Is there a “sweet spot” for data centers transitioning from 10GBASE-T to higher speeds?  Based on recent market surveys and technical feasibility analysis, the answer is definitely yes.  Trends for cloud servers and the latest forecast on server port speeds, both reported by Dell’Oro, lead to the conclusion that 25GBASE-T is a critical and heretofore lacking point on the migration roadmap to 40GBASE-T.  In addition, multiple feasibility presentations have clearly demonstrated that 25GBASE-T can allow users to leverage capital investment and research and development in 10GBASE-T and 40GBASE-T technology to optimize deployment costs as server and switch data speeds incrementally increase.

The IEEE 802.3 Ethernet Working Group formally approved merging the initiative to develop 25GBASE-T application requirements with the IEEE P802.3bq project to develop 40GBASE-T in September of 2015.  25GBASE-T will support the benefits of backwards-compatible BASE‑T technology and both 25GBASE-T and 40GBASE-T are planned for operation over TIA category 8 and ISO/IEC class I and class II cabling.  The deployment opportunity for 25GBASE-T is aligned with 40GBASE-T and defined as the same 2-connector, 30 meter reach topology supporting data center edge connections (i.e., switch to server connections in row-based structured cabling or top of rack configurations).  Interestingly, it is anticipated that frequency scaling will be employed to characterize the channels supporting 25GBASE-T (i.e. channels will characterized to 1,250 MHz) and 40GBASE-T (i.e. channels will characterized to 2,000 MHz).

The IEEE 802.3 802.3bq amendment specifying physical layer and management parameters for 25GBASE-T and 40GBASE-T operation is on the fast track; with publication anticipated mid-2016.  This is definitely one application to watch!