Mellanox SN3700-CS2FC 100GbE 32-Port QSFP28 Switch Cumulus Used
Quick answer: Mellanox SN3700-CS2FC used, bench-tested. NVIDIA Spectrum-2 SN3700C with 32 QSFP28 ports at 100GbE, 3.2 Tb/s switching capacity (non-blocking), 425 ns latency, 42 MB buffer, 1U and P2C airflow — with Cumulus Linux preloaded.
In stock: SN3700-CS2FC is in stock — availability is confirmed per part number, so send the exact model you need and we check the shelf before quoting.
Need a quote? Message WhatsApp +86 13068616914 with the part number (for example SN3700-CS2FC) and the quantity — we reply with price, condition notes and photos of the actual unit. No price is listed here because every order is quoted per part number.
Mellanox SN3700-CS2FC
The NVIDIA Spectrum-2 SN3700C (CS2FC) is the 100GbE build of the SN3700 chassis: 32 QSFP28 ports, 3.2 Tb/s switching capacity (32 × 100GbE, non-blocking), 4.76 Bpps, 425 ns latency and a 42 MB shared buffer. It keeps the newer Spectrum-2 ASIC and deeper buffer while keeping every port at 100G, which is what most 25G/100G racks actually need.
Condition: Used — cleaned, re-flashed and bench-tested on our own test line before it is listed. 90-day warranty from delivery.
| Specification | Details |
|---|---|
| Part number | SN3700-CS2FC |
| Family | Mellanox |
| Switch silicon | NVIDIA Spectrum-2 |
| Ports | 32 × 100GbE QSFP28 |
| Port speed | 100GbE per port (50/40/25GbE with breakouts) |
| Connectors | QSFP28 (32 ports) |
| Switching capacity | 3.2 Tb/s switching capacity (32 × 100GbE, non-blocking) |
| Packet rate | 4.76 Bpps |
| Latency | 425 ns |
| Packet buffer | 42 MB shared packet buffer |
| Airflow | P2C — power-to-connector (front-to-back) |
| Form factor | 1U rackmount, standard depth |
| Dimensions | 44 × 428 × 559 mm |
| Power | 2 × hot-swap AC PSU (1+1), 4 × hot-swap fans |
| Management | x86 dual-core control plane, 8 GB RAM, 32 GB SSD |
| Software | NVIDIA Cumulus Linux |
Key features
- 32 × 100GbE QSFP28 ports
- 3.2 Tb/s switching capacity (32 × 100GbE, non-blocking), 4.76 Bpps
- 425 ns latency, 42 MB buffer
- Breakout to 4 × 25GbE or 2 × 50GbE
- Cumulus Linux preloaded
- RoCEv2 with PFC and ECN
Typical deployments
100G leaf and spine layers, 25G server aggregation, storage fabrics, and EVPN-VXLAN overlays managed through Cumulus.
What is included
- Switch chassis with both power supplies
- Fan units (P2C)
- Rail kit
- Condition report and bench-test notes
Not included
- QSFP28 optics and cables
- Cumulus licence transfer paperwork
SN3700-CS2FC in the lineup
The C in CS2FC is the 100GbE port class, not a different chassis — SN3700C and SN3700 share the 1U body and 42 MB buffer. If part of the rack is moving to 200G, buy the VS2FC and run 100G through breakouts instead.
How it compares with models we also stock
| Model | Fabric | Ports | Best for |
|---|---|---|---|
| SN3700-CS2FC (this page) | Ethernet 100G | 32 QSFP28 | 100G leaf with Cumulus |
| SN3700-VS2FC | Ethernet 200G | 32 QSFP56 | 200G leaf, 100G via breakout |
| SN2700-CS2FC | Ethernet 100G | 32 QSFP28 | Older Spectrum-1 ASIC, 12 MB buffer, Cumulus |
| SN3700-CS2F | Ethernet 100G | 32 QSFP28 | Same chassis on Onyx |
| SN3800-CS2RO | Ethernet 100G | 64 QSFP28 | Double the ports, 2U |
Why buy this switch from Zhongxin Data
- Bench-tested on our own in-house test line — ports, fans and power supplies are checked before the unit leaves.
- We quote only what we can physically confirm: the exact part number, airflow direction and condition notes come from the unit in front of us.
- Used enterprise switches at secondary-market pricing, with a 90-day warranty from delivery.
- Worldwide shipping from Hong Kong, China; consolidation with servers, NICs and optics from the same rack is routine.
Request a quote
Send the part number SN3700-CS2FC, the quantity you need and your destination to WhatsApp +86 13068616914 (or reply to any thread on zhongxindata.hk). We confirm availability against the exact model before quoting, and we can quote alternative airflow builds or port-count variants from the same family if they fit your rack better.
Frequently asked questions
How many ports does the SN3700 have?
32 QSFP28 ports at 100GbE each — expandable to 128 × 25GbE with breakouts. The 36-port 100GbE figure belongs to the SB7700 EDR InfiniBand switch, a different platform.
What speed can each port run?
100GbE native, or 2 × 50GbE / 4 × 25GbE with breakouts — the 100GbE port class of the SN3700 family. For native 200G ports, take the VS2F/VS2RC build.
Which network OS is on it?
This CS2FC build comes with Cumulus Linux preloaded. The Onyx build is the CS2F and the ONIE-only build is the CS2FO.
Does it support RoCEv2?
Yes, with PFC and ECN, and the 42 MB shared buffer absorbs bursts better than the 12 MB buffer of the older SN2700.
Is this InfiniBand?
No. It is Ethernet. For native InfiniBand at 100G the SB7700 is the matching platform; at 400G it is the Quantum-2 QM9700/QM9790.
What warranty do you provide?
90-day warranty from delivery, after bench testing on our own line.
Available at Zhongxin Data — enterprise network hardware specialists. Worldwide shipping from Hong Kong, China.
Product image is a reference image for the form factor — revision, label and airflow sticker vary by batch. Ask us for photos of the actual unit before you commit.