  We extend the Zamolodchikov-Faddeev algebra for the superstring sigma model
on $AdS_{5}\times S^{5}$, which was formulated by Arutyunov, Frolov and
Zamaklar, to the case of open strings attached to maximal giant gravitons,
which was recently considered by Hofman and Maldacena. We obtain boundary
$S$-matrices which satisfy the standard boundary Yang-Baxter equation.
