On a unified architecture for video-on-demand services

Abstract

Abstract-Current video-on-demand (VoD) systems can be classified into two categories: 1) true-VoD (TVoD) and 2) near-VoD (NVoD). TVoD systems allocate a dedicated channel for every user to achieve short response times so that the user can select what video to play, when to play it, and perform interactive VCR-like controls at will. By contrast, NVoD systems transmit videos repeatedly over multiple broadcast or multicast channels to enable multiple users to share a single video channel so that system cost can be substantially reduced. The tradeoffs are limited video selections, fixed playback schedule, and limited or no interactive control. TVoD systems can be considered as one extreme where service quality is maximized, while NVoD systems can be considered as the other extreme where system cost is minimized. This paper proposes a novel architecture called Unified VoD (UVoD) that can be configured to achieve cost-performance tradeoff anywhere between the two extremes (i.e., TVoD and NVoD). Assuming that a video client can concurrently receive two video channels and has local buffers for caching a portion of the video data, the proposed UVoD architecture can achieve significant performance gains (e.g., 400% more capacity for a 500-channel system) over TVoD under the same latency constraint. This paper presents the UVoD architecture, establishes a performance model, and analyzes UVoD's performance via numerical and simulation results.Index Terms-Near-video-on-demand (NVoD), performance analysis, true-video-on-demand (TVoD), unified architecture, UVoD, video-on-demand (VoD).

Channel folding - an algorithm to improve efficiency of multicast video-on-demand systems

“…In the previous work leading to this study, Lee [35] proposed and analyzed the unified video-on-demand (UVoD) architecture that integrated periodic broadcasting with patching. The UVoD architecture includes the traditional TVoD and NVoD as special cases of the architecture but generally outperforms them if properly configured.…”

“…Second, the total number of channels required to achieve the same latency as the original UVoD is reduced. Third, the near-optimal channel allocation derived by Lee [35] no longer holds, and a new channel partition policy is needed. We address these impacts in the following three sections.…”

“…Some of these novel approaches include batching [1]- [5], chaining [6], [7], periodic broadcasting [8]- [21], patching [22]- [26], and piggybacking [27]- [30]. These techniques are often complementary and hence can be combined into even more sophisticated architectures to further improve efficiency [31]- [35]. A more detailed review of these works will be presented in Section II.…”

“…In a previous study, Lee [35] presented and analyzed a unified video-on-demand (UVoD) architecture for building efficient large-scale VoD systems. The UVoD architecture integrates multicast with unicast to vastly reduce resource requirement at heavy loads.…”

Scheduled video delivery-a scalable on-demand video delivery scheme

“…The VoD service is attractive since it is selective and responsive [5]- [7]. With SVD, the selectivity is retained, but the responsiveness has been changed into a plan-ahead and guaranteed arrival.…”