NVIDIA Mellanox MSN3420-CB2FO Half-Width 1U Open Ethernet Switch, 48x SFP28 25GbE + 12x QSFP28 100GbE, ONIE-Only: This is a Spectrum-2 based half-width 1U fixed-configuration top-of-rack Ethernet switch with 48 SFP28 ports (10/25GbE) and 12 QSFP28 ports (40/100GbE, breakout-capable to 4x 25GbE). The 'F' suffix denotes P2C (port-to-power) airflow direction, and the 'O' suffix denotes an ONIE-only SKU — the unit ships without a pre-installed network operating system. This is a refurbished unit.
Engineering Context
The MSN3420 is built on the NVIDIA Spectrum-2 ASIC and delivers 4.8 Tbps of non-blocking switching capacity with sub-300ns port-to-port latency. The 48 SFP28 access ports support 1/10/25GbE while the 12 QSFP28 uplinks support 40/100GbE and split into 4x 25GbE per port via breakout cables, yielding up to 96 effective 25GbE downlinks. The half-width 1U chassis allows two units to be deployed side-by-side in a single rack U with shared cable management. P2C airflow draws cool aisle air from the port side and exhausts at the PSU side. Dual hot-swap AC PSUs (1+1 redundant) and N+1 hot-swap fans.
Deployment & Use Cases
25GbE top-of-rack access for hyperconverged infrastructure (Nutanix, VMware vSAN, Azure Stack HCI). Storage-fabric leaf for NVMe-oF/RoCE clusters with 100GbE spine uplinks. Edge aggregation in colocation cages where two half-width switches replace one full-width unit. AI inferencing pods with mixed 25GbE compute and 100GbE GPU server uplinks. Service provider edge with disaggregated SONiC or Cumulus Linux installs.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MSN3420-CB2FO
ASIC: NVIDIA Spectrum-2
Form Factor: Half-width 1U fixed-configuration
Ports: 48x SFP28 (10/25GbE) + 12x QSFP28 (40/100GbE)
Switching Capacity: 4.8 Tbps
Port-to-Port Latency: <300ns
Breakout: 12x QSFP28 supports 4x 25GbE split (up to 96 total 25GbE)
CPU: x86 (Intel)
PSUs: 2x AC, hot-swap, 1+1 redundant
Airflow: P2C (port-to-power)
Operating System: ONIE-only (Onyx, Cumulus Linux, SONiC sold/installed separately)
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
Compatible with NVIDIA ConnectX-4 Lx, ConnectX-5, ConnectX-6 Dx and Bluefield DPUs at 10/25/100GbE Ethernet, plus standard third-party SFP28/QSFP28 transceivers and DACs/AOCs. The 'O' SKU ships without a pre-installed OS — Onyx, Cumulus Linux, or SONiC must be installed via ONIE before deployment. P2C airflow does not match equipment designed for C2P reverse airflow; verify rack cooling direction before installation. Not an InfiniBand switch — Ethernet only. Rail kit not included; order separately.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS power-tests and port-validates every switch before shipment, including PSU redundancy and fan health checks. We provide expert consultation on Spectrum-based fabric design, ONIE-OS provisioning, and global shipping with 1–3 day handling. Visit tes-itsolutions.com for the full inventory.