Abstract: In order to solve the receive buffer blocking in concurrent multipath transfer, this paper analyzes the reason for receive buffer blocking and proposes an improved packet scheduling method. Considering bandwidth, delay and packet loss rate, the method introduces the evaluation function of the path quality, with which it optimizes the packet scheduling algorithm. By transmitting packets through the path with best quality, it reduces the number of packets out of order caused by different path characteristics. Based on delay and packet loss rate, it also proposes an improved retransmission policy, which selects the fastest path to the receiver to retransmit the lost packets. It puts forward a method to estimate the size of receive buffer according to the bandwidth delay product of paths. The experimental results show that the packet scheduling method and the retransmission policy proposed can reduce receive buffer blocking effectively, which is better than CMT-SCTP. And the simulation also indicates that the estimation method can evaluate the desired receive buffer size accurately.

Key words: concurrent multipath transfer, receive buffer blocking, retransmission policy, congestion window

摘要： 针对多通道并行传输中的接收缓存阻塞问题，分析了引起接收缓存阻塞的原因，提出一种改进的缓解接收缓存阻塞的数据包调度方法，综合考虑通道的带宽、时延和丢包率，引入通道质量的评价函数，优化多通道之间的数据包调度，选择质量最好的通道进行传输，减少由于通道特性不同造成的接收端数据包乱序；提出一种改进的数据包重传策略，基于时延和丢包率选择能使数据包最快到达接收端的通道进行重传；提出一种根据通道的带宽—延迟积估算所需接收缓存大小的方法。仿真实验表明，所提出的调度方法和重传策略能够有效地减轻接收缓存阻塞，与CMT-SCTP相比具有更优的性能，所提出的缓存大小的估算方法也能够准确估算所需接收缓存的大小。

关键词: 多通道并行传输, 接收缓存阻塞, 重传策略, 拥塞窗口