${\lambda }_{xn}^{sd}$

Portion of traffic demand $\left(s,d\right)$ traversing physical link $\left(x,n\right)$ .

${\gamma }^i$

Binary variable equals 1 to indicate OLT switch is active, otherwise equal 0.

${\Lambda }^{sd}$

Binary variable equals 1 if demand $L^{sd}$ is not served, otherwise equals 0.

${\zeta }^{ij}$

Binary variable equals 1 to indicate if OLT port is active, otherwise equals 0.

${\beta }^i$

Binary variable equals 1 to indicate if ONT is active, otherwise equals 0.

${\psi }^i$

Number of activated ports in OLT switch i.