Balanced Scheduling toward Loss-Free Packet Queuing and Delay Fairness

Abstract

In current networks, packet losses can occur if routers do not provide sufficiently large buffers. This paper studies how many buffers should be provided in a router to eliminate packet losses. We assume a network router has m incoming queues, each corresponding to a single traffic stream, and must schedule at any time on-line from which queue to take the next packet to send out. To exclude packet losses with a small amount of buffers, the maximum queue length must be kept low over the entire scheduling period. We call this new on-line problem the balanced scheduling problem (BSP). By competitive analysis, we measure the power of on-line scheduling algorithms to prevent packet losses. We show that a simple greedy algorithm is (log m)-competitive which is asymptotically optimal, while Round-Robin scheduling is not better than m-competitive, as actually is any deterministic on-line algorithm for BSP. We also give a polynomial time algorithm for solving off-line BSP optimally.We also study another on-line balancing problem that tries to balance the delay among the m traffic streams.

Buffer Management Algorithms in Unbounded Buffers

“…The performance of the algorithm is measured by the sum of the lengths of buffers to transmit all the packets. This measure is different from that given in the previous work [1], which is the maximum length of the buffers.…”

“…We are concerned in minimizing the sum of lengths of buffers, which is different from the previous work [1] As the further work, the analysis of the upper bounds of the on-line algorithms is needed.…”

“…The model considered in this paper was given in [1], where the buffers have no limit of their lengths. But the authors in [1] are concerned in minimizing the maximum length of buffers.…”

“…But the authors in [1] are concerned in minimizing the maximum length of buffers. They show that the online algorithm LQF is Θሺlog ݉ሻ-competitive.…”

Management of Multi-Queue Switches in QoS Networks

“…Hahne et al [13] studied buffer management policies in this model while focusing on deriving upper and lower bounds for the natural Longest Queue Drop policy. Fleischer and Koga [12] and Bar-Noy et al [7] investigated the online problem of minimizing the length of the longest queue in a switch, which is in some sense the dual to the unit-value case we study. In their model queues are unbounded in size, hence packets are not lost.…”