The value of tmnxMcacBdlChlClass specifies the channel's class.
The channel with value of high has higher priority than
channel with value of low.
The combination of tmnxMcacBdlChlClass and tmnxMcacBdlChlType
is used to define the priority of channels. If there exists
channels with same combination then round robin is used to
determine the channels that need to be dropped if any of the
CAC constraints are met.