The spectrum of spin wave excitations on a nanometric two-dimensional periodical array of circular holes in a magnetic film was measured using the Brillouin light scattering technique. Two modes with positive group velocity in the frequency range between 4 and 7 GHz were observed. Our calculations show that these correspond to the two lowest modes propagating along the edges of an effective stripe waveguide, perpendicular to the applied field, whose width is equal to the interhole distance. Moreover, a number of higher-frequency modes has been measured and identified as volume excitations of the same effective stripe. (c) 2008 American Institute of Physics.