; or (2) the development and maintenance of a community of practice for recipients of grants under this part and other experts in the field of school diversity. 4553. Program authorized; length of grants (a) Program authorization (1) In general From the amounts made available under section 4558 and not reserved under section 4552 for a fiscal year, the Secretary shall award grants, on a competitive basis in accordance with section 4554(b), to eligible entities described in subsection (b) to enable the eligible entities to develop or implement ambitious plans to improve diversity and reduce or eliminate socioeconomic or racial isolation in publicly funded early childhood education programs and public elementary schools and secondary schools. (2) Types of grants The Secretary may, in any fiscal year, award— (A) planning grants; (B) implementation grants; or (C) planning grants and implementation grants. (b) Eligible entity An entity that is eligible for a grant under subsection (a) is a local educational agency, a consortium of such agencies, an educational service agency, or another regional educational authority, that has significant achievement gaps and socioeconomic or racial segregation within or across the school districts served by the entity. (c) Duration of grants (1) Planning grant A planning grant awarded under this part shall be for a period of not more than 1 year. (2) Implementation grant An implementation grant awarded under this part shall be for a period of not more than 3 years, except that the Secretary may extend an implementation grant for an additional 2-year period if the eligible entity receiving the grant demonstrates to the Secretary that the eligible entity is making significant progress on the program performance measures identified in section 4556. 4554. Applications