Data Center

How To Migrate from Base-12 to Base-8 Connectivity

Matt Hurst

Making use of fiber links in increments of 12, with 12-fiber connectors such as MPO, Base-12 connectivity was born in the mid-1990s. This innovation helped manage the growth of data center fiber infrastructure as the number of fiber port deployments grew from dozens to thousands (or even tens of thousands).

More than two decades old now, Base-12 addressed data center needs for modular, high-density structured cabling systems and improved port density. But a new technology is emerging that could gain widespread acceptance in the next few years: Base-8.

The technology behind data center switches, servers and transceivers is changing quickly to accommodate the ever-increasing adoption of cloud computing, along with a growing demand for high-bandwidth applications, such as streaming video.

As you may have guessed, Base-8 connectivity makes use of fiber links in increments of eight versus 12. The 12-fiber trunk cables are replaced with trunk cables in increments of eight: eight-fiber trunk cables, 16-fiber trunk cables, 24-fiber trunk cables, etc. Multimode and singlemode fiber-optic circuits constructed in groups of eight are an efficient way for data centers to achieve high-speed connections needed to keep up with demand.

Transceivers are guiding our industry from 10G to 40G, 100G and even 400G Ethernet protocols, causing data centers to migrate in order to handle faster transmission speeds – and connectivity is adapting to keep up. For example, QSFP transceivers (quad small form-factor pluggable) are commonly deployed in today’s data centers (including QSFP+ and QSFP28) – these transceivers are optimized for Base-8 protocols because transceiver only utilizes eight fibers.

Where Base-8 Shines

Because of the adoption of 40G or 100G in data centers, Base-8 connectivity will be a strong contender in some of the following applications:

  • SR4 protocols (40G or 100G over parallel MMF)
  • PSM4 protocols (100G over parallel SMF)
  • SAN switch Base-8/Base-16 port arrangements

But Base-8 connectivity isn’t ideal for every situation, including duplex protocols like 25G and 100G (duplex SMF). And it also doesn’t offer any density benefits as compared to Base-12.

Is Gradual Base-8 Migration Possible?

If you plan to migrate from Base-12 to Base-8 over time, it is possible to deploy both Base-8 and Base-12 connectivity within same data center – just as long as the links are maintained separately. Base-8 and Base-12 fiber links cannot be mixed and matched.

Base-12 and Base-8 protocols both make use of MPO connectors, but the use of Base-12 fiber in a Base-8 system results in four fibers being “dark” or unutilized in the channel (12 - 8 = 4).

If your data center is migrating from 10G to 40G, Base-8 connectivity should be a strong consideration over Base-12.

Belden solutions were designed with your data center migration process in mind. Our full Base-8 Solution Set includes cassettes, trunks, patch cords, hydra assemblies, optimizer cassettes and more. Belden Base-8 cassettes share the FX UHD system form factor, which means there’s no need replace patch panel infrastructure when you migrate – you can keep what you have (which is rare!). Base-12 cassettes can be replaced with Base-8 cassettes in a simple swap – the Belden FX UHD ecosystem is completely modular.


By combining three eight-fiber trunks into two new 12-fiber connections, FX UHD Optimizer cassettes let you utilize existing 12-fiber trunks and eliminate dark fibers in a Base-8 conversion.