Arista CAB-D-D-400G-2M | 400G QSFP-DD to QSFP-DD DAC Twinax Cable, 2m

Q: What is the difference between this DAC cable and an active optical cable (AOC) for 400G connections?
A: This CAB-D-D-400G-2M is a passive Direct Attach Copper (DAC) Twinax cable, meaning it has no active electronic components and uses copper conductors for signal transmission. DAC cables are ideal for short-reach connections (typically up to 3–5 metres), offering lower latency, lower power consumption, and lower cost compared to active optical cables (AOCs). AOCs use fibre optic transmission with active electronics at each end, making them better suited for longer reaches. For rack-to-rack or top-of-rack connections within 2 metres, this passive DAC is the optimal choice.

Q: Which Arista switches are compatible with the CAB-D-D-400G-2M?
A: This cable is compatible with Arista switches that feature QSFP-DD 400G ports, including the 7050X4, 7060X4, 7300X3, and 7800R3 series. It is also broadly compatible with any third-party switch or network adapter that supports the QSFP-DD MSA standard and 400GBASE-CR8, provided the vendor allows third-party DAC cables.

Q: Can the CAB-D-D-400G-2M be used to break out into multiple lower-speed connections?
A: No. This cable is a point-to-point 400G QSFP-DD to QSFP-DD assembly and does not support breakout. If you require breakout configurations — for example, 2x 200G or 8x 50G — you would need a dedicated 400G breakout cable with appropriate connectors on each end (e.g., QSFP-DD to 2x QSFP56 or QSFP-DD to 8x SFP56).

Q: What is the maximum supported cable length for this 400GBASE-CR8 passive DAC?
A: This specific cable is 2 metres in length. Passive DAC Twinax cables at 400G typically support reaches of up to 3–5 metres depending on the platform. For distances beyond this, active optical cables (AOCs) or 400G QSFP-DD optical transceivers with fibre cabling should be considered.

Q: Can I buy this cable in Australia and how quickly can I receive it?
A: Yes. The Arista CAB-D-D-400G-2M is available to purchase directly from iptrading.com.au. IP Trading is a specialist B2B IT hardware reseller serving Australian businesses with fast shipping and expert pre-sales support. Contact the team for stock availability, volume pricing, and lead times.

Q: Does this cable require any configuration or drivers to operate?
A: No driver or configuration is required. As a passive copper DAC cable, it is plug-and-play once inserted into compatible QSFP-DD ports. The Arista EOS operating system automatically detects and identifies the cable, simplifying deployment in high-density data centre environments.