NVIDIA Mellanox® MCX621102AN-ADAT — ConnectX-6 Dx 25GbE Dual SFP28 PCIe 4.0 x8 (Refurbished)
Technical Identity
The NVIDIA Mellanox MCX621102AN-ADAT is a refurbished ConnectX-6 Dx EN dual-port 25 Gigabit Ethernet Network Interface Card (NIC). It provides 1/10/25 GbE connectivity over 2× SFP28 cages on a PCIe 4.0 x8 host interface, tall bracket. No-crypto variant (Secure Boot disabled). Ethernet-only ASIC — not VPI/InfiniBand. NVIDIA end-of-life status; refurbished units remain widely deployed in 25GbE access tier, NVMe-oF storage front-ends, and SR-IOV virtualization fabrics.
Specifications

Brand: NVIDIA Mellanox
Model / MPN: MCX621102AN-ADAT
Product family: ConnectX-6 Dx EN (Ethernet)
ASIC: ConnectX-6 Dx
Ports: 2× SFP28
Speed per port: 1 / 10 / 25 GbE (25GbE rated)
Host interface: PCIe 4.0 x8 (backward-compatible to PCIe 3.0 x8 at reduced bandwidth)
Form factor: Half-Height Half-Length (HHHL), tall bracket
Crypto: Disabled — No IPsec / TLS inline crypto
Secure Boot: Disabled
Typical power: ~11 W passive cables, PCIe Gen 4.0
Max SFP28 port power: 1.5 W per port
EOL status: NVIDIA end-of-life — confirm firmware/OS support before purchase
Condition: Refurbished, Grade A — EEPROM-verified, link-tested

Key Features

ConnectX-6 Dx EN — 50G PAM4 SerDes; 2× 25GbE SFP28 line rate
RDMA over Converged Ethernet (RoCE v1 / v2) — CPU-bypass storage and HPC fabrics
NVMe over Fabrics (NVMe-oF) target and initiator hardware offloads
SR-IOV with up to 1K Virtual Functions for cloud/multi-tenant virtualization
ASAP² — hardware-accelerated Open vSwitch (OVS) and connection-tracking offload
VXLAN / NVGRE / GENEVE overlay encapsulation offloads
PCIe Gen 4.0 x8 — efficient host bus for line-rate dual 25GbE workloads

What This Is NOT

NOT a VPI / InfiniBand adapter — ConnectX-6 Dx is Ethernet-only. For VPI dual-protocol, see the MCX653 / MCX654 ConnectX-6 VPI series.
NOT a 100GbE adapter — maximum line rate per port is 25GbE. For 100GbE dual-port over QSFP56, see MCX623106AN-CDAT (PCIe 4.0 x16).
NOT the PCIe 4.0 x16 variant — this is the x8 host interface SKU. For x16 dual 25GbE, see MCX623102AN-ADAT.
NOT a crypto-enabled variant — no IPsec / TLS inline crypto. For crypto-enabled SKUs, see MCX621102AC-ADAT.
NOT a Multi-Host or socket-direct card — standard single-host PCIe NIC.
NOT supplied with transceivers, SFP28 DAC cables, or low-profile brackets — sold standalone, tall bracket only.

Compatibility & Constraints

Host slot: Requires PCIe 4.0 x8 slot for full bandwidth; operates in PCIe 3.0 x8 mode at reduced throughput in Gen 3 servers.
Drivers / OS: Linux MLNX_OFED 5.x or later; Windows WinOF-2 / WinOF-2.80 or later; Inbox drivers on RHEL 8+, Ubuntu 20.04+, ESXi 7.0+. Confirm firmware support for your kernel before ordering — EOL status applies.
Switch pairing: Any SFP28-compliant 25GbE switch — typical heads include NVIDIA Spectrum-2 SN2410 (48× SFP28 + 8× QSFP28), Spectrum-2 SN2100 in breakout, Spectrum-3 SN4600C / SN4410, Cisco Nexus 93180YC-FX3, Arista 7050SX3.
Cabling: Passive SFP28 DAC (0.5–5 m) for intra-rack; active SFP28 AOC (3–30 m) for inter-rack within a row; 25GBASE-SR optical transceivers (e.g. MMA2P00-AS) over OM3/OM4 MMF for longer runs.
Bracket: Tall bracket factory-assembled. Low-profile bracket must be sourced separately if required.
EOL: NVIDIA end-of-life — firmware and software support verification is the buyer's responsibility.

Frequently Asked Questions
Q. What is the MCX621102AN-ADAT?
ConnectX-6 Dx EN NIC: dual 25GbE SFP28, PCIe 4.0 x8, No Crypto, Tall Bracket.
Q. How does MCX621102AN-ADAT differ from MCX623105AN-CDAT?
MCX621102AN = dual 25GbE SFP28 / PCIe4 x8. MCX623105AN = single 100GbE QSFP56 / PCIe4 x16.
Q. Is MCX621102AN-ADAT InfiniBand capable?
No — Ethernet EN only. For VPI, see MCX653/MCX654 series.
Q. What offloads does MCX621102AN-ADAT support?
RoCE v2, NVMe-oF, VXLAN/NVGRE, SR-IOV.
Q. What condition does T.E.S IT-SOLUTIONS supply?
Refurbished Grade A — EEPROM-verified, link-tested, cosmetically inspected, EU stock.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS is a Europe-based NVIDIA Mellanox specialist serving HPC, AI, cloud, and enterprise data-center procurement teams since 2007. Every refurbished ConnectX adapter is identified by MPN, NVIDIA P/N, and ASIC generation, link-tested where topology is available, and packed in ESD-safe anti-static packaging. Multi-currency B2B invoicing, EU stock with worldwide express options, direct technical contact with our engineering team — no call-centers. Free pre-sale switch / adapter / cable pairing advice included.
Product Range
T.E.S IT-SOLUTIONS carries the full ConnectX-6 Dx EN portfolio including MCX621 (PCIe 4.0 x8) and MCX623 (PCIe 4.0 x16) variants in 25GbE, 50GbE, 100GbE, and 200GbE configurations, plus the MCX631 ConnectX-6 Lx entry-level 25/50GbE family. Contact us for current stock, crypto-enabled SKUs (AC suffix), low-profile brackets, or alternative configurations.
Quality Assurance
All refurbished NVIDIA Mellanox adapter cards supplied by T.E.S IT-SOLUTIONS are inspected for physical condition, MPN verification, bracket integrity, EEPROM / vendor data, and connector/port condition. Units are link-tested where bench topology permits and packed individually in ESD-safe anti-static packaging.