A low dispersion photonic crystal waveguide with triangular lattice elliptical airholes is proposed for compact, high-performance optical buffering applications. In the proposed structure, we obtain a negligible-dispersion bandwidth with constant group velocity ranging from $c/41$ to $c/256$ , by optimizing the major and minor axes of bulk elliptical holes and adjusting the position and the hole size of the first row adjacent to the defect. In addition, the limitations of buffer performance in a dispersion engineering waveguide are well studied. The maximum buffer capacity and the maximum data rate can reach as high as $262\text{\hspace{0.17em} bits}$ and 515 Gbits/s, respectively. The corresponding delay time is about $255.4\mathrm{ps}$ .