車輛內的乘客可將他的行動裝連接於車內的行動路由器上，此行動路由器可透過各種不同的無線通訊技術連接至網際網路上。但是高封包丟失率和低頻寬是無線傳輸環境下常見的問題。多鏈路行動網路架構於先前的研究中被提出，透過同時使用多條無線連結來改善可靠度及集合頻寬，並且可相容現今網際網路上使用傳輸控制協定(TCP)的主機。在這份研究中，我們提出一個創新的通訊協定，稱作多鏈路傳輸控制協定(Multi-homed TCP)。用來增進單一連線使用傳輸控制協定同時透過多條無線連結傳送資料流之效率。多鏈路傳輸控制協定由以下三項改進組成。首先，配置重排序緩衝來消除因封包亂序所造成不必要的資料重傳。接著多鏈路分割連線被用來使單一連線能快速地調適到同時使用多條連結的連線狀況，並且分別為每一條連結調整擁塞視窗。最後我們提出基於擁塞視窗之經排程的傳輸控制演算法，用來減輕在多鏈路環境中使用異質連結情況下所產生的負面影響。此外，我們透過與平行多路徑傳送之串流控制傳輸協定(CMT-SCTP)做比較來評估多鏈路傳輸控制協定效能上的進化。多鏈路傳輸控制協定解決數個在現實中會發生的效能議題，並且讓多鏈路的技術更加的具有可行性和實用性。

In an on-board network, passengers attach their mobile devices to an on-board Mobile Router (MR) which is connected to the Internet through various wireless access technologies. However, high packet loss rate and low bandwidth are commonly seen in a wireless environment. In prior work, a multi-homed NEMO architecture has been proposed to improve the reliability and aggregate the bandwidth by simultaneously using multiple wireless links, and is backward compatible with the TCP hosts in the Internet. In this work, we propose a novel protocol called MH-TCP (Multi-homed TCP) to improve the performance of TCP traffic for single connection over multiple wireless links. MH-TCP consists of three enhancements. First, the reordering buffer is deployed to eliminate unnecessary retransmission being caused by out-of-order packets. Second, Multi-homed Split Connection is used to make a single connection can quickly adapt to the conditions of multiple links and adjust the cwnd for each link accordingly. Finally, we proposed Scheduled Window-based Transmission Control algorithm to mitigate the negative effect of out-of-order packets in the cases of heterogeneous link in multi-homed environment. Further, we evaluate the evolutionary performance in MH-TCP according to compare with the Concurrent Multipath Transfer SCTP (CMT-SCTP). MH-TCP solved several performance issues that would happen in reality, and make the multi-homed technology more feasible and practicality.

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