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)
For a direct equipment connection requiring Arista Networks CAB-D-8S-400G-3M, this page supplies the 3m (10ft) version with QSFP-DD to 8x SFP56. The cable supports 400G operation and eliminates a separate module-and-patch-cord assembly. Installation, maintenance and spare-cable identification are addressed alongside the full technical details.
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.
Field Installation and Maintenance
Inspect the route and both connectors before installation, then support the cable without pulling on either connector housing. During maintenance, release the latch properly rather than using the cable as a handle. Keep protection on unused ends, and if the assembly is removed for later use, coil it loosely and record its part number so the same length can be returned to service. 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.
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.
Quality Assurance and Packaging
The cable and both connectors are inspected before a functional link test. Connector protection and bend-safe packing reduce handling damage during transport and storage. Customer or site labels can be added for field inventories, with different lengths separated to simplify issue and return of spare assemblies. Neutral packaging and customer-specific packing documentation are available on request.
Arista Networks Compatibility and Factory Testing
A field-ready cable needs both correct identification and a stable operating link. Our pre-packing check therefore includes the connectors, host recognition and link behavior. For equipment with uncertain revision history, providing the host model and software release helps identify compatibility requirements before the assembly reaches the installation site. Where supported by the host, link stability and diagnostic indications are reviewed together with the established link.
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.
Can different brands be connected with the same assembly?
Only where both hosts explicitly support the complete interface and compatibility arrangement. Document each end and select the appropriate brand-specific product when required.
Does this order code cover multiple lengths?
No. CAB-D-8S-400G-3M refers here to 3m (10ft). Every other verified length has a separate part number and page in the length list.
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.
Ordering Information
Request the cable by its exact part number and length, and state the equipment model if compatibility confirmation is needed. Site orders can list quantities by rack or installation team. Any requested label should retain the part number so a removed or spare cable can still be identified accurately. This page’s fixed configuration is 3m (10ft); another length must be quoted under its corresponding part number.
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. International express, air cargo and sea freight can be selected according to destination and carton volume; customer courier accounts and nominated forwarders are also accepted.
