This document captures the semantics of the "Footprint and Capabilities Advertisement" part of the CDNI Request Routing interface, i.e., the desired meaning of "Footprint" and "Capabilities" in the CDNI context, and what the "Footprint and Capabilities Advertisement Interface (FCI)" offers within CDNI. The document also provides guidelines for the CDNI FCI protocol. It further defines a Base Advertisement Object, the necessary registries for capabilities and footprints, and guidelines on how these registries can be extended in the future.