The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) has extended its Recommendations G.694.1 and G.872 to include a new Dense Wavelength Division Multiplexing (DWDM) grid by defining a set of nominal central frequencies, channel spacings, and the concept of the "frequency slot". Corresponding techniques for data-plane connections are known as flexi-grid. Based on the characteristics of flexi-grid defined in G.694.1, RFC 7698 and 7699, this document describes the OSPF-TE extensions in support of GMPLS control of networks that include devices that use the new flexible optical grid.