Entropy-optimal Generalized Token Bucket Regulator
  We derive the maximum entropy of a flow (information utility) which conforms to traffic constraints imposed by a generalized token bucket regulator, by taking into account the covert information present in the randomness of packet lengths. Under equality constraints of aggregate tokens and aggregate bucket depth, a generalized token bucket regulator can achieve higher information utility than a standard token bucket regulator. The optimal generalized token bucket regulator has a near-uniform bucket depth sequence and a decreasing token increment sequence. 
Ashutosh Deepak Gore and Abhay Karandikar