Make connections in data Centre high speed direct attach cables
Twinax cable assembly or high-speed direct-attach cables are common in data centres. An alternate cabling system for high-speed (10G-400G) connectivity to fibre optic transceivers, with more density and cheaper cost. Let's take a closer look at DAC cables, the technology behind high-speed data centre connectivity, and what they can do for you.
Do You Know What is DAC Cable?
Direct attach cables (or DAC cables) are a sort of Twinax cable with pre-installed connectors on both ends, designed for use with "transceivers," and available in various lengths for transmissions of up to 15 metres.
These cables are made up of 24 to 30AWG shielded copper coaxial or fibre optic HDMM30CM cables with pluggable transceivers at either end.
Throughputs of 10Gbps, 40Gbps, and beyond can be attained over 100 metres of active optical cable, or 15 metres when using triaxial.
Three types of DAC cables are currently in wide use: Coaxial DAC Cables Interconnects with Active DAC Technology and Optically-Active Wires.
DAC Cables: Passive vs. Active
For example, there are two types of high-speed direct attach cable: direct attach copper cable (DACC) and direct active optical cable (DAOC). For specifics, peruse AOC cables.
Active or passive DACC cables are available. The passive DAC cable has a maximum connection distance of 7 metres and uses only 0.15 watts of electricity. Active DAC cables, on the other hand, have electrical components in the connectors that can enhance signal levels, allowing for higher transmission distances (up to 5 metres) and better quality over copper medium. Because of this, the cost of active copper cables is slightly more than that of passive copper cables used for direct attachment, and their power requirements are slightly higher.
Similar to a direct attach copper cable, a direct active optical cable attaches the fibre connection inside the transceiver ends to create a full fibre cable assembly, but with a reach of 15 metres, a 2x improvement over the limit of a passive DAC.
The typical power consumption of an ACC does rise to about 0.5-1.0 W due to the extra circuitry it contains.
Optical Transceiver Module vs. Direct Attach Cable
Connecting switches in a stack or between switches and routers or servers require DAC, AOC J9283D 10G SFP+ to SFP+ 3m Direct Attach InfiniBand cable, and optical transceiver modules. DAC and AOC cables are fixed cable assemblies with different form factor connections on both ends; optical transceiver modules require fibre cables to be connected to the transceiver module. For more info, check out this DAC vs. AOC cable comparison.
The table clearly shows that high-speed direct-attach cables save money and resources. However, the range is typically shorter than that of a transceiver connected by wires. Therefore, a better-performing DAC cable provides an easier and cheaper alternative for every short-range connection measuring between 5m and 100m. However, optical transceivers are recommended when the distance exceeds 100 metres.
Interconnect for High-Speed Data Centers
Connecting new and old devices, high-speed direct-attach J9734A InfiniBand cable exists in a wide variety of designs that help to minimise expenses at every interface. Top-of-rack switches with 32 to 56 ports and support for up to 128 links require DAC cables (4x25G times 32 ports). Commonly, DAC cables with a greater data rate are compatible with DAC twinax cables with a lower data rate. There are 10G SFP+ DAC cables that are backwards compatible with 1 Gb/s.
Various DAC cables come in the following shapes and sizes:
- 10G SFP+ cables
- 25G SFP28 cables
- 40G QSFP+ cables
- 56G QSFP+ cables
- 100G QSFP28 DAC
- 200G QSFP56 DAC
- 400G QSFP-DD DAC
- QSFP-4SFP Breakout cables
- QSFP28-4SFP28 Breakout cables
- 200G DAC Breakout Cables
- 400G DAC Breakout Cables