This object will enable/disable the virtual router
function. Setting the value to `up', will transition
the state of the virtual router from `initialize' to `backup'
or `master', depending on the value of `vrrpOperPriority'.
Setting the value to `down', will transition the
router from `master' or `backup' to `initialize'. State
transitions may not be immediate; they sometimes depend on
other factors, such as the interface (IF) state.