EPON has been widely deployed on the globe and Optical Line Terminal（OLT） is its core element.As a shared point-to-multipoint network

its security is subject to menace

so the protection of OLT is of great importance to the entire EPON.In this paper

anti-attack methods for EPON OLT are introduced

with an emphasis on the important roles of switching chips in these methods.Examples are given to explain how the EPON units are protected.