1. Industry Background: Why Choose 40G Breakout DAC Cable?

Nowadays, under the rapid development of big data, artificial intelligence, Internet of Things and other network technologies, 10G network can no longer cope with the future traffic demand. In order to meet the upgrade of 10G network, and based on the low cost and high efficiency factors, 40G QSFP+ to 10G SFP+ DAC branch high-speed cable has become the preferred interconnection scheme for the short-distance 10G upgrade of 40G network.In this article, ETU-LINK Technology (ETU-LINK) will introduce the 40G QSFP+ to 10G SFP+ DAC branch high-speed cable.

Traditional upgrade solutions using separate 40G optical modules plus four groups of 10G fiber jumpers will increase port occupancy, wiring clutter and extra power consumption. Breakout twinax copper cable integrates one QSFP+ main end and four independent SFP+ sub-ends, splitting a single 40G port into four independent 10G channels, maximizing existing 10G server/NIC resources without replacing all end devices.

2. Basic Definition & Working Principle of QSFP+ to SFP+ Breakout DAC

We all know that DAC direct attach cables are mainly used for the connection between servers in data center racks and the connection between servers and switches (the height of a standard cabinet does not exceed 3 meters) or the interconnection of equipment in adjacent racks. More servers accessing high-speed switches can help reduce the number of low-speed switches and save space.

The 40G QSFP+ to 10G SFP+ DAC branch high-speed cable complies with the latest SFP+/QSFP MSA (multi-source agreement), which can build a bridge between 10G and 40G switches/host adapters. The maximum transmission rate of the SFP+ module of the 40G branch high-speed cable can be Up to 10.3125Gbps (aggregate 40Gbps). In addition, high-wire cables can reduce power budgets compared to optical fibers.

3. Main Application Scenarios of Breakout DAC Cable

40G QSFP+ to 10G SFP+ DAC branch high-speed cable can not only realize the interconnection of 10G switch and 40G switch and the interconnection of server and switch (the interconnection of QSFP+ port of switch and SFP+ port of server network card NIC/HBA), but also the connection of switch and The interconnection of converters (transmission relays) achieves the purpose of interconnection with remote network equipment.

Typical deployment scenarios: small and medium data center ToR cabinet interconnection, virtualization cluster server access, storage SAN short-distance convergence, campus network core aggregation layer upgrade, cloud computing edge node wiring

4. Two Main Types of 40G High-Speed DAC Cables

In addition to 40G QSFP+ to 10G SFP+ branch cables, 40G DAC high-speed cables also have 40G QSFP+ to QSFP+ DAC, which can be used for short-distance stacking and assembly between devices with QSFP ports. 

Product classification comparison:
Breakout DAC (QSFP+ to 4SFP+): Split one 40G port into four 10G channels, suitable for mixed 10G/40G network migration; available lengths: 0.5m/1m/2m/3m
Straight-through QSFP+ DAC: Both ends QSFP+ 40G ports, for 40G switch stacking and spine-leaf core interconnection
Besides passive DAC, ETU-LINK also supplies QSFP+ breakout AOC active optical cables for cross-cabinet transmission over 5–10m.

5. Core Advantages of Using Breakout DAC for Network Upgrade

The new generation of 40G/100G data center takes a long time to prepare, so upgrading from the current 10G network is the most cost-effective way.

1). Cost saving: Replace four groups of 10G SFP+ optical modules and fiber jumpers with one breakout cable, cutting hardware procurement and wiring labor costs;
2). Space optimization: Reduce cable quantity inside cabinets, simplify cable management and improve heat dissipation of equipment;
3). Low latency & low loss: Copper twinax has no photoelectric conversion loss, lower transmission delay than optical link;
4). Plug-and-play hot swap: Fully MSA compliant, support switch breakout mode configuration without extra firmware modification;
5). Wide compatibility: Pass real machine testing on mainstream brand switches and servers, stable long-term operation.

Last updated: July 10, 2026