What Is a 100GbE Switch?
A 100GbE (100 Gigabit Ethernet) switch is a datacenter network switch that provides 100 Gbps of bandwidth per port, enabling high-throughput, low-latency connectivity between servers, storage arrays, and compute nodes. 100GbE switches are built on specialized ASICs (such as NVIDIA Spectrum-1/Spectrum-2/Spectrum-3) that deliver cut-through latency under 300 nanoseconds and shared packet buffers of 12–64 MB for lossless RDMA transport.
In modern datacenter architectures, 100GbE switches serve as spine or leaf nodes in Clos topologies, connecting GPU clusters for AI training, NVMe-oF storage fabrics, and HPC interconnects where zero packet loss and sub-microsecond latency are non-negotiable.
100GbE Switch Specifications Comparison
| Specification | SN2700 | SN3700 | SN3800 | SN4600 |
|---|---|---|---|---|
| ASIC | Spectrum-1 | Spectrum-2 | Spectrum-3 | Spectrum-2 |
| 100G Ports | 32 | 36 | 64 | 36 |
| Throughput | 6.4 Tbps | 7.2 Tbps | 12.8 Tbps | 7.2 Tbps |
| Latency | <300 ns | <250 ns | <250 ns | <250 ns |
| Buffer | 12 MB | 16 MB | 64 MB | 16 MB |
| 200G Support | No | 4 ports | 36 ports | No |
| RoCE v2 | Yes | Yes | Yes | Yes |
| OS | MLNX-OS / Cumulus | MLNX-OS / Cumulus / SONiC | Cumulus / SONiC | MLNX-OS / Cumulus / SONiC |
| Use Case | HPC / Trading | AI/ML / Storage | Cloud Spine | Edge / Outdoor |
How to Choose a 100GbE Switch
- HPC & financial trading → SN2700 (lowest cost, 32 ports, proven Spectrum-1)
- AI/ML GPU clusters & NVMe-oF → SN3700 (36 ports, larger buffer, RoCE v2 optimized)
- Cloud spine (200G/400G mixed) → SN3800 (64×100G / 36×200G, Spectrum-3)
- Edge/outdoor/telecom → SN4600 (same ASIC as SN3700, -40°C to 55°C)
Frequently Asked Questions
What does 100GbE mean?
100GbE stands for 100 Gigabit Ethernet—a IEEE 802.3bj standard providing 100 Gbps of bandwidth per port using QSFP28 connectors. Each 100G port can be split into 2×50G or 4×25G using breakout cables.
Can 100GbE ports be split into slower speeds?
Yes. Each QSFP28 100GbE port supports fan-out: 1×100G, 2×50G, or 4×25G using breakout cables. A 36-port SN3700 can serve up to 144×25GbE connections.
What is RoCE v2 and why does it matter?
RoCE v2 (RDMA over Converged Ethernet) enables zero-CPU-copy data transfer over Ethernet with PFC (Priority Flow Control) and ECN (Explicit Congestion Notification) for lossless transport. It's critical for GPU-to-GPU communication in AI training clusters.
Is a refurbished 100GbE switch reliable?
Yes. Mellanox/NVIDIA switches have no moving parts (SSD storage, passive cooling fans), and refurbished units undergo full functional testing, firmware updates, and port verification. Mean time between failures exceeds 500,000 hours.
Shop 100GbE switches at Zhongxin Data — enterprise network hardware specialists. Worldwide shipping from Hong Kong.