I-Swifter: Improving chunked network coding for peer-to-peer content distribution

Abstract

Network coding has been proposed as a promising approach for peer-to-peer content distribution in recent literature. Not only reducing the average download time, but also improving resilience to peer churn has been showed as the benefits brought by network coding. State-of-the-art network coding content distribution systems perform network coding within segments or chunks, in order to reduce computational overhead. In our previous work (Xu et al. 2008), we proposed to schedule segment requests at a localrarest-first basic. Local-rarest-first segment scheduling, as we demonstrated, is superior to the random scheduling. In this paper, we make a further step towards improving chunked network coding content distribution systems. We propose a requests reducer that reduces the overhead in control traffic and an encoding vectors reducer that eliminates the transmission of encoding vectors. Our contributions are to save unnecessary requests from downstream peers, and to reduce encoding vectors payload when the upstream peer owns the complete requested segment. This paper presents a realistic implementation, named I-Swifter. And we also make a comparative study on various related implementations. Experimental results show that there is about 10-20% of encoding vectors can be saved in I-Swifter. Moreover, I-Swifter improves average and maximum download time, the server load as well.

TRANSIT: Supporting transitions in Peer-to-Peer live video streaming

“…Network coding techniques allow to save bandwidth at the cost of computational overhead by aggregating messages as a combination of the initial packets. By making the parameters of the combination and the aggregated message known at the receiver side, the packets can be decoded [25]. In future work, it will be investigated how network coding can be used as a further mechanism to allow for transitions to such schemes when bandwidth gets scarce.…”

Survey of Network Coding Based P2P File Sharing in Large Scale Networks

“…After the appearance of Avalanche and the associated issues, generation-based network coding [61], also known as grouped [23], chunked [62], segmented [63], or clustered [64], is proposed. In such a scheme, the file is segmented into groups where each group contains a mutually exclusive subset of the overall pieces; afterwards, network coding is applied per group only.…”

Survey of Network Coding Based P2P File Sharing in Large Scale Networks

“…Since Swifter is a pull-based scheme, it still incurs moderate control messages overhead. J. Xu et al [62] propose an improved Swifter, denoted by I-Swifter, in an attempt to improve generation-based network coding by reducing the control messages overhead and eliminating the distribution of encoding vectors. The architecture of I-Swifter is based on the architecture of Swifter, and hence, it inherits Swifter components and adds two new elements: the requests reducer that lowers the requesting overhead, and the coefficients' vectors reducer that stops the distribution of encoding vectors.…”