Looking Ahead: An Introduction to 400g Transceivers
As the market for 100G optical transceivers continues to mature, we’ve started to look ahead to the next frontier: 400G.
According to a report from this year’s OFC conference, studies have shown a 25% annual increase in data center interconnect applications, driven largely by increases in consumer demand for cloud computing, video streaming, and other bandwidth-intensive services.
In the first installment of a new series, we’ll introduce the open standards-based form factors currently in development and share our prediction on which one will become industry standard.
CFP8 with MPO connector for 400GBASE-SR16 applications (via www.cfp-msa.org)
First proposed as a form factor in 2015, the CFP8 is the newest addition to the CFP family of form factors. It employs a 16x25G electrical interface that makes use of currently-available 25G components. This design requires a larger enclosure (roughly the size of a CFP2), which results in lower port density per rack unit. We believe this to be a fatal flaw, particularly in the data center applications that will employ these transceivers. Similar concerns over port density saw the CFP2 overtaken by the QSFP28 in the 100G marketplace.
The OSFP (Octal SFP) was first proposed in 2017 and seems to be better suited to the data center environment than the CFP8. It uses an eight-lane (8x50G) electrical interface, enabling a smaller form factor that can fit up to 36 ports in 1 standard rack unit, for over 14TB/s of bandwidth. However, it would still require an adapter for backward compatibility with legacy QSFP28 transceivers.
Much like the OSFP, the QSFP-DD (double-density QSFP) will use an eight-lane electrical interface. Since this form factor is slightly smaller than the OSFP, it will be able to fit more ports per 1RU faceplate. Additionally, it will consume less power, so the associated operational expenses will be lower. We expect these features – plus the potential for backward compatibility— to be the key differentiators over the OSFP.
Therefore, given the information available at this time, we believe the QSFP-DD will become the industry standard for 400G data center applications.
Are you thinking about exploring your 400G options? Contact us today, and stay tuned to our blog for more in-depth coverage and news on the emerging 400G market.