Release of unnecessary resource reservation in mobility cases

Resource reservation in mobile environments is an important task in the future when the userpsilas point of attachment to the network changes frequently due to mobility. One crucial issue of this task is to release unnecessary reservation along old path after departure of mobile node(s). Although this can be done automatically by a soft state mechanism, default soft statepsilas lifetime which is conceived for wired network case is not suitable to mobility. In this paper, we introduce an additional value to soft statepsilas lifetime to optimize resource release along old path: besides the default value which is used when no handover occurs, the additional value is assigned when handover takes place. Through the comparison with three other mechanisms, we observe that our proposed mechanism outperforms the others in term of average cost and blocking probability.