switch the MCX555A-ECAT between InfiniBand and Ethernet?
Run mlxconfig -d <device> set LINK_TYPE_P1=<IB or ETH> and reboot the host. VPI is a per-port firmware setting; the port carries one protocol at a time.
Q. How does the MCX555A-ECAT differ from MCX556A-ECAT and MCX556M-ECAT-S25?
MCX555A-ECAT is single-port; MCX556A-ECAT is the dual-port version on the same PCIe Gen 3.0 x16 interface; MCX556M-ECAT-S25 is the dual-port Socket Direct build needing two PCIe x8 slots and a 25 cm harness. All three are ConnectX-5 VPI at EDR 100Gb/s or 100GbE per port.
Q. What airflow and power does the MCX555A-ECAT need?
300 LFM heatsink-to-port with passive cables, 400 LFM with 2.5 W active cables and 950 LFM with 5 W modules. Typical board power 14.2 W passive, maximum 17.0 W passive, with up to 5 W to the QSFP28 module.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
Refurbished. Each MCX555A-ECAT is bench-tested for PCIe x16 lane training, QSFP28 link-up, firmware integrity and thermal sensors, then packed anti-static. EU stock. Cables and optics are separate line items.
Why T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS (tes-itsolutions.com) supplies NVIDIA Mellanox networking hardware from EU stock. Every ConnectX adapter is powered up and verified before dispatch - PCIe lane width, port link training and firmware revision. Handling 1-3 business days, international shipping, plus consultation on EDR fabric design and cabling.