Optimization of Token Holding Times in Split Light Trail Networks
Optimization of Token Holding Times in Split Light Trail Networks
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DOI：
10.1109/glocom.2011.6133810
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发表时间：
2011-12
期刊：
影响因子：
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通讯作者：
Wenjie Chen;Y. Fukushima;T. Yokohira
中科院分区：
文献类型：
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作者：
Wenjie Chen;Y. Fukushima;T. Yokohira
作为一种新的光WDM网络结构，可以建立与目前可用的设备，并可以实现带宽分配的粒度比波长，光尾迹结构吸引了人们的注意。因为光路是共享介质，所以我们需要介质访问控制（MAC）协议来避免冲突。虽然使用令牌传递的MAC协议可以避免冲突，但位于令牌持有节点上游的链路的带宽保持空闲。在本文中，我们首先提出了一个动态的光路分裂方法，以增加通过使用这些空闲带宽的光路的吞吐量。我们的方法在令牌持有节点处将踪迹分成上游踪迹和下游踪迹，并且允许两条踪迹上的独立数据传输。因此，我们预计，分裂线索架构实现更高的最大吞吐量比原来的非分裂线索架构。分割路径架构的吞吐量改善程度取决于我们如何适当地设置每个传输节点的上游和下游令牌持有时间。因此，我们制定了一个问题，以决定令牌持有时间作为一个非线性规划问题，推导出的最大吞吐量的分裂线索架构，通过使用NUOPT求解器解决这个问题，并调查的程度相比，原来的架构的改进。根据数值示例，分裂路径架构实现了1）对于其不喜欢的业务模式几乎与原始架构相同的最大吞吐量，其中每个传输节点仅向路径的终止节点发送数据，2）对于均匀业务模式大约1.6倍的最大吞吐量，其中每个节点对请求相同的业务量，以及3）对于每个传输节点仅向其相邻的下游节点发送数据的其最喜欢的业务模式，大约1.9倍的高最大吞吐量。
As a new optical WDM network architecture that can be built with currently available devices and can achieve bandwidth allocation with granularity finer than a wavelength, a light trail architecture attracts attention. Because a light trail is a shared medium, we need a medium access control (MAC) protocol to avoid collisions. Although MAC protocols using token passing can avoid collisions, bandwidths of links that locate upstream of the token holding node are kept idle. In this paper, we first propose a dynamic light trail splitting method in order to increase throughput of a light trail by using those idle bandwidths. Our method splits a trail into the upstream trail and the downstream trail at the token holding node and independent data transmissions on the two trails are permitted. As a result, we expect that the split trail architecture achieves higher maximum throughput than the original non-split trail architecture. The degree of throughput improvement by the split trail architecture depends on how appropriately we set upstream and downstream token holding times of every transmission node. Thus, we formulate a problem to decide the token holding times as a nonlinear programming problem, derive the maximum throughput of the split trail architecture by solving the problem using NUOPT solver, and investigate the degree of improvement compared to the original architecture. According to numerical examples, the split trail architecture achieves 1) almost the same maximum throughput as the original one for its unfavorite traffic pattern where every transmission node sends data to the terminating node of the trail only, 2) about 1.6 times as high maximum throughput for a uniform traffic pattern where every node-pair requests the same traffic volume, and 3) about 1.9 time as high maximum throughput for its favorite traffic pattern where every transmission node sends data to its adjacent downstream node only.