Real-time Media Transmission Strategy And Congestion Control Strategy Research For POF-CCN

CCN is content-centric, and has lots of advantages in content distribution. SDN separates control plane from data plane, and makes it easy to configure the network. POF proposed by Huawei improves the programmability of SDN further. Accordingly, we propose a POF-CCN network architecture. CCN has unique advantages in video transmission. Currently real-time media transmission schemes in CCN mostly lack integrity. These schemes did not pay attention to persistent feature of real-time media transmission, and the use of traditional request mode in CCN will inevitably lead to a waste of resources. In addition, as a new network infrastructure, congestion control research is very necessary. Congestion control strategies in CCN mostly used implicit congestion control method, which means using round-trip delay for congestion judgment. Because there isn’t connection status in CCN and returned data packets are always from multiple sources, congestion judgments using RTT are not accurate.Considering the problems of current real-time media transmission schemes in CCN, this article proposes a scheme which makes a distinction between real-time media data and general data. This article details the scheme, including naming, content routing forwarding process, forwarding rules design. We design the sending and receiving programs using VLC and libpcap, and transfer media data over POF-CCN.As for inaccuracy of implicit congestion control strategies, this article proposes a congestion control strategy based on explicit feedback, with different values representing different network congestion situations. POF-CCN nodes predict network congestion based on queue length of interest packets, and mark congestion values in Interest packets. If congestion is detected, congestion values will be timely sent back to the data receivers. Receivers adjust congestion window size according to the degree of congestion. The nodes in the network allocate bandwidth fairly, and shape the interest queues in accordance with the congestion value.The scheme proposed by this article which makes a distinction between real-time media data and general data transfer has been successfully deployed in POF-CCN. Experiments show that the scheme can reduce network transmission pressure. The scheme has certain reference for researches of different types of contents transfer in CCN. In addition, The experimental results show that our joint congestion control scheme works well and has some reference value for congestion control researches in CCN.