The CMS detector will undergo a major upgrade for Phase-2 of the LHC program, starting around 2026. The upgraded Level-1 hardware trigger will select events at a rate of 750 kHz. At an expected event size of 7.4 MB this corresponds to a data rate of up to 50 Tbit/s.
Optical links will carry the signals from on-detector front-end electronics to back-end electronics in ATCA crates in the service cavern. A DAQ and Timing Hub board aggregates data streams from back-end boards over point-to-point links, provides buffering and transmits the data to the commercial data-to-surface network for processing and storage. This hub board is also responsible for the distribution of timing, control and trigger signals to the back-ends.
This paper presents the current development towards the DAQ and Timing Hub and the design of the first prototype, to be used as for validation and integration with the first back-end prototypes in 2019-2020.