The Mobility Controller (MC) role is supported on a number of different platforms like, the Cisco WLC 5700 Series, CUWN and Catalyst 3850 Switches. The scale requirements on these three platforms are summarized in the table below:

Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/mobility/ configuration_guide/b_mobility_3se_3850_cg/b_mobility_32se_3850_cg_chapter_010.html

When a TLOC is configured behind NAT, the color type is assigned as public. This is because the TLOC is not accessible from the public internet, so it must use a public IP address to communicate with other TLOCs. The other color types, MPLS, private, and blue, are used for TLOCs that are accessible from the public internet.