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負載平衡之布可夫范紐曼交換機之頻寬保證
Thesis

負載平衡之布可夫范紐曼交換機之頻寬保證

虞繼堯
Masters, National Tsing Hua University
2001

Abstract

負載平衡布可夫范紐曼交換機頻寬保證截止期限最早優先時間框架有限延遲 load balancedBirkhoff-von Neumann Switchesguaranteed rate servicesearliest deadline firsttime framedelay bound
In this thesis, we propose two schemes for the load balancedBirkhoff-von Neumann switches to provide guaranteed rate services. As in [7], the first scheme is based on an EarliestDeadline First (EDF) scheduling policy. In such a scheme, weassign every packet of a guaranteed rate flow a targeteddeparture time that is the departure time from the correspondingwork conserving link with capacity equal to the guaranteed rate.By adding a jitter control mechanism in front of the buffer at the second stage and running the EDF policy at the output buffer, we show that the end-to-end delay for every packet of a guaranteed rate flow is bounded by the sum of its targeted departure time and a constant that only depends on the number of flows and the size of the switch.Our second scheme is a frame based scheme as in Keslassy andMcKeown [17]. There, time slots are grouped into fix size frames. Packets are placed in appropriate bins (buffers) according to their arrival times and their flows. We show that if the incoming traffic satisfies certain assumptions, then the end-to-end delay for every packet and the size of the central buffers are both bounded by constants that only depend on the size of the switches and the frame size. The second scheme is much simpler than the first one in many aspects:(i) the on-line complexity is $O(1)$ as there is no needfor EDF, (ii) central buffers are finite and thuscan be built into a single chip, (iii) connection patterns of the two switch fabrics are changed less frequently, (iv) there is no need for resequencing-and-output buffer after thesecond stage, and (v) variable length packets may be handled without segmentation and reassembly.

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