隨著無線網路技術的發展，應用的層面也越來越廣泛，其中包含了車載之間的通訊應用。但在車輛隨意網路 (VANET) 通訊環境下，正確而可靠資料傳輸的困難度很高，傳輸延遲很大又難以預測，嚴重時更是會造成封包的遺失，故我們必須使用其他技術來提升傳輸效能。
在此車輛隨意網路的通訊環境好比容忍延遲網路 (Delay Tolerant Network) DTN 環境。故首先我們利用 DTN 包裹層協定 (Bundle Protocol) 的包裹持有權轉移(Custody Transfer) 技術來提升傳輸效能，並且針對各種可能發生的通訊錯誤設計回復機制 (Recovery Message)，減少不必要的開銷。其次我們將有使用包裹持有權轉移的協定與一般的TCP-SACK 在傳輸效能上做比較，發現在高錯誤率和高間歇性延遲環境下，使用包裹持有權轉移的效能比較好，以達到可靠又有效率的傳輸。
最後，我們著重於包裹層協定的可靠傳輸，包裹層協定本身的傳輸特性即是能提供可靠的資料傳輸，我們將其應用在目前車對車之間的通訊並探討在車輛隨意網路環境下可能遇到的問題，最後加以改進以提升通訊的穩定性。

For the rapid growth of the wireless networks, more and more applications are presented to the public nowadays. One of the issues is the communication in the VANET. However, correct and reliable data transmission is quite difficult in the VANET, and the delay of transmission is highly changeable and unpredictable. In the worse case, it could result in terrible packet losses. Thus, we have to utilize other mechanism to overcome the problem.
Therefore, the environment of VANET is similar to the one of Delay Tolerant Network (DTN) in some cases. Firstly, we utilize the custody transfer mechanism of Bundle Protocol to raise the performance of transmission, and design a recovery mechanism, recovery message, to all possible communication errors in order to reduce the unnecessary overheads. Secondly, we compare the performance of custody transfer mechanism with the general TCP-SACK mechanism using no custody transfer, and find that the performance of custody transfer is better than the other when at the environment of high error rate and highly intermittent connection to achieve reliable and efficient data transmission.
Lastly, we focus on the reliable transmission in bundle protocol, since the characteristic of Bundle Protocol provides reliable transmission. And we take it into the application to the communication between vehicles, discussing the problems we found in the VANET. Finally we solve them to make communication more stable.

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