Arista Networks CAB-D-D-400G-2.5M Compatible 400G QSFP-DD 8 x 50G PAM4 Passive Copper Twinax Cable, 2.5m (8ft)

Product Highlights

• Compatible alternative to Arista Networks CAB-D-D-400G-2.5M
• 400G connectivity at 400Gbps
• Interface configuration: QSFP-DD to QSFP-DD
• Fixed length and part number: 2.5m (8ft), CAB-D-D-400G-2.5M
• Cable construction: Passive Twinax
• Conductor specification: 26AWG
• Maximum power consumption: 0.1W Per End
• Minimum bend radius: 57mm

Specifications

Signal and Lane Configuration

The listed modulation format is 8x 50Gbps PAM4. Both host interfaces must be configured for the same aggregate rate and lane arrangement. A connector that fits mechanically does not by itself guarantee that the remote port supports this encoding or breakout mode.

Data-Center Design and Airflow

Select the assembly by both reach and rack layout. A direct connection removes separate module-and-patch-cord interfaces, but it still needs a bend-safe pathway and clear connector access. Keep cable bundles from blocking front-panel airflow, account for the listed interface power where applicable and choose a length that supports maintenance without leaving an unmanaged coil. For this assembly, the listed conductor specification is 26AWG; the minimum bend radius is 57mm; the stated power consumption is 0.1W Per End; the jacket material is PET.

Power and Thermal Planning

The rated power consumption is 0.1W Per End. Include this load in the host-port power and thermal budget, especially in densely populated switches. Maintain front-panel clearance and do not bundle the cable so tightly that it obstructs airflow around the connectors.

Cable Construction and Routing

This assembly uses 26AWG conductors, PET jacket, minimum bend radius 57mm. These mechanical characteristics affect how the cable should be dressed behind the equipment. Avoid sharp edges, excessive ties and repeated tight bends close to the connector boots.

Network and Protocol Considerations

The intended application is 400G Ethernet. Listed interface and protocol references include IEEE 802.3cd, QSFP-DD MSA, CMIS 4.0. Confirm that the host firmware and port configuration support the same operating mode.

Passive Copper Operation

A passive DAC has no separate optical conversion stage. Its low-power, low-latency operation is useful for short equipment links, but the assembly must remain within the length and signaling mode accepted by both hosts.

Length Selection and Installation Planning

The 2.5m (8ft) version is useful when a two-metre run would leave insufficient working slack. Before installation, check the complete horizontal and vertical path so that CAB-D-D-400G-2.5M reaches both ports without tension at either connector.

Position Within the Length Range

CAB-D-D-400G-2.5M occupies the middle of this family between CAB-D-D-400G-2M at 2m (7ft) and CAB-D-D-400G-3M at 3m (10ft). It adds 0.5m over the shorter option for extra routing clearance, while the next longer version adds another 0.5m. Measure the managed path and choose this version when its reach is sufficient without creating the slack associated with the longer assembly.

Quality Assurance and Packaging

Each cable receives connector inspection and a functional link check before it is coiled with bend-safe slack and packed. Protective materials shield the connector housings during transport. Rack or project labels are available to keep length, part number and installation destination aligned. Volume orders can include customer references on the labels and carton list.

Ordering Information

Provide the OEM reference, HT part number, fixed length and quantity, together with the intended host interfaces. Rack-based quantities and packaging instructions can be included for larger deployments. Other lengths are separate products and should be entered on their own order lines. This page’s fixed configuration is 2.5m (8ft); another length must be quoted under its corresponding part number.

Arista Networks Compatibility and Factory Testing

Compatibility confirmation combines host identification with actual link establishment and diagnostic checks. The assembly is prepared for the stated OEM reference rather than selected only by connector shape. For a new data-center deployment, the equipment model, port mode and software release provide the most useful basis for a pre-order review. Both connectors are examined before the operating test, which includes link stability and diagnostic indications.

Frequently Asked Questions

Shipping and Lead Time

Available stock is generally dispatched within one to three working days after order confirmation, with production lead times advised for larger quantities. Delivery can be arranged by courier, air freight or sea freight, and goods may instead be handed to an appointed forwarder or shipped on the customer’s courier account.