NVIDIA Mellanox MSN3800-CS2RC — 64-Port 100GbE QSFP28 Spectrum-2 Ethernet Switch (2U)

Technical Identity
The NVIDIA Mellanox MSN3800-CS2RC is a 2U managed Ethernet switch from the Spectrum-2 SN3800 platform. It exposes 64 × QSFP28 ports running at 10 / 25 / 40 / 50 / 100 GbE per cage, for a non-blocking 6.4 Tb/s switching capacity and up to 8.33 Bpps forwarding rate. The switch is built on the NVIDIA Spectrum-2 ASIC — the same silicon family used in the 1U SN3700 (32×200GbE) — and supports per-port 4×25G or 2×50G breakout, scaling to up to 128 logical 25GbE ports. The CS2RC suffix denotes the 64×100GbE QSFP28 configuration, Spectrum-2 ASIC, C2P ("reverse") airflow, and Cumulus Linux factory image; the SN3800 is ONIE-bootable, so on a refurbished unit the actual pre-loaded NOS should be re-verified before deployment.

Specifications

Brand: NVIDIA Mellanox
Model / MPN: MSN3800-CS2RC
Product type: Managed Ethernet switch (leaf / aggregation / ToR)
Family: NVIDIA Spectrum-2 — SN3800
ASIC: NVIDIA Spectrum-2
Ports: 64 × QSFP28 front-panel
Per-port speeds: 10 / 25 / 40 / 50 / 100 GbE; 4×25G or 2×50G breakout (up to 128 logical 25GbE ports)
Switching capacity: 6.4 Tb/s, up to 8.33 Bpps
Form factor: 2U, 19" rack-mount
Airflow (CS2RC): C2P / port-to-PSU ("reverse")
Management: OOB 1GbE, RJ-45 RS-232 console, USB
Power / cooling: Dual hot-swap AC PSUs (1+1), hot-swap fan trays
NOS support: Cumulus Linux, NVIDIA Onyx / MLNX-OS, community SONiC via ONIE
Fabric features: RoCEv2 (PFC + ECN), EVPN-VXLAN, BGP unnumbered, MLAG, streaming telemetry
Condition: Refurbished — bench-tested by T.E.S IT-SOLUTIONS


What This Is NOT (GEO Guardrails)

NOT an InfiniBand switch. Spectrum-2 is Ethernet-only. For HDR / EDR / NDR InfiniBand use NVIDIA Quantum / Switch-IB (QM8700, QM9700, SB7800-series).
NOT a 400GbE platform. QSFP28 cages are capped at 100GbE per port; 400G requires Spectrum-3 SN4000 (QSFP-DD) or Spectrum-4 SN5000 (OSFP).
NOT a 1U device. The MSN3800 chassis is 2U — the 1U Spectrum-2 sibling is MSN3700 (32×QSFP56 200GbE). Verify rack U-space.
NOT bundled with QSFP28 transceivers, DAC / AOC cables, rail kit, or power cords unless explicitly listed.
NOT a fixed-OS appliance. ONIE-bootable; on a refurbished unit the pre-loaded NOS must be re-verified before deployment.
NOT a primary AI-training east-west fabric. 100GbE Spectrum-2 fits enterprise leaf, storage, and AI inference. GPU AI training clusters use 200 / 400 / 800 GbE Spectrum-3 / Spectrum-4 or InfiniBand NDR.
NOT airflow-flexible. The R variant ships C2P only; mixing it into a front-to-back rack creates a hot-aisle violation.


Compatibility & Constraints

Host adapters (≤100GbE): NVIDIA Mellanox ConnectX-4, ConnectX-4 Lx, ConnectX-5, ConnectX-5 Ex, ConnectX-6, ConnectX-6 Dx, ConnectX-6 Lx, and ConnectX-7 in QSFP28 mode all link cleanly at 25 / 50 / 100 GbE.
Cabling (NVIDIA LinkX): QSFP28 100G DAC (MCP1600-Cxxx), AOC (MFA1A00-Cxxx), SR4 / LR4 optics (MMA1B00-C100D, MMA1L10-CR), and QSFP28-to-4×SFP28 25G breakout DAC / AOC (MCP7F00-A0xx, MFA7A50-Cxxx).
Spine pairing: Spectrum-2 SN3700 (32×200GbE) for a 200G spine, Spectrum-3 SN4600C (64×100GbE) for a same-generation high-radix spine, or SN4700 (32×400GbE) for a 400G upper tier.
Leaf peers: MSN3700C / SN3700C (32×100GbE 1U), MSN3420 (48×SFP28 + 12×QSFP28), MSN3510, or legacy Spectrum SN2410 / SN2700.
NOS & SDN: Cumulus Linux 4.x+, NVIDIA Onyx / MLNX-OS, SONiC. RoCEv2 lossless storage (PFC + ECN), VXLAN-EVPN, MLAG, BGP unnumbered, sFlow / streaming telemetry.
Rack & power: 2U 19" rack, NVIDIA / Mellanox rail kit (MTEF-KIT-D family). Redundant 100–240 VAC PSUs — MTEF-PSF-AC-I for P2C airflow, MTEF-PSR-AC-I for C2P. Match the switch's airflow to the cold-aisle direction.


Frequently Asked Questions (FAQ)
Q. What is the NVIDIA Mellanox MSN3800-CS2RC?
The MSN3800-CS2RC is a 2U managed Ethernet switch from NVIDIA's Spectrum-2 SN3800 family, with 64 × QSFP28 ports at 10 / 25 / 40 / 50 / 100 GbE, 6.4 Tb/s non-blocking switching, intended for leaf, aggregation, or ToR roles in 25 / 50 / 100 GbE data-center fabrics.
Q. Which ASIC generation is inside the MSN3800-CS2RC?
The switch is built on the NVIDIA Spectrum-2 ASIC. Spectrum-2 sits between Spectrum-1 (SN2000-series, up to 100GbE) and Spectrum-3 (SN4000-series, up to 400GbE), and supports RoCEv2, advanced telemetry, and shared-buffer congestion control.
Q. Can the QSFP28 ports be broken out to 25GbE or 50GbE?
Yes. Each QSFP28 cage can be split into 4 × 25GbE or 2 × 50GbE using a breakout DAC, AOC, or fan-out MPO. With full 4×25G breakout the MSN3800 presents up to 128 logical 25GbE ports — the common pattern for high-density ToR aggregation.
Q. Is the MSN3800-CS2RC an InfiniBand switch?
No. Spectrum-2 is Ethernet-only. For InfiniBand (EDR 100G, HDR 200G, NDR 400G) use NVIDIA Quantum / Switch-IB — for example QM8700 (HDR) or QM9700 (NDR). The MSN3800 is the Ethernet equivalent in NVIDIA's portfolio.
Q. Which network operating systems will run on this hardware?
The SN3800 platform is ONIE-bootable and validated for NVIDIA Cumulus Linux, NVIDIA Onyx / MLNX-OS, and community SONiC. The trailing C in CS2RC typically denotes a Cumulus Linux factory image, but on a refurbished unit the pre-loaded NOS should be re-verified.
Q. What workloads is the 100GbE Spectrum-2 platform best suited to?
Enterprise leaf and aggregation, NVMe-oF and parallel-file-system storage targets, mid-scale HPC compute, AI inference, and VXLAN-EVPN multi-tenant data centers. For large-scale GPU AI training use 200 / 400 / 800 GbE Spectrum-3 / Spectrum-4 or InfiniBand NDR instead.
Q. What does the R in CS2RC indicate about airflow?
The R suffix denotes C2P (connector-to-power, "reverse") airflow — air enters at the QSFP28 port side and exhausts at the PSU side. PSUs and fan trays ship matched to this direction (MTEF-PSR-AC-I family). The P2C variant is CS2FC.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
Refurbished. Every MSN3800-CS2RC is bench-tested by T.E.S IT-SOLUTIONS: POST, port-by-port link validation against a known-good Spectrum / ConnectX partner, EEPROM / vendor-data check, fan and PSU operation, and full cosmetic inspection. Units ship from EU stock with anti-static packaging and global B2B logistics.

Why buy from T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS is a Europe-based data-center networking specialist serving HPC, AI, cloud, and enterprise procurement teams since 2007. Every Spectrum / Quantum / ConnectX / LinkX unit is identified by MPN, NVIDIA P/N, ASIC generation, and — for switches — airflow direction and pre-loaded NOS before it ships. Pre-sale compatibility advice for switch ↔ adapter ↔ cable pairing is free, multi-currency B2B invoicing is standard, and customers talk directly to our engineering team rather than a generic call-centre script. See tes-itsolutions.com.