提出了一种适用于多媒体传输的接收端驱动的分层多播拥塞控制机制,简称BDP(based on delay parameters)协议。该协议依据时延参数的动态变化来估测路径可用带宽,保证了网络资源的有效利用,实现了自适应的加层判断;预测网络的拥塞状况,...提出了一种适用于多媒体传输的接收端驱动的分层多播拥塞控制机制,简称BDP(based on delay parameters)协议。该协议依据时延参数的动态变化来估测路径可用带宽,保证了网络资源的有效利用,实现了自适应的加层判断;预测网络的拥塞状况,实现了对拥塞的快速响应。ns2仿真结果表明,BDP协议取得良好的稳定性、扩展性、快速收敛性,相比于现有的MRAAR-MT协议,BDP协议表现了更好的TCP公平性。展开更多
可用带宽是重要的网络资源,但实际测量却存在许多困难。基于Cruz流量模型和单向时延OWD(oneway delay)趋势分析,提出一种端到端的可用带宽主动测量算法PathPCQ(Path Parameter based on Cruz Queue)。PathPCQ通过主动检测OWD连续上升的...可用带宽是重要的网络资源,但实际测量却存在许多困难。基于Cruz流量模型和单向时延OWD(oneway delay)趋势分析,提出一种端到端的可用带宽主动测量算法PathPCQ(Path Parameter based on Cruz Queue)。PathPCQ通过主动检测OWD连续上升的概率,推断探测速率与端到端可用带宽之间的关系。当探测速率大于可用带宽时,其概率大于阈值;否则小于阈值。由此调整探测速率,使之逼近可用带宽。ns2仿真结果显示,PathPCQ算法测量精度和效率都优于现有的带宽测量工具Pathload,为网络资源管理、监控和预测提供了有益的手段。展开更多
With the rapid growth of wireless broadband technologies, such as WLAN and WiMAX, quality streaming video contents are available through portable devices anytime, anywhere. The layered multicast system using scalable ...With the rapid growth of wireless broadband technologies, such as WLAN and WiMAX, quality streaming video contents are available through portable devices anytime, anywhere. The layered multicast system using scalable video codecs has been proposed as an efficient architecture for video dissemination taking account of user and link diversities. However, in the wired/wireless combined best-effort based heterogeneous IP networks which provide more fluctuation in available bandwidth and end-to-end delay, the performance of streaming systems has been greatly degraded due to frequent packet loss, resulting from either wired congestion or wireless fading/shadowing. In this paper, we present a real-time embedded packet train probing scheme for estimating end-to-end available bandwidth so as to accomplish effective congestion and error control. This is facilitated by effective classification of packet loss sources, delay trend detection algorithm and flexible transmission rate of packets. Under the proper wireless channel modelling and estimation, our layered structure can allow appropriate subscription of video layers and adaptively insert necessary amount of forward error correction (FEC) packets so as to achieve QoS optimized system for scalable video multicasting.展开更多
文摘提出了一种适用于多媒体传输的接收端驱动的分层多播拥塞控制机制,简称BDP(based on delay parameters)协议。该协议依据时延参数的动态变化来估测路径可用带宽,保证了网络资源的有效利用,实现了自适应的加层判断;预测网络的拥塞状况,实现了对拥塞的快速响应。ns2仿真结果表明,BDP协议取得良好的稳定性、扩展性、快速收敛性,相比于现有的MRAAR-MT协议,BDP协议表现了更好的TCP公平性。
文摘可用带宽是重要的网络资源,但实际测量却存在许多困难。基于Cruz流量模型和单向时延OWD(oneway delay)趋势分析,提出一种端到端的可用带宽主动测量算法PathPCQ(Path Parameter based on Cruz Queue)。PathPCQ通过主动检测OWD连续上升的概率,推断探测速率与端到端可用带宽之间的关系。当探测速率大于可用带宽时,其概率大于阈值;否则小于阈值。由此调整探测速率,使之逼近可用带宽。ns2仿真结果显示,PathPCQ算法测量精度和效率都优于现有的带宽测量工具Pathload,为网络资源管理、监控和预测提供了有益的手段。
文摘With the rapid growth of wireless broadband technologies, such as WLAN and WiMAX, quality streaming video contents are available through portable devices anytime, anywhere. The layered multicast system using scalable video codecs has been proposed as an efficient architecture for video dissemination taking account of user and link diversities. However, in the wired/wireless combined best-effort based heterogeneous IP networks which provide more fluctuation in available bandwidth and end-to-end delay, the performance of streaming systems has been greatly degraded due to frequent packet loss, resulting from either wired congestion or wireless fading/shadowing. In this paper, we present a real-time embedded packet train probing scheme for estimating end-to-end available bandwidth so as to accomplish effective congestion and error control. This is facilitated by effective classification of packet loss sources, delay trend detection algorithm and flexible transmission rate of packets. Under the proper wireless channel modelling and estimation, our layered structure can allow appropriate subscription of video layers and adaptively insert necessary amount of forward error correction (FEC) packets so as to achieve QoS optimized system for scalable video multicasting.
