This object specifies the name of DSCP mutation map
applied at this interface. If DSCP mutation is not performed
at the interface, then the value of this object is the
zero-length string; otherwise, the value of this object must
be the name of a row in the csqDscpMutationTable. If a row
in the csqDscpMutationTable is deleted, all instances of this
object which referenced the deleted row get changed to the
zero-length string.