The present invention includes a high performance communications cable or cable support-separator and/or jacket and includes one or more core support-separators having various shaped profiles. The core may be formed of conductive or insulative material and may be comprised of polymer blends that include olefin and/or fluoropolymer and/or chlorofluoropolymer based resins with or without inorganic additives such as nano-clay composites, C.sub.60 based compounds, etc. The core support-separator has both a central region as well as a plurality of shaped sections that extend outward from the central region that are either solid or partially solid, foamed or foamed with a solid skin surface. The invention includes incorporation of hollow ducts that can be used to provide for insertion of optical or metal transmission media either before, during, or after installation of the cable.