  We establish tight bounds for beacon-based coverage problems, and improve the
bounds for beacon-based routing problems in simple rectilinear polygons.
Specifically, we show that $\lfloor \frac{n}{6} \rfloor$ beacons are always
sufficient and sometimes necessary to cover a simple rectilinear polygon $P$
with $n$ vertices. We also prove tight bounds for the case where $P$ is
monotone, and we present an optimal linear-time algorithm that computes the
beacon-based kernel of $P$. For the routing problem, we show that $\lfloor
\frac{3n-4}{8} \rfloor - 1$ beacons are always sufficient, and $\lceil
\frac{n}{4}\rceil-1$ beacons are sometimes necessary to route between all pairs
of points in $P$.
