This object specifies the Traffic Shaper Maximum
Cell Buffer Threshold for the VBR Traffic Class.
The value of this object is expressed as a percent
of the value of rtsIfMaxThreshold object. A set
request for this object will succeed only if the
value of the ifAdminStatus object for this
interface is 'down'. The Traffic Shaping hardware
may not have the support to represent all the
values and hence the value installed in hardware
could be different. And the value installed in
hardware will be available through the object
rtsIfVbrClassMaxThrshInstalled. This object is
not instantiated for interfaces to which
it cannot be applied.