The value that all bridges use for MaxAge when this bridge is acting as the root. Note
that 802.1D-1990 specifies that the range for this parameter is related to the value of
zyxelMrstpBridgeInfoHelloTime. The granularity of this timer is specified by 802.1D-1990
to be 1 second. An agent may return a badValue error if a set is attempted to a value
which is not a whole number of seconds.