Dell 0DN78C — Mellanox ConnectX-6 Lx Dual-Port 25GbE SFP28 OCP 3.0 Adapter (Refurbished)
Technical Identity
The Dell 0DN78C is a Dell OEM rebrand of the NVIDIA Mellanox ConnectX-6 Lx EN Ethernet network adapter in the OCP 3.0 SFF (Small Form Factor) mezzanine form factor. It delivers two 25GbE SFP28 ports for Dell PowerEdge servers, with hardware offloads for RoCE v2, NVMe-oF, SR-IOV, and ASAP² accelerated switching. Lx-class ASIC: Ethernet only — no InfiniBand. Condition: Refurbished, bench-verified Grade A.
Specifications
Brand / OEM: Dell (rebrand of NVIDIA Mellanox ConnectX-6 Lx EN)
Dell P/N: 0DN78C
ASIC: ConnectX-6 Lx (Ethernet-only Lx variant)
Ports: 2× 25GbE SFP28
Form factor: OCP 3.0 SFF mezzanine (NOT PCIe add-in card)
Host interface: PCIe Gen 4.0 x8
Protocol: Ethernet only (Lx ASIC — no InfiniBand support)
Speeds supported: 1 / 10 / 25 GbE per port
Hardware offloads: RoCE v2, NVMe-oF, SR-IOV, ASAP² Open vSwitch (OVS) acceleration, GPUDirect over Ethernet, VXLAN / GENEVE / NVGRE encap-decap
Qualification: Dell PowerEdge validated (Dell firmware track)
Condition: Refurbished — Grade A, EEPROM verified, link tested, cosmetically inspected
What This Is NOT
NOT a PCIe add-in card. 0DN78C is OCP 3.0 SFF mezzanine — it requires an OCP 3.0 slot in the server chassis. For the PCIe add-in equivalent on Dell, see 0R5WK9 (also ConnectX-6 Lx 2× 25GbE SFP28, PCIe Gen 4.0 x8).
NOT InfiniBand. ConnectX-6 Lx is Ethernet-only. For InfiniBand HDR/EDR + Ethernet VPI, you need ConnectX-6 Dx or ConnectX-6 VPI (different ASIC).
NOT 100GbE. Per-port maximum is 25GbE on SFP28. For 100GbE-class workloads, see ConnectX-6 Dx (QSFP56).
NOT a standard NVIDIA-branded retail card. This is a Dell OEM unit with Dell firmware. Verify firmware compatibility outside Dell PowerEdge before deploying in a third-party chassis.
NOT shipped with SFP28 transceivers, DAC, AOC cables, or rail kits — adapter only.
Compatibility & Constraints
Server slot: OCP 3.0 SFF slot required. Common in Dell PowerEdge R650 / R750 / R7515 / R7525 / R660 / R760 generations — verify the chassis SKU includes the OCP 3.0 mezzanine bay before ordering.
Cabling: Pair with NVIDIA / Mellanox 25GbE SFP28 DAC (e.g. MCP2M00-A001 1m, MCP2M00-A003 3m) for intra-rack, or SFP28 AOC (MFA2P10-A003 / -A005 / -A010) for inter-rack runs up to 30m. Third-party 25G SFP28 transceivers and Cisco / Arista coded DACs are interoperable in EN mode.
Switch side: Works with any 25GbE SFP28 ToR — typical pairings include NVIDIA Spectrum-2 SN3700-CS / SN3420, Cisco Nexus 93180YC-FX, Arista 7060CX, Dell PowerSwitch S5212F-ON. The adapter does NOT belong in the Quantum / Spectrum / Cisco-Switches category — it pairs with them.
Firmware / driver: Dell DUP for 0DN78C; in-box drivers in RHEL 8.4+, SLES 15 SP3+, Ubuntu 20.04+, ESXi 7.0 U3+, Windows Server 2019/2022. RoCE v2 requires DCB / PFC on the switch fabric.
Power / thermal: ≤14W typical — covered by Dell PowerEdge baseline OCP 3.0 thermal envelope.
Frequently Asked Questions (FAQ)
Q. What is the Dell 0DN78C and what is the underlying NVIDIA part?
0DN78C is Dell's OEM rebrand of the NVIDIA Mellanox ConnectX-6 Lx EN, OCP 3.0 SFF, dual-port 25GbE SFP28, PCIe Gen 4.0 x8 — the equivalent NVIDIA marketing PN is MCX631432AS-ADAB / MCX631432AN-ADAB class. It carries Dell firmware and is qualified for Dell PowerEdge.
Q. How does the 0DN78C (OCP 3.0) differ from 0R5WK9 (PCIe)?
Same ASIC (ConnectX-6 Lx), same dual 25GbE SFP28 ports, same PCIe Gen 4.0 x8 host link. The only difference is the form factor: 0DN78C is OCP 3.0 SFF mezzanine and slots into the OCP bay; 0R5WK9 is a standard half-height PCIe add-in card that occupies a PCIe x8 / x16 slot. Pick the form factor that matches the chassis layout.
Q. Does the 0DN78C support InfiniBand?
No. The ConnectX-6 Lx ASIC is Ethernet only. For InfiniBand HDR/EDR or VPI dual-protocol, you need ConnectX-6 Dx (Ethernet up to 200GbE) or ConnectX-6 VPI (HDR + 200GbE) — different ASIC, different SKU.
Q. Which SFP28 DAC / AOC cables are recommended?
For intra-rack ≤3m: NVIDIA / Mellanox MCP2M00-A001 (1m), MCP2M00-A002 (2m), MCP2M00-A003 (3m) passive copper DAC. For inter-rack 5–30m: MFA2P10-A005 (5m), MFA2P10-A010 (10m), MFA2P10-A030 (30m) SFP28 AOC. Third-party 25G SFP28 optics also interoperate.
Q. What condition does T.E.S IT-SOLUTIONS supply?
Refurbished Grade A — every unit is EEPROM-verified, link-tested in a 25GbE topology, cosmetically inspected, and shipped from our EU warehouse with anti-static packaging. Free pre-sale compatibility consultation included.
Why buy from T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS is a Europe-based NVIDIA Mellanox and data-center networking specialist serving HPC, AI, and enterprise procurement teams since 2007. Every adapter is identified by MPN, ASIC generation, and firmware track before it ships, and every customer gets free pre-sale compatibility advice for switch / adapter / cable pairing. Multi-currency B2B invoicing, EU stock with worldwide express options, and direct technical contact with our engineering team — not a call-center.