Arista Networks CAB-D-8S-400G-3M Compatible 400G QSFP-DD 8 x 50G PAM4 to 8 x 50G SFP56 50G PAM4 Passive Copper Breakout Cable, 3m (10ft)
The assembly listed here is the 3m (10ft) member of the CAB-D-8S-400G-3M product family for Arista Networks equipment. It provides 400G DAC connectivity through QSFP-DD to 8x SFP56. Project teams can use the detailed table, related references and documentation-oriented packing information to keep each delivered cable aligned with its planned endpoints.
OEM Part Number: CAB-D-8S-400G-3MHT Part Number: CAB-D-8S-400G-3M
Product Highlights
- Compatible alternative to Arista Networks CAB-D-8S-400G-3M
- 400G connectivity at 400Gbps
- Interface configuration: QSFP-DD to 8x SFP56
- Fixed length and part number: 3m (10ft), CAB-D-8S-400G-3M
- Cable construction: Passive Breakout DAC
- Conductor specification: 28AWG
- Maximum power consumption: 0.1W (QSFP-DD End)0.1W (SFP56 Per End)
- Minimum bend radius: 39.5mm
Specifications
| HT Part Number | CAB-D-8S-400G-3M |
|---|---|
| Arista Networks Compatible | CAB-D-8S-400G-3M |
| Manufacturer | HT |
| Form Factor | QSFP-DD to 8x SFP56 |
| Max. Data Rate | 400Gbps |
| Media | Copper |
| Cable Type | Passive Breakout DAC |
| Minimum Bend Radius | 39.5mm |
| Wire AWG | 28AWG |
| Cable Length | 3m (10ft) |
| 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.
Cable Construction and Routing
This assembly uses 28AWG conductors, PVC (OFNR) jacket, minimum bend radius 39.5mm. 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
At 3m (10ft), this assembly can bridge non-aligned ports or adjacent racks while remaining a single direct-attach link. Support longer horizontal runs with suitable cable management and preserve space for cooling and future maintenance.
Position Within the Length Range
CAB-D-8S-400G-3M is the longest of 6 verified length options in this family. Compared with CAB-D-8S-400G-2.5M at 2.5m (8ft), it provides 0.5m of additional reach for a longer vertical drop, a wider rack or an adjacent-cabinet route. Confirm that the complete path requires this length, because unused slack still needs supported, bend-safe storage.
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 28AWG; the minimum bend radius is 39.5mm; the stated power consumption is 0.1W (QSFP-DD End)0.1W (SFP56 Per End); the jacket material is PVC (OFNR).
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.
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-3M.
Are separate transceivers or patch leads required?
No. This is one complete direct-attach assembly. The ends are not detachable modules and should not be separated from the cable.
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.
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-3M associated with 3m (10ft) 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. Volume orders can include customer references on the labels and carton list.
