Multi-party video conferencing (MPVC) is the next big opportunity for Internet streaming. Commercial MPVC solutions are either server-based or peer-to-peer (P2P)-based, which both have performance limitations. P2P technology is expected to dominate the MPVC platform. There are four requirements for a robust MPVC system: 1) realistic network assumptions; 2) realistic system settings; 3) multi-rate support; and 4) any-view support. Existing academic works study the problem from a theoretical perspective, and none of them meets all four requirements simultaneously. We design CoolConferencing, an overlay network for robust P2P MPVC. The core operations follow the easy-to-implement, robust, and resilient data-driven principle, which does not maintain complex global structures such as dissemination trees and can adapt to network dynamic distributedly and quickly. CoolConferencing is a robust system that meets all four requirements simultaneously. In addition, to the best of our knowledge, there is no existing work which examines its MPVC approach under various realistic network environments. We have evaluated CoolConferencing via an event-driven simulation. Compared with state-of-the-art video conferencing solutions, CoolConferencing achieves around 25% gain than Mutualcast and around 9% gain than Celerity in performance. Moreover, when the helper mechanism is enabled, CoolConferencing can easily exploit all available bandwidth to get optimal video transmission performance.

CoolConferencing: Enabling Robust Peer-to-Peer Multi-Party Video Conferencing

In Peer-to-Peer (P2P) video streaming systems, a stream of chunks is delivered from the source to all participant peers by utilizing upload bandwidth of the participants. The given stream is generally divided into several sub-streams and those sub-streams are delivered through different spanning trees. In this paper, we consider the delivery of a sub-streams to n subscribers through a spanning trees of depth two each. We call such a delivery of sub-streams a 2-hop delivery of the given video stream. The main contribution of the current paper is that it completely identifies a function Θ(a,n) such that the 2-hop delivery of a sub-streams to n subscribers is possible if and only if the upload bandwidth of each peer is at least Θ(a,n).

Tight Bounds for Two-Hop Delivery in Homogeneous P2P Video Streaming Systems

Cloud-Assisted Peer-to-Peer Video Streaming with Minimum Latency

This paper considers Peer-to-Peer (P2P) video streaming systems, in which a given video stream is divided into b stripes and those stripes are delivered to n peers through b spanning trees under the constraint such that each peer including the source can forward at most b stripes. The delivery of a stripe to n peers is said to be a k-hop delivery if all peers receive the stripe through a path of length at most k. Let Bk = ∑k−1 i=0 b i. It is known that under the above constraint, k-hop delivery of b stripes to n peers is possible only if n ≤ Bk . This paper proves that (k + 1)hop delivery of b stripes to n peers is possible for any n ≤ Bk; namely, we can realize the delivery of stripes with a guaranteed latency while it is slightly larger than the minimum latency. In addition, we derive a necessary and sufficient condition on n to enable a k-hop delivery of b stripes for Bk − b + 2 ≤ n ≤ Bk − 1; namely for n’s close to Bk . key words: P2P video streaming system, guaranteed latency, treestructured overlay

Multi-Tree-Based Peer-to-Peer Video Streaming with a Guaranteed Latency

In this paper, we propose a novel contribution-aware neighbor-assist video delivery solution over mobile content-centric network (CNVD). CNVD allows the nodes to build and maintain neighbor relationship with other nodes to share cached video resources and achieve unicast-based video lookup. CNVD constructs an estimation model of contribution of neighbor nodes by investigation of lookup delay, number of cached videos, lookup success rate, and geographical distance. CNVD designs the estimation methods of interest level and lookup capacity of nodes for video content, which enables the nodes to decide whether to build neighbor relationship with other nodes. A maintenance method of neighbor relationship between nodes is proposed, which enables the nodes to update valid time of neighbor relationship in terms of contribution of neighbor nodes and decide whether to remove neighbor relationship in terms of the current valid time of neighbor relationship. Further, CNVD designs a contribution-based video lookup algorithm, which reduces lookup delay and improves lookup success rate. Extensive tests show how CNVD achieves much better performance results in comparison with other state-of-the-art solutions.

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A Novel Contribution-Aware Neighbor-Assist Video Delivery Solution over Mobile Content-Centric Networks

Multiparty video conferencing (MPVC) facilitates real-time group interaction between users. While P2P is a natural delivery solution for MPVC, a peer often does not have enough bandwidth to deliver her video to all other peers in the conference. Recently, we have witnessed the popularity of one-view MPVC, where each user only watches full video of another user. One-view MPVC opens up the design space for P2P delivery. In this paper, we explore the feasibility of a pure P2P solution for one-view MPVC. We characterize the video source rate region achievable through video relays between peers. For both homogeneous and heterogeneous MPVC systems, we establish tight universal video rate lower bounds that are independent of the number of peers, the number of video sources, and the specific viewing relations between peers. We further propose, P2P video relay designs to approach the maximal video rate region. Through numerical simulations, we verified that the derived lower bounds are indeed tight bounds, and the proposed bandwidth allocation algorithm can achieve a close-to-optimal peer upload bandwidth utilization. Our results demonstrate that P2P is a promising solution for one-view MPVC. Insights obtained from our study can be used to guide the design of P2P MPVC systems.

/pdf/enabling-p2p-one-view-multiparty-video-conferencing-1dsmcpe3g6.pdf

Jianyin Zhang

Papers

Enabling P2P One-View Multiparty Video Conferencing