High Performance TCP Communication over Mobile IP Handoff

通过移动 IP 切换进行高性能 TCP 通信

• 批准号: 16560327
• 负责人: KUMEKAWA Kazuya
• 金额: $ 2.05万
• 依托单位: The University of Electro-Communications
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16560327/
• 关键词: Mobile IP; Handoff; TCP

Recently, the mobile communication environment is widely spread. An example is the 3rd generation cellular network, and the Mobile IP is adopted as one of the basic protocols for such a network. In the Mobile IP network environment, it is often the case that packet losses are caused by the transmission errors in wireless links and/or the handoff during terminal movement.In such an environment, TCP is also commonly used to access WWW servers and to transfer e-mail. However, the packet losses are described above invoke the congestion control function of TCP frequently, and as the result, the throughput of TCP communication over mobile environment is degraded heavily.So far, there have been a lot of studies for this problem, but most of them focus mainly on the packet losses caused by transmission errors. However, in the Mobile IP networks, the packet losses caused by handoff also invoke serious throughput degradation. In this research, we propose a TCP communication procedure improving the throughput even when there are packet losses caused by the Mobile IP handoff.Our procedure allows foreign agents to collectively work as a supervisor host in M-TCP procedure and to suspend TCP communication by making a correspondent node in persist mode. Our procedure also allows foreign agents to coordinate during the Mobile IP registration procedure and a home agent to restart the TCP communication immediately by sending a window update instead of the mobile node.We have also shown the performance evaluation by using modified ns-2 simulator. We have concluded that our procedure outperforms both the conventional TCP over Mobile IP and the "M-TCP over Mobile IP" i.e. foreign agents support only the original M-TCP functions without allowing home agent to send any window update, which is a part of our proposal.

最近，移动通信环境得到了广泛的普及。以第三代蜂窝网络为例，移动IP被用作该网络的基本协议之一。在移动IP网络环境中，经常会出现由于无线链路传输错误和/或终端移动过程中的切换而导致丢包的情况。在这样的环境中，TCP也通常用于访问WWW服务器和传输电子邮件。然而，上述丢包问题频繁调用TCP的拥塞控制功能，导致TCP在移动环境下的通信吞吐量严重下降。到目前为止，对这一问题的研究已经很多，但大多数研究主要集中在传输错误导致的丢包问题上。然而，在移动IP网络中，由切换引起的丢包也会导致严重的吞吐量降低。在本研究中，我们提出了一种TCP通信程序，即使在移动IP切换导致丢包的情况下，也能提高吞吐量。我们的过程允许外部代理在M-TCP过程中共同作为一个主管主机，并通过在持久模式下创建一个通信节点来暂停TCP通信。我们的过程还允许外部代理在移动IP注册过程中进行协调，并允许本地代理通过发送窗口更新而不是移动节点来立即重新启动TCP通信。我们还展示了使用改进的ns-2模拟器进行性能评估。我们的结论是，我们的程序优于传统的移动IP上的TCP和“移动IP上的M-TCP”，即外部代理只支持原始的M-TCP功能，而不允许本地代理发送任何窗口更新，这是我们建议的一部分。