Impact of layer 2 behavior on TCP performance in WLAN
Impact of layer 2 behavior on TCP performance in WLAN
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DOI：
10.1109/vetecf.2005.1558397
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发表时间：
2005-09
期刊：
影响因子：
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通讯作者：
K. Tsukamoto;R. Ijima;S. Kashihara;Y. Oie
中科院分区：
文献类型：
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作者：
K. Tsukamoto;R. Ijima;S. Kashihara;Y. Oie
能够在任何时间和任何位置由移动节点(MN)访问的泛在网络将由几个不同的无线局域网(WLAN)组成，因此MN很可能在通信期间穿越几个WLAN。在这种情况下，避免切换期间的性能下降成为一个关键问题。现有的大多数研究都是基于上层信息(如分组丢失)来处理切换决策，但没有一项研究广泛地研究了切换决策的标准以及在执行切换之前这些标准是如何影响性能下降的。在本文中，我们首先广泛地研究了在已有研究中所采用的切换决策准则下的TCP性能。然后，我们处理了第二层的行为，并提出了一种跨层的方法，使MN能够快速准确地感知无线链路的恶化，以避免切换期间的性能下降。最后，我们确定了MN的移动如何影响其WLAN的整体TCP性能以及其自身的TCP性能。通过仿真，我们证明了利用第二层信息可以有效地避免切换过程中的降级。
Ubiquitous networks enabling access by Mobile Nodes (MNs) at any time and at any location will consist of several different wireless LANs (WLANs), so it is likely that an MN will traverse several WLANs during communication. In such a case, avoiding performance degradation during the handoff becomes a critical issue. The majority of existing studies deal with handoff decisions based on upper layer information such as packet loss, but none of the studies extensively examine the criteria for a handoff decision and investigate how the criteria can affect the performance degradation just before the handoff is executed. In this paper, we first extensively investigate the TCP performance under the criteria for the handoff decision employed by existing studies. Then, we deal with Layer 2 behavior and suggest that a cross-layer approach, which enables an MN to perceive the deterioration of a wireless link quickly and exactly, is necessary to avoid the performance degradation during a handoff. Finally, we identify how the movement of the MN affects the overall TCP performance of its WLAN and its own TCP performance. Through simulations, we show that degradation during a handoff can effectively be avoided by exploiting Layer 2 information.