As data center networks transition toward 800Gb/s connectivity, high-speed interconnection is becoming increasingly important for switches, servers, AI computing systems, and high-performance computing platforms. However, not every 800G deployment uses the same port configuration. Some systems require a direct 800G-to-800G connection, while others need one 800G interface to communicate with two separate 400G ports.
The DAC 800Gb/s cable provides a practical copper interconnect option for these short-distance, high-bandwidth applications. Depending on the network architecture, the cable can be configured as an 800G-to-800G connection or an 800G-to-2×400G breakout connection. Available 800G interfaces include OSFP and QSFP-DD, while compatible 400G configurations can use OSFP112-RHS or QSFP112.
For data center operators, network engineers, system integrators, and HPC infrastructure designers, understanding the differences between these configurations is essential when planning an efficient 800G network.
What Is an 800G DAC Cable?
DAC stands for Direct Attach Copper. Unlike an optical link that uses separate transceiver modules and fiber cabling, a DAC integrates the electrical connection and connector assemblies into a single cable solution.
An 800G DAC is designed for high-bandwidth connections between compatible network devices over relatively short distances. It is particularly useful when switches, servers, NICs, or computing equipment are installed within the same rack or in nearby racks.
There are two primary configurations to consider. An 800G-to-800G DAC connects two compatible 800G ports directly. An 800G-to-2×400G breakout DAC connects one 800G interface with two independent 400G interfaces.
The correct configuration depends on the port architecture supported by the equipment rather than simply the maximum data rate printed on the product label.
When Should You Choose 800G to 2×400G Breakout?
An 800G breakout cable becomes useful when a high-speed switch or network device provides an 800G port while the connected equipment offers two compatible 400G interfaces.
For example, an 800G switch can potentially connect to two 400G network interfaces using a suitable breakout architecture. This can be valuable during network upgrades, when part of an infrastructure has already moved to 800G while other equipment remains at 400G.
Typical applications can include:
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Connecting 800G switches with two 400G ports
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Linking high-speed switches with 400G servers or NICs
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Supporting gradual migration from 400G to 800G
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Connecting high-density data center equipment
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Building mixed-speed Ethernet networks
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Supporting high-performance computing interconnects
However, a breakout cable does not automatically make every 800G port compatible with two 400G connections. The switch, NIC, adapter, and software configuration must support the corresponding lane architecture and breakout mode.
Checking the equipment manufacturer's compatibility documentation before deployment is therefore essential.
800G-to-800G DAC or 800G Breakout DAC?
The simplest way to select between these cable types is to examine the interfaces at both ends of the link.
An 800G-to-800G DAC has an 800G connector at each end and is appropriate when both devices provide compatible 800G ports.
An 800G-to-2×400G breakout cable has one 800G connector on one side and two 400G connectors on the other. It is intended for a network architecture where one 800G interface needs to communicate with two 400G interfaces.
| Network Connection | Recommended Configuration |
|---|---|
| 800G port to 800G port | 800G-to-800G DAC |
| 800G port to two 400G ports | 800G-to-2×400G breakout DAC |
| Compatible 800G OSFP ports | OSFP 800G DAC |
| Compatible 800G QSFP-DD ports | QSFP-DD 800G DAC |
| 800G interface to two compatible 400G interfaces | 800G breakout DAC |
The physical form factor and supported operating mode should always be considered together. Selecting a cable solely because it supports 800Gb/s is not enough.
Available 800G Form Factors
Modern networking equipment can use different connector designs, so connector compatibility is a major consideration.
The DAC 800Gb/s cable portfolio from Infinol supports OSFP and QSFP-DD configurations on the 800G side. For breakout applications, the 400G side can be configured according to the required equipment interface, including OSFP112-RHS and QSFP112 options.
For direct OSFP connections, the OSFP-800G-CU series provides different cable lengths. For example, the OSFP-800G-CU1M is a 1-meter OSFP-to-OSFP Twinax copper cable, while the OSFP-800G-CU2M provides a 2-meter configuration.
For equipment using QSFP-DD, the QDD-800G-CU1M and QDD-800G-CU2M provide corresponding QSFP-DD-to-QSFP-DD connections.
For breakout configurations, the exact connector combination should be matched with the switch and endpoint models before ordering.
Why Twinax Copper Is Suitable for Short 800G Links
Optical connectivity is useful for longer distances, but many high-density data center connections only need to span a few meters. In these cases, Twinax copper DAC can provide a practical alternative.
The Infinol 800G DAC supports cable lengths from 1 to 3 meters, making it suitable for connections within a rack or between equipment positioned in adjacent racks.
A direct attach copper cable can simplify short-distance installation because the cable assembly does not require separate optical transceivers and fiber patch cords. This can reduce the number of individual components involved in a short link.
For 1-meter or 2-meter rack connections, a properly matched DAC can provide a compact and straightforward high-speed interconnect.
Cable routing should still be planned carefully. The selected length should provide enough flexibility for rack installation without creating excessive cable slack or restricting airflow around high-density equipment.
Low Power Consumption for High-Density Networks
Power efficiency becomes increasingly relevant as network port speeds and deployment densities increase.
The DAC 800Gb/s cable is designed for low power dissipation and uses a single 3.3V power supply. Although the consumption of an individual cable is only one part of the total network power budget, the cumulative effect can become significant when large numbers of 800G links are deployed.
Network engineers should evaluate the complete connection, including switch hardware, network adapters, transceivers where applicable, cooling infrastructure, and rack-level power requirements.
Where a short copper connection is technically appropriate, the power characteristics of DAC technology can make it attractive for dense 800G interconnect environments.
800G Ethernet and InfiniBand NDR Applications
High-speed DAC applications extend beyond conventional Ethernet networks. The Infinol 800G cable supports 800G Ethernet and InfiniBand NDR environments, making it relevant to high-performance computing and data-intensive infrastructure.
InfiniBand NDR is used in environments where computing nodes require high bandwidth and efficient interconnection. AI clusters, HPC platforms, and other intensive computing systems can contain large numbers of high-speed links, making appropriate cable selection an important part of infrastructure design.
For these deployments, the cable must match the connector, lane configuration, protocol requirements, and operating mode of the network equipment.
An 800G breakout configuration can also be considered where an 800G network fabric needs to communicate with compatible 400G endpoints.
What Specifications Should Be Checked Before Ordering?
Before purchasing an 800G DAC, network designers should review several specifications instead of focusing only on bandwidth.
1. 800G connector type
Determine whether the switch or device requires OSFP or QSFP-DD.
2. 400G connector type
For breakout applications, confirm whether the equipment requires OSFP112-RHS, QSFP112, or another supported interface.
3. Cable length
Infinol's 800G Twinax solutions support 1–3 meter configurations. Choose a length suitable for the actual rack layout and cable management requirements.
4. Breakout support
Confirm that the 800G switch port supports operation as two 400G links when using a breakout configuration.
5. Protocol compatibility
Check whether the equipment and cable are intended for the required Ethernet or InfiniBand application.
6. Environmental requirements
The listed commercial operating temperature range is -5°C to 70°C.
7. Standards and compliance
The product family is designed around relevant OSFP, QSFP-DD, and QSFP112 MSA requirements, CMIS and IEEE 802.3 specifications, and RoHS requirements.
Reviewing these factors before ordering can prevent connector mismatches and network integration issues.
Infinol 800G DAC Product Options
Infinol provides both OSFP and QSFP-DD versions for its 800G Twinax copper cable portfolio.
The OSFP-800G-CU1M and OSFP-800G-CU2M provide 1-meter and 2-meter OSFP-to-OSFP connections. These configurations support 800GBASE-CR8 and are specified for 2×400GBASE-CR4 lane configurations.
For QSFP-DD equipment, the QDD-800G-CU1M and QDD-800G-CU2M provide corresponding 1-meter and 2-meter direct connections.
The platform supports data rates up to 800Gb/s, with specifications extending to operation up to 850Gb/s and up to 106.25Gb/s per channel. The cables are hot-pluggable and incorporate digital diagnostic functionality.
The exact product configuration should be selected according to the switch, server, NIC, or accelerator equipment being connected.
Why Supplier Capability Matters for 800G Interconnects
As data rates increase, cable assemblies become an important part of overall network reliability. Consistent manufacturing, connector quality, electrical performance, testing, and product compatibility can all affect deployment results.
Infinol Technology (Shenzhen) Co., Ltd focuses on optical communication products and high-speed interconnection solutions. Its portfolio covers optical transceivers and high-speed connectivity products for 100G, 200G, 400G, and 800G applications.
The company also provides DAC and AOC solutions for data communication, storage, and high-performance computing, together with high-density MPO and MTP trunk cabling for data center infrastructure.
For customers with application-specific requirements, the company supports OEM and ODM services covering active and passive optoelectronic communication products. Its product applications include Ethernet, Fibre Channel, InfiniBand, SONET/SDH, OTN, CPRI, and PON technologies.
Building a Practical 800G Interconnect Strategy
Moving to 800G does not mean every network connection has to be an 800G-to-800G link. In many data center architectures, different generations of equipment need to operate together during a technology transition.
An 800G-to-2×400G breakout DAC can provide a practical connection method when one 800G port needs to communicate with two compatible 400G interfaces. Meanwhile, a straight 800G DAC remains the appropriate choice when both endpoints have matching 800G ports.
The key considerations include connector form factor, breakout capability, cable length, supported protocol, lane configuration, operating environment, and equipment compatibility.
For short-distance connections where copper technology is appropriate, the DAC 800Gb/s cable offers a direct interconnect approach with OSFP and QSFP-DD options, 1–3 meter reach, low power characteristics, and support for 800G Ethernet and InfiniBand NDR environments.
By matching the cable architecture to the actual switch and endpoint interfaces, data center designers can build high-speed networks that accommodate both current infrastructure and phased upgrades. For projects requiring compatible high-bandwidth copper interconnects, the DAC 800Gb/s cable from Infinol Technology (Shenzhen) Co., Ltd provides a practical option for modern 800G data center and high-performance computing applications.
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Infinol Technology (shenzhen) Co., Ltd
