Huawei Huawei CTTC Telefonica Ericsson 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 channel spacings, a set of nominal central frequencies, 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 and in RFCs 7698 and 7699, this document describes the Open Shortest Path First - Traffic Engineering (OSPF-TE) extensions in support of GMPLS control of networks that include devices that use the new flexible optical grid.