What Is Breakout Cable?_
In data center cabling, breakout cables are used to transition from a high-speed, high-density interface (like a 400G QSFP-DD or OSFP port) to multiple lower-speed interfaces (e.g., 4x100G or 8x50G). They typically consist of a single MPO-12 or MPO-24 connector on one end fanning out to multiple duplex LC or single MPO connectors on the other. This allows efficient use of switch port capacity and simplifies cable management in structured cabling systems.
Technical Details
Breakout cables are commonly deployed with parallel optics transceivers, where the optical signal is split into separate fiber strands for each lane. The fan-out side often uses MPO-12 or MPO-24 connectors for 8- or 12-fiber groupings, while the trunk side may use a higher-density MPO-24 or MPO-48 connector. Cable lengths are typically limited to short reaches (e.g., within a rack or adjacent rows) to avoid excessive signal loss, and the exact loss budget must comply with the relevant transceiver standard. Polarity management (e.g., Type A, B, or C) is critical to ensure proper transmit-receive pairing across the breakout.
How Leviathan Systems Works with Breakout Cable
In our field work, breakout cables are frequently used when connecting GPU nodes to leaf switches in the scale-out network, especially when transitioning from 400G switch ports to 100G NICs. We also see them in liquid-cooled racks where dense fiber trunks from the top-of-rack switch must fan out to individual GPU server ports.
Related service
Structured Cabling Services →