Equilibrium bandwidth and buffer allocations for elastic traffics
Consider a set of users sharing a network node under an allocation scheme that provides each user with a fixed minimum and a random extra amount of bandwidth and buffer. Allocations and prices are adjusted to adapt to resource availability and user demands. Equilibrium is achieved when all users optimize their utility and demand equals supply for nonfree resources. We analyze two models of user behavior. We show that at equilibrium expected return on purchasing variable resources can be higher than that on fixed resources. Thus users must balance the marginal increase in utility due to higher return on variable resources and the marginal decrease in utility due to their variability. For the first user model we further show that at equilibrium where such tradeoff is optimized all users hold strictly positive amounts of variable bandwidth and buffer. For the second model we show that if both variable bandwidth and buffer are scarce then at equilibrium every user either holds both variable resources or none.
© Copyright 2000 IEEE. Reprinted with permission. Manuscript received June 12, 1997; revised February 23, 1998; approved by IEEE/ACM TRANSACTIONS ON NETWORKING Editor G. Sasaki. This work was supported in part by the Australian Research Council under Grant S49813050 and Grant A49930405. Partial and preliminary results have been presented in INFORMS Applied Probability Conference, Boston, MA, June/July 1997 and in Infocom'98, San Francisco, CA, March 1998. The present much simpler proof for Theorem 2 is due to an anonymous reviewer. The author would like to thank A. Greenberg for his hospitality while a portion of this work was being performed at AT&T Laboratories.