AngelCast: cloud-based peer-assisted live streaming using optimized multi-tree construction

Increasingly, commercial content providers (CPs) offer streaming solutions using peer-to-peer (P2P) architectures, which promises significant scalabil- ity by leveraging clients’ upstream capacity. A major limitation of P2P live streaming is that playout rates are constrained by clients’ upstream capac- ities – typically much lower than downstream capacities – which limit the quality of the delivered stream. To leverage P2P architectures without sacri- ficing quality, CPs must commit additional resources to complement clients’ resources. In this work, we propose a cloud-based service AngelCast that enables CPs to complement P2P streaming. By subscribing to AngelCast, a CP is able to deploy extra resources (angel), on-demand from the cloud, to maintain a desirable stream quality. Angels do not download the whole stream, nor are they in possession of it. Rather, angels only relay the minimal fraction of the stream necessary to achieve the desired quality. We provide a lower bound on the minimum angel capacity needed to maintain a desired client bit-rate, and develop a fluid model construction to achieve it. Realizing the limitations of the fluid model construction, we design a practical multi- tree construction that captures the spirit of the optimal construction, and avoids its limitations. We present a prototype implementation of AngelCast, along with experimental results confirming the feasibility of our service.Supported in part by NSF awards #0720604, #0735974, #0820138, #0952145, #1012798 #1012798 #1430145 #1414119. (0720604 - NSF; 0735974 - NSF; 0820138 - NSF; 0952145 - NSF; 1012798 - NSF; 1430145 - NSF; 1414119 - NSF

Application behavior and performance on asymmetrical links

Projecte final de carrera ralitzat en col.laboració amb Lund University. Faculty of EngineeringNowadays most of the access networks have asymmetrical bit rates; these networks (especially mobile networks) have high delays, packet losses and most often non neglectable jitter. In this degree project, we have studied the behavior of several different types of access networks with asymmetrical conditions. We have worked with the Kaunet deterministic network emulator to achieve practical results of these access networks. With the network emulator we have created different types of asymmetrical traffic data. The applications we have studied are Skype (voice/data in real time), web browsing (HTTP), TVUPlayer (P2P-TV), Bit Torrent (P2P sharing data) and data transmission in FTP. We analyzed how the protocols and the applications behaved in a theoretical way and then we tested them in a practical way with Kaunet. We studied how asymmetries affect delay times, packet losses and jitter introduced in the network and for each application we gave boundaries for a good performance for the mentioned parameters. Furthermore we analyzed bottlenecks and tried to minimize them. Finally, we compared the data from the different types of generated traffic and made some conclusions about the behavior of these applications in an asymmetrical environment

Localising Peers in P2P Live Streaming Systems Within Resource-Constrained Networks

The use of locality within peer-to-peer (P2P) networks is showing promise, ensuring the construction of overlay networks that are both economically viable for network operators and scalable, ensuring the successful delivery of content. However, the underlying protocols on which P2P overlays are based were originally designed as a best-effort, non-real time transfer medium which is now rapidly having to evolve in order to better support more time sensitive, real-time video delivery systems. This shift places greater demand on locality mechanisms to ensure the correct balance between bandwidth savings and successful timely playback. In this paper, we continue our work to resolve the strong trade-off resulted from the limited network condition in order to support efficient P2P live streaming services. Based on our findings we propose an OPLoc framework for supporting locality and harmonised play points in a live streaming P2P system. We present our results and analysis of its operation through a series of simulations which measure bandwidth consumption at network egress points, failure rates and each peers’ play point relative to the live stream

Serving Niche Video-on-Demand Content in a Managed P2P Environment

A limitation of existing P2P VoD services is their inability to support efficient streamed access to niche content that has relatively small demand. This limitation stems from the poor performance of P2P when the number of peers sharing the content is small. In this paper, we propose a new provider-managed P2P VoD framework for efficient delivery of niche content based on two principles: reserving small portions of peers' storage and upload resources, as well as using novel, weighed caching techniques. We demonstrate through analytical analysis, simulations, and experiments on planetlab that our architecture can provide high streaming quality for niche content. In particular, we show that our architecture increases the catalog size by up to $40\%$ compared to standard P2P VoD systems, and that a weighted cache policy can reduce the startup delay for niche content by a factor of more than three

Business model with discount incentive in a P2P-cloud multimedia streaming system

Today P2P faces two important challenges: design of mechanisms to encourage users' collaboration in multimedia live streaming services; design of reliable algorithms with QoS provision, to encourage the multimedia providers employ the P2P topology in commercial live streaming systems. We believe that these two challenges are tightly-related and there is much to be done with respect. This paper analyzes the effect of user behavior in a multi-tree P2P overlay and describes a business model based on monetary discount as incentive in a P2P-Cloud multimedia streaming system. We believe a discount model can boost up users' cooperation and loyalty and enhance the overall system integrity and performance. Moreover the model bounds the constraints for a provider's revenue and cost if the P2P system is leveraged on a cloud infrastructure. Our case study shows that a streaming system provider can establish or adapt his business model by applying the described bounds to achieve a good discount-revenue trade-off and promote the system to the users