Arista Networks CAB-D-8S-400G-0.5M Compatible 400G QSFP-DD 8 x 50G PAM4 to 8 x 50G SFP56 50G PAM4 Passive Copper Breakout Cable, 0.5m (2ft)
For project documentation, Arista Networks CAB-D-8S-400G-0.5M and this cable’s physical length should be recorded together. The product described here is a 0.5m (2ft) DAC assembly for 400G links, using QSFP-DD to 8x SFP56. Its OEM cross-reference, HT part number, specification table and packing options support traceable ordering and installation records.
OEM Part Number: CAB-D-8S-400G-0.5MHT Part Number: CAB-D-8S-400G-0.5M
Product Highlights
- Compatible alternative to Arista Networks CAB-D-8S-400G-0.5M
- 400G connectivity at 400Gbps
- Interface configuration: QSFP-DD to 8x SFP56
- Fixed length and part number: 0.5m (2ft), CAB-D-8S-400G-0.5M
- Cable construction: Passive Breakout DAC
- Conductor specification: 30AWG
- Maximum power consumption: 0.1W (QSFP-DD End)0.1W (SFP56 Per End)
- Minimum bend radius: 33.5mm
Specifications
| HT Part Number | CAB-D-8S-400G-0.5M |
|---|---|
| Arista Networks Compatible | CAB-D-8S-400G-0.5M |
| Manufacturer | HT |
| Form Factor | QSFP-DD to 8x SFP56 |
| Max. Data Rate | 400Gbps |
| Media | Copper |
| Cable Type | Passive Breakout DAC |
| Minimum Bend Radius | 33.5mm |
| Wire AWG | 30AWG |
| Cable Length | 0.5m (2ft) |
| Jacket Material | PVC (OFNR) |
| Max. Power Consumption | 0.1W (QSFP-DD End)0.1W (SFP56 Per End) |
| Modulation Format | QSFP-DD-8x 50G-PAM4SFP56-50G-PAM4 |
| DDM/DOM | Not Supported |
| Commercial TemperatureRange | 0 to 70°C (32 to 158°F) |
| Protocols | QSFP-DD MSA, SFF-8432, IEEE 802.3bs-400GAUI-8, IEEE802.3cd-50GAUI-1, CMIS 4.0, SFF-8472 |
Signal and Lane Configuration
The listed modulation format is QSFP-DD-8x 50G-PAM4SFP56-50G-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.
Power and Thermal Planning
The rated power consumption is 0.1W (QSFP-DD End)0.1W (SFP56 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 30AWG conductors, PVC (OFNR) jacket, minimum bend radius 33.5mm. 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 determined by the host interface and protocol support. Listed interface and protocol references include QSFP-DD MSA, SFF-8432, IEEE 802.3bs-400GAUI-8, IEEE802.3cd-50GAUI-1, CMIS 4.0, SFF-8472. Confirm that the host firmware and port configuration support the same operating mode.
Breakout Port Mapping
The QSFP-DD to 8x SFP56 configuration divides the high-speed interface into multiple lower-speed connections. Verify the upstream lane assignment, downstream port speeds and breakout setting on the host before connecting the assembly. Each branch must attach to the correct remote interface.
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 0.5m (2ft) length is suited to closely aligned ports where excessive slack would obstruct airflow or complicate dressing. Measure the actual port-to-port path before choosing CAB-D-8S-400G-0.5M; even a short assembly must retain the specified bend radius and should never be pulled tight behind the equipment.
Position Within the Length Range
CAB-D-8S-400G-0.5M is the shortest of 6 verified length options in this family. It is the preferred choice when the port positions are close and cable slack must be kept to a minimum. The next option is CAB-D-8S-400G-1M at 1m (3ft), adding 0.5m for a less direct routing path; selecting it unnecessarily would leave more cable to dress.
Project Documentation and Cable Identification
Large deployments are easier to audit when the order code, physical length and endpoint record agree. Keep the OEM reference in the compatibility document and use the HT part number on the packing list. Where several lengths arrive together, labels and carton groups can be arranged by rack or port plan so installers do not have to identify cables by appearance alone. For this assembly, the listed conductor specification is 30AWG; the minimum bend radius is 33.5mm; the stated power consumption is 0.1W (QSFP-DD End)0.1W (SFP56 Per End); the jacket material is PVC (OFNR).
Arista Networks Compatibility and Factory Testing
Factory verification links the compatibility identity to the exact physical assembly described on this page. Identification, connector condition and live link behavior are checked before packing. Customers can submit equipment and firmware details with the project documentation for a more specific pre-order compatibility review. Both connectors are examined before the operating test, which includes link stability and diagnostic indications.
Frequently Asked Questions
Is this an original Arista Networks cable?
No. It is an HT-manufactured compatible alternative for equipment that specifies Arista Networks CAB-D-8S-400G-0.5M.
Can excess cable be folded into a compact bundle?
No. Use a supported, bend-safe service loop and observe the listed minimum bend radius. Do not crease the cable or tighten ties around the connector boots.
Will any matching connector operate at the same speed?
Not necessarily. Both hosts must support the stated rate, identification, lane mapping and any required breakout configuration; mechanical compatibility alone is insufficient.
What details assist a compatibility review?
Provide the equipment manufacturer, model, port type, hardware revision and software release, together with the OEM reference, required length and quantity.
Ordering Information
Use the listed HT part number for ordering and retain the OEM reference as the host-compatibility cross-reference. Send quantities by length, along with any rack-based packing or label instructions. If the project has mixed equipment, include the host model for each group rather than relying only on the aggregate cable rate. Keep CAB-D-8S-400G-0.5M associated with 0.5m (2ft) throughout the order and receiving record.
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. Worldwide courier services are available, with air or sea freight for consolidated shipments; freight-collect delivery and coordination with a customer’s logistics provider can be arranged.
Quality Assurance and Packaging
Inspection and link testing are completed before the cable enters its protective packaging. Project orders can be packed and labelled by length, rack or customer reference, with packing documentation that makes received quantities straightforward to reconcile against the installation schedule. Standard protective packing is used by default, with project documentation arranged when requested.
