Question 1

What is the difference between DAC and AOC Mellanox cables?

Accepted Answer

Direct Attach Copper (DAC) cables, like MCP1650-V003, are low-cost and ideal for short runs (up to 5m) within a rack. Active Optical Cables (AOCs), such as MFS1S00-H015E, are lightweight, EMI-resistant, and designed for longer distances (up to 150m).

Question 2

Which Mellanox cable should I use for 200Gb/s HDR InfiniBand?

Accepted Answer

For HDR 200Gb/s, TES-IT supplies QSFP56 DACs for short rack-to-rack connections and QSFP56 AOCs for longer spans. A popular choice is MFS1S00-HxxxE for long runs, paired with MCX653106A-HDAT ConnectX-6 NICs and MQM8700-HS2F Quantum switches.

Question 3

Can I mix DAC and AOC cables in the same Mellanox cluster?

Accepted Answer

Yes. Many data centers use DAC cables (e.g., MCP7F00-A002R30) for short in-rack connections and AOCs (e.g., MFA7A20-C010) for inter-row or long-distance links. Both work seamlessly together in Mellanox-based infrastructures.

Question 4

Can Mellanox cables support both Ethernet and InfiniBand?

Accepted Answer

Yes, Mellanox QSFP28 and QSFP56 DAC/AOC cables are protocol-agnostic, supporting both Ethernet and InfiniBand, depending on how the NIC and switch ports are configured. This versatility makes them ideal for mixed environments.

Question 5

How does TES-IT test refurbished Mellanox cables before shipping?

Accepted Answer

Every cable undergoes signal integrity testing, throughput validation, and port compatibility checks with Spectrum switches and ConnectX NICs. Only certified cables are shipped, ensuring reliable 100–200Gb/s connectivity.

Question 6

Can TES-IT ship cables together with NICs and switches as a complete solution?

Accepted Answer

Absolutely. TES-IT supplies complete bundles including NICs, Spectrum/Quantum switches, and matching DAC/AOC cables. This ensures correct compatibility, immediate deployment, and same-day global shipping.

Question 7

Which Mellanox cables are best for GPU clusters in AI and HPC environments?

Accepted Answer

For GPU clusters requiring high-bandwidth all-to-all communication, TES-IT recommends QSFP56 HDR DACs for short intra-rack connections and QSFP56 AOCs (MFS1S00-HxxxE series) for inter-row or inter-room links. These provide 200 Gb/s throughput with ultra-low latency, making them ideal for all-reduce operations in AI training.

Question 8

Do Mellanox cables support scaling HPC clusters as we add more GPU nodes?

Accepted Answer

Yes. Mellanox cables are designed for linear scalability. Universities and HPC centers often start with DACs inside a single rack, then expand with AOCs or MPO/MTP fiber when clusters grow to multiple racks or data halls. TES-IT supplies both types, ensuring seamless cluster expansion.

Question 9

Are refurbished Mellanox cables reliable for enterprise and cloud data centers?

Accepted Answer

Absolutely. TES-IT refurbished cables are signal-tested at full rated speed (100 GbE / 200 Gb/s InfiniBand) and certified with Mellanox Spectrum switches and ConnectX NICs. Many enterprise IT departments choose refurbished cables because they deliver OEM performance at up to 70% lower cost, with same-day availability.

Question 10

What is the recommended cable mix for cloud providers building 200 Gb/s fabrics?

Accepted Answer

Cloud providers typically use:
 • DACs (MCP1650 series) for ToR (Top-of-Rack) and short-range connections
 • AOCs (MFS1S00-HxxxE) for row-to-row or long-range connectivity
 • QSFP28 to QSFP56 breakouts for mixed environments
 TES-IT can pre-bundle these with NICs and switches for faster deployment.

Question 11

How do Mellanox cables help reduce latency in financial and enterprise applications?

Accepted Answer

Low-latency industries (like fintech) use short passive DACs (e.g., MCP7F00-A002R30) to minimize serialization delay. These provide the fastest path between servers and switches, which is crucial for high-frequency trading and enterprise workloads that demand deterministic latency.

Question 12

Can Mellanox cables handle both current workloads and future scalability (NDR / 400 Gb/s)?

Accepted Answer

Yes. Current QSFP56 HDR cables support 200 Gb/s, and TES-IT also supplies OSFP and QSFP112 cables for next-generation 400 Gb/s NDR fabrics. This ensures HPC centers and cloud providers can future-proof infrastructure without major redesigns.

Question 13

Do universities and research centers get support choosing the right cables?

Accepted Answer

Yes. TES-IT provides compatibility consulting for academic HPC clusters. We guide IT teams in selecting the right mix of DACs, AOCs, and fiber for their budget, rack layout, and research workloads. Our pre-tested bundles reduce integration time and prevent costly mistakes.

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