Name: John Tsiligaridis

In the essential area of Network Management we have dealt with the subject of the scheduler reaction and adjustment in a dynamic resource environment. Different scheduling models from various areas of Computer Networks (wired and wireless) are presented. Better performance for all the cases via simulation is provided. Many methods of packets? service have been developed, associated with the borrowing of credits technique for use in the next round. A new approach for adjustment of the weights of the Deficit Round Robin (DRR) is proposed. We are dealing with the service of various large size packets and we use gradual or direct weight increases that result to the decrease of the borrowing credits. The advantage of our method lies on both the elimination of the otherwise required repeated, unexpected and uncertain changes of the next round?s credits and the guarantee of the next packet?s service with no ?empty round?. A family of algorithms that use different and systematic weight request methods, such as: the Direct Increasing Weight (DIW), the Compound Round Robin (CRR) and the Proportionally Increasing Weight (PIW) are presented below with much better performance than the DRR related to the l-packets sequence?s arrival, given that the quantum size remains constant. All these algorithms are O(1) complexity and their relative fairness along with the delay bounds are derived. Simulation experiments support the algorithms? significance and useful results are also provided. Our approach can be applied in the internet routers, achieving short time service for delay sensitive flows. The problem of the design and adjustment of the weights is examined. Some flows have excess of quantum and therefore they are serviced quickly while others don?t and remain in the queues for a long time. Many different size packets supporting new applications move around the network. Working in a dynamic environment, periodical instantly changes of the size of quanta optimizes the performance of the RR scheduler. On the other hand the dynamic allocation of the weights analogous to the packet?s size diminishes the importance of some traditional input parameters of the flows (like MTU) in the routers. We are interested in finding better allocation of the flows? quanta in order to minimize the number of the rounds, of some flows, avoiding any unnecessary increase of the total quanta amount used. This solution basically enhances the service ability of the DRR server, avoiding the ?empty rounds? and additionally offers a framework for temporary economical adjustment of the weights at the routers using various types of RR schedulers such as DRR,WRR, ERR etc. Moreover, the latency parameter of the RR scheduler is examined so that the larger size packets can be serviced without any