CAB-D-8S-400G-3MArista 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 densely populated equipment, the fixed 3m (10ft) version of Arista Networks CAB-D-8S-400G-3M offers a clearly defined 400G link without separate optical modules or patch cords. The DAC assembly uses QSFP-DD to 8x SFP56; its power, mechanical and diagnostic details are listed where supplied so port density and cable management can be assessed together.
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.
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.
High-Density Rack Integration
In a densely populated rack, connector access and airflow are part of the link design. Choose the shortest length that follows the managed path comfortably, avoid tight bundles around the connector housings and preserve room for latch operation. Where power consumption is listed, include every populated interface in the host thermal budget rather than assessing a single cable in isolation. 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.
Quality Assurance and Packaging
Each assembly receives a visual connector inspection and functional link check before it is coiled and protected. Packaging is selected to avoid compressing the cable into a tight bundle, and optional rack-based labels help maintain an orderly installation when many identical interfaces are populated together. Standard protective packing is used by default, with project documentation arranged when requested.
Ordering Information
Provide the exact part number, length, quantity and target interface density. For multi-rack projects, list each length separately and identify any preferred carton grouping. Host model and software information can be included for a compatibility review before production or dispatch. This page’s fixed configuration is 3m (10ft); another length must be quoted under its corresponding part number.
Arista Networks Compatibility and Factory Testing
The assembly is evaluated for host recognition and stable link operation, with diagnostics checked where the interface provides them. This approach verifies more than electrical or optical continuity. Exact platform and firmware information remains valuable in high-density deployments because port mode and qualification policy can differ within the same connector family. 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.
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.
How should an unused assembly be stored?
Protect both connector ends, keep the cable in a loose bend-safe coil and retain its part-number label so the length and compatibility identity remain traceable.
Shipping and Lead Time
Standard configurations normally ship within one to three working days, with production quantities confirmed at order stage. 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.
