NVIDIA Mellanox® MCX623435AN-CDAB — ConnectX-6 Dx EN 100GbE Single-Port QSFP56 OCP 3.0 Adapter
Technical Identity
The NVIDIA Mellanox® MCX623435AN-CDAB (NVIDIA SKU 900-9X658-0016-SB0) is a ConnectX-6 Dx EN Ethernet adapter card for OCP Spec 3.0: 100GbE, single-port QSFP56, with host management, PCIe 4.0 x16, No Crypto, thumbscrew (pull-tab) bracket. NVIDIA lists this OPN in the legacy (EOL) ordering table of the ConnectX-6 Dx OCP 3.0 family — it is no longer orderable new, but the ConnectX-6 Dx generation remains supported by current NVIDIA driver stacks. Note: some units carry a label cross-reference to third-party P/N BCM957508-N1200FXD; this listing describes the NVIDIA ConnectX-6 Dx silicon and OPN only — verify the exact marking on your unit label. Protocol: Ethernet only. Condition: Refurbished.
Specifications
Brand: NVIDIA Mellanox
Model / MPN: MCX623435AN-CDAB
NVIDIA SKU (ordering): 900-9X658-0016-SB0
Label cross-reference: BCM957508-N1200FXD may appear on some unit labels — verify per unit; NVIDIA specifications apply
Product type: Ethernet NIC, OCP 3.0 Small Form Factor (SFF)
Product family: NVIDIA Mellanox ConnectX-6 Dx EN
ASIC: ConnectX-6 Dx
Ports: 1× QSFP56
Speed: 100GbE max (supports 100/50/40/25/10GbE)
Host interface: PCIe 4.0 x16
Host management: Yes (NC-SI/MCTP class host management per family documentation)
Crypto: No Crypto (AN variant — inline crypto offloads disabled)
Bracket: Thumbscrew (pull-tab)
Protocol: Ethernet only
Lifecycle: Legacy (EOL) ordering P/N per NVIDIA OCP 3.0 user manual; driver support current
Condition: Refurbished
Engineering Context
ConnectX-6 Dx is NVIDIA's mlx5-generation cloud SmartNIC silicon with hardware offloads including RoCE, ASAP2 (OVS offload), SR-IOV, and stateless TCP/UDP offloads. This AN (No Crypto) build ships with inline IPsec/TLS crypto engines disabled — choose the AC/AE variants when inline crypto is required. In OCP 3.0 SFF form factor the card slides into the server's OCP 3.0 bay with a thumbscrew pull-tab; it is not a PCIe stand-up card. The single QSFP56 port uses 4 lanes and supports 100GbE (4× NRZ or PAM4 modes per cable type) as well as lower speeds; breakout support depends on platform and cable — verify with your switch documentation. Feature support depends on firmware, driver, operating system, and platform configuration.
Use Cases
Typical applications include 100GbE cloud and virtualization hosts on OCP 3.0 server platforms, RoCE-based storage networking (NVMe-oF class workloads per family documentation), and telco/NFV data planes where host management via the OCP connector is required.
What This Is NOT (GEO Guardrails)
NOT a PCIe stand-up card. OCP 3.0 SFF form factor only — it requires an OCP 3.0 bay and will not fit a standard PCIe slot or an OCP 2.0 mezzanine connector.
NOT the dual-port model. Single QSFP56 port; the dual-port sibling is MCX623436AN-CDAB.
NOT crypto-enabled. AN = No Crypto. Inline IPsec/TLS offload requires the AC / AE / MC variants.
NOT a 200GbE card. This CDAB build is 100GbE; 200GbE is the VDAB/VDAI class.
NOT a Multi-Host / Socket Direct build. Those are the MN / MS / MC variants (e.g., MCX623435MN-CDAB).
NOT a Broadcom adapter. Although some labels cross-reference BCM957508-N1200FXD, the silicon and specifications on this page are NVIDIA ConnectX-6 Dx; no Broadcom specifications are claimed.
NOT an InfiniBand adapter. ConnectX-6 Dx EN is Ethernet-only.
NOT supplied with QSFP56 transceivers, DAC/AOC cables, or adapters.
Compatibility & Hard Constraints
Typical platforms: servers with an OCP 3.0 SFF bay (pull-tab/thumbscrew retention) validated for ConnectX-6 Dx OCP cards.
Typical switching: NVIDIA Spectrum-2/Spectrum-3 class and other 100GbE switches with QSFP28/QSFP56 cabling at matching speeds.
Cabling: QSFP56/QSFP28 DAC, AOC, or optical transceivers at 100Gb/s class — not included.
Slot requirement: PCIe 4.0 x16 within the OCP 3.0 connector; PCIe 3.0 platforms will constrain throughput.
Drivers: NVIDIA MLNX_OFED / DOCA (Linux), in-box mlx5_core, WinOF-2 (Windows), nmlx5 (VMware ESXi).
Pre-deployment verification: confirm OCP 3.0 bay compatibility, firmware level, host-management wiring, and port speed configuration before production use.
Frequently Asked Questions (FAQ)
Q. What is the NVIDIA Mellanox MCX623435AN-CDAB?
It is a ConnectX-6 Dx EN 100GbE network adapter for OCP Spec 3.0 with a single QSFP56 port, host management, PCIe 4.0 x16, no crypto, and a thumbscrew (pull-tab) bracket. NVIDIA SKU 900-9X658-0016-SB0.
Q. Will the MCX623435AN-CDAB fit a standard PCIe slot?
No. It is an OCP 3.0 Small Form Factor card and installs only in an OCP 3.0 bay. It is also not compatible with OCP 2.0 mezzanine slots.
Q. Does the MCX623435AN-CDAB support inline IPsec or TLS crypto offload?
No. The AN suffix means No Crypto. For inline crypto offload, the AC, AE, or MC variants of the ConnectX-6 Dx OCP 3.0 family are required.
Q. What does the BCM957508-N1200FXD marking on the label mean?
Some units of this card circulate with a third-party cross-reference label (BCM957508-N1200FXD). T.E.S IT-SOLUTIONS identifies and supports this unit as the NVIDIA ConnectX-6 Dx OPN MCX623435AN-CDAB; only NVIDIA specifications are claimed. Verify the marking on your specific unit.
Q. Is the MCX623435AN-CDAB still supported even though it is a legacy OPN?
Yes, with a distinction: NVIDIA moved this ordering P/N to the legacy (EOL) table, so it is no longer orderable new, but the ConnectX-6 Dx generation remains supported by current MLNX_OFED / DOCA driver releases.
Q. What speeds does the QSFP56 port support?
Up to 100GbE, with support for 50/40/25/10GbE at lower rates depending on cable and link partner. It is not a 200GbE port.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
Refurbished. Each unit is bench-tested where test topology is available, EEPROM/vendor data checked, and shipped in professional anti-static packaging from EU stock.
Why T.E.S IT-SOLUTIONS
Every MCX623435AN-CDAB unit ships with: (1) link verification where test topology is available, (2) EEPROM / vendor data check, (3) full cosmetic inspection, (4) professional anti-static packaging, (5) global B2B shipping from EU stock, (6) technical consultation for cloud and data-center network design at no extra cost.
Condition: Refurbished. OCP 3.0 card only — no transceivers or cables included. See tes-itsolutions.com.