Analyze the relationship between 'Equinix' and 'data center' within the context of the input sentence.
Options: employer, distributed by, member of, product/material produced

Historically, Digital Realty has been a "wholesale" data center operator with a real estate focus, while Equinix has more technology DNA, as well as $7.5 billion of capital invested thus far to build out its interconnection focused "Platform Equinix."
product/material produced