One of the loudest argument against ZigBee has been
the lack of industrial-grade robustness. First of all, there is
no frequency diversity since the entire network shares the
same static channel, making it highly susceptible to both
unintended and intended jamming. This also means that
the severe frequency selective fading due to the metal-rich
propagation environments in plants potentially can stop all
ZigBee communication. Moreover, the static channel will
also increase interference for other systems like wirelessLAN,
and increase delay as the network size grows and
collisions forces re transmissions.