SMF vs MMF as the default choice in data centres
Sun 18 Mar 2018 | Michael Akinla
A key challenge for the date centre owner/operator in 2018, is identifying what the target client/user is and their data requirements. For most there is a trade-off between performance and cost and therefore the type of fibre to install; single-mode or multimode. Further to that, if multimode, which Category: OM3, OM4, or OM5(+) enhanced cable systems. Another interesting spanner in the works, is the EU Legislation MiFID II, which, in many financial colocation data centres, will require increased fibre cable runs to ensure regulatory ‘latency equalisation’ compliance. So, it isn’t a simple choice, but a total understanding of your data centre’s use and customers’ needs today and future upgrade requirements that define the infrastructure.
Single-Mode Fibre (SMF) will support all future data rates and channel reaches, but the performance comes at a cost premium of 3 to 5 times that of multimode channels. For SWDM, wide-band fibre systems such as OM5 and OM5+ will be required to guarantee performance over the specified channel reaches with a high degree of confidence. For data rates, up to 400Gb/s, there is minimal, if any risk in using existing structured cabling comprising OM3 and OM4 fibre types. However, channel efficiency, and therefore performance, can be compromised by marginally compliant fibres.
As data rates increase and technology evolves, lower data rates will become obsolete. Consequently, the structured cabling should be capable of supporting future specified higher data rate network infrastructure. This suggests the deployment of parallel OM3 or OM4 fibres for short channel reaches less than 75 meters and OM5(+) for reaches up to 150m. Single-mode will likely continue to be more expensive for at least 5- to 10-years.
For most data centre operators, the discussion is framed around increased bandwidth, reduced or equalised latency, and energy concerns including lower power usage and reduced heat generated by the system. Viewed against the alternative cabling systems, fibre offers benefits as a solution, whether a single fibre type or as a mixed fibre infrastructure to advance the high-performance requirements of data centres now and in the longer-term.