Skyscraper broadcasting: a new broadcasting scheme for metropolitan video-on-demand systems
01 Oct 1997-Vol. 27, Iss: 4, pp 89-100
TL;DR: This study investigates a novel multicast technique, called Skyscraper Broadcasting (SB), for video-on-demand applications, and is able to achieve the low latency of PB while using only 20% of the buffer space required by PPB.
Abstract: We investigate a novel multicast technique, called Skyscraper Broadcasting (SB), for video-on-demand applications. We discuss the data fragmentation technique, the broadcasting strategy, and the client design. We also show the correctness of our technique, and derive mathematical equations to analyze its storage requirement. To assess its performance, we compare it to the latest designs known as Pyramid Broadcasting (PB) and Permutation-Based Pyramid Broadcasting (PPB). Our study indicates that PB offers excellent access latency. However, it requires very large storage space and disk bandwidth at the receiving end. PPB is able to address these problems. However, this is accomplished at the expense of a larger access latency and more complex synchronization. With SB, we are able to achieve the low latency of PB while using only 20% of the buffer space required by PPB.
Citations
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19 Oct 2003
TL;DR: Unlike the Web, whose workload is driven by document change, it is demonstrated that clients' fetch-at-most-once behavior, the creation of new objects, and the addition of new clients to the system are the primary forces that drive multimedia workloads such as Kazaa.
Abstract: Peer-to-peer (P2P) file sharing accounts for an astonishing volume of current Internet traffic. This paper probes deeply into modern P2P file sharing systems and the forces that drive them. By doing so, we seek to increase our understanding of P2P file sharing workloads and their implications for future multimedia workloads. Our research uses a three-tiered approach. First, we analyze a 200-day trace of over 20 terabytes of Kazaa P2P traffic collected at the University of Washington. Second, we develop a model of multimedia workloads that lets us isolate, vary, and explore the impact of key system parameters. Our model, which we parameterize with statistics from our trace, lets us confirm various hypotheses about file-sharing behavior observed in the trace. Third, we explore the potential impact of locality-awareness in Kazaa.Our results reveal dramatic differences between P2P file sharing and Web traffic. For example, we show how the immutability of Kazaa's multimedia objects leads clients to fetch objects at most once; in contrast, a World-Wide Web client may fetch a popular page (e.g., CNN or Google) thousands of times. Moreover, we demonstrate that: (1) this "fetch-at-most-once" behavior causes the Kazaa popularity distribution to deviate substantially from Zipf curves we see for the Web, and (2) this deviation has significant implications for the performance of multimedia file-sharing systems. Unlike the Web, whose workload is driven by document change, we demonstrate that clients' fetch-at-most-once behavior, the creation of new objects, and the addition of new clients to the system are the primary forces that drive multimedia workloads such as Kazaa. We also show that there is substantial untapped locality in the Kazaa workload. Finally, we quantify the potential bandwidth savings that locality-aware P2P file-sharing architectures would achieve.
941Â citations
Cites background from "Skyscraper broadcasting: a new broa..."
...VoD researchers frequently use Zipf distributions to model the popularity of video documents in their systems [10, 18, 31]....
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01 Sep 1998
TL;DR: This paper is able to tiate the service latency and improve the efficiency of mtiticast at the same time, and indicates convincingly that Patching offers .wbstanti~y better perforrnace.
602Â citations
Additional excerpts
...Another approach is called Periodic Broadcast [16, 17, 18, 19]....
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Patent•
01 Apr 2011TL;DR: In this paper, the authors present a system that provides real-time or near-real-time streaming of content, specified in one or more playlists, using transfer protocols such as an HTTP compliant protocol.
Abstract: Methods and apparatuses provide real-time or near real-time streaming of content, specified in one or more playlists, using transfer protocols such as an HTTP compliant protocol. In one embodiment, a method can execute a user application on a client device to present media files and to control presentation of the media files. The method can further run a media serving process on the client device to retrieve a playlist specifying the media files and a media source at which the media files are available, to retrieve the media files from the media source, and to decode the media files retrieved. The media serving process can call the user application to process a custom URL in order to obtain an object referred to by the custom URL.
360Â citations
02 Jul 2002
TL;DR: A distributed differentiated admission control protocol DAC/sub p2p/ achieves fast system capacity amplification; benefits all requesting peers in admission rate, waiting time, and buffering delay; and creates an incentive for peers to offer their truly available out-bound bandwidth.
Abstract: In this paper, we study a peer-to-peer media streaming system with the following characteristics: (1) its streaming capacity grows dynamically; (2) peers do not exhibit server-like behavior; (3) peers are heterogeneous in their bandwidth contribution; and (4) each streaming session may involve multiple supplying peers. Based on these characteristics, we investigate two problems: (1) how to assign media data to multiple supplying peers in one streaming session and (2) how to quickly amplify the system's total streaming capacity. Our solution to the first problem is an optimal media data assignment algorithm OTS/sub p2p/, which results in minimum buffering delay in the consequent streaming session. Our solution to the second problem is a distributed differentiated admission control protocol DAC/sub p2p/. By differentiating between requesting peers with different outbound bandwidth, DAC/sub p2p/ achieves fast system capacity amplification; benefits all requesting peers in admission rate, waiting time, and buffering delay; and creates an incentive for peers to offer their truly available out-bound bandwidth.
286Â citations
Cites methods from "Skyscraper broadcasting: a new broa..."
...(5)The CBR media data model has been used in earlier works on media broadcasting [7]....
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01 Jan 1999
TL;DR: In this article, the authors compared the performance of the partitioned dynamic skyscraper and hierarchical multicast stream merging (HMSM) over a wide range of client request rates.
Abstract: Two recent techniques for multicast or broadcast delivery of streaming media can provide immediate service to each client request, yet achieve considerable client stream sharing which leads to significant server and network bandwidth savings. The paper considers: 1) how well these recently proposed techniques perform relative to each other and 2) whether there are new practical delivery techniques that can achieve better bandwidth savings than the previous techniques over a wide range of client request rates. The principal results are as follows: First, the recent partitioned dynamic skyscraper technique is adapted to provide immediate service to each client request more simply and directly than the original dynamic skyscraper method. Second, at moderate to high client request rates, the dynamic skyscraper method has required server bandwidth that is significantly lower than the recent optimized stream tapping/patching/controlled multicast technique. Third, the minimum required server bandwidth for any delivery technique that provides immediate real-time delivery to clients increases logarithmically (with constant factor equal to one) as a function of the client request arrival rate. Furthermore, it is (theoretically) possible to achieve very close to the minimum required server bandwidth if client receive bandwidth is equal to two times the data streaming rate and client storage capacity is sufficient for buffering data from shared streams. Finally, we propose a new practical delivery technique, called hierarchical multicast stream merging (HMSM), which has a required server bandwidth that is lower than the partitioned dynamic skyscraper and is reasonably close to the minimum achievable required server bandwidth over a wide range of client request rates.
285Â citations
References
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IBM1
TL;DR: It is shown that an FCFS policy that schedules the movie with the longest outstanding request can perform better than the MQL policy that chooses the film with the maximum number of outstanding requests.
Abstract: In an on-demand video server environment, clients make requests for movies to a centralized video server. Due to the stringent response time requirements, continuous delivery of a video stream to the client has to be guaranteed by reserving sufficient resources required to deliver a stream. Hence there is a hard limit on the number of streams that can be simultaneously delivered by a server. The server can satisfy multiple requests for the same movie using a single disk I/O stream by sending the same data pages to multiple clients (using the multicast facility if present in the system). This can be achieved by batching requests for the same movie that arrive within a short duration of time. In this paper, we consider various policies for selecting the movie to be multicast. The choice of a policy depends very much on the customer waiting time tolerance before reneging. We show that an FCFS policy that schedules the movie with the longest outstanding request can perform better than the MQL policy that chooses the movie with the maximum number of outstanding requests. Additionally, if the user behavior can be influenced by guaranteeing maximum waiting time then it may be beneficial to pre-allocate a fixed number of streams for popular movies. Finally, we demonstrate using empirical distribution for movie requests, that a substantial reduction (of the order of 60%) in required server capacity can be achieved by batching.
712Â citations
TL;DR: This paper provides analytical and experimental evaluations of pyramid broadcasting based on its implementation on an Ethernet LAN, gaining a radical improvement in access time and bandwidth use by using storage at the receiving end.
Abstract: Pyramid broadcasting is a new way of giving video-on-demand service on a metropolitan scale We multiplex the most frequently requested movies on the network, gaining a radical improvement in access time and bandwidth use This is achieved by using storage at the receiving end As the available bandwidth increases, the improvement in access time is exponential instead of linear as in conventional broadcasting The larger the bandwidth of the network is, the better gain in the access time due to pyramid broadcasting As the access-time requirement decreases, the bandwidth in conventional broadcasting increases linearly, while the bandwidth in pyramid broadcasting increases only logarithmically We provide analytical and experimental evaluations of pyramid broadcasting based on its implementation on an Ethernet LAN
496Â citations
TL;DR: It is shown that a first come, first served (FCFS) policy that schedules the video with the longest outstanding request can perform better than the maximum queue length (MQL) policy, and multicasting is better exploited by scheduling playback of the most popular videos at predetermined, regular intervals (hence, termed FCFS-n).
Abstract: In a video-on-demand environment, continuous delivery of video streams to the clients is guaranteed by sufficient reserved network and server resources. This leads to a hard limit on the number of streams that a video server can deliver. Multiple client requests for the same video can be served with a single disk I/O stream by sending (multicasting) the same data blocks to multiple clients (with the multicast facility, if present in the system). This is achieved by batching (grouping) requests for the same video that arrive within a short time. We explore the role of customerwaiting time and reneging behavior in selecting the video to be multicast. We show that a first come, first served (FCFS) policy that schedules the video with the longest outstanding request can perform better than the maximum queue length (MQL) policy that chooses the video with the maximum number of outstanding requests. Additionally, multicasting is better exploited by scheduling playback of the n most popular videos at predetermined, regular intervals (hence, termed FCFS-n). If user reneging can be reduced by guaranteeing that a maximum waiting time will not be exceeded, then performance of FCFS-n is further improved by selecting the regular playback intervals as this maximum waiting time. For an empirical workload, we demonstrate a substantial reduction (of the order of 60%) in the required server capacity by batching.
409Â citations
IBM1
TL;DR: This report is a tutorial aimed at providing the reader with background information that is necessary to understand the debate about potential virtues and shortcomings of the ATM.
Abstract: The Asynchronous Transfer Mode (ATM) is the switching and multiplexing technique chosen by CCITT for the broadband access to the ISDN. The user-network interface offers one physical channel over which connections are multiplexed using short, fixed length packets (called cells). The ATM layer in the network performs relaying functions, with every cell carrying a label used for switching. This report is a tutorial. It aims at providing the reader with background information that is necessary to understand the debate about potential virtues and shortcomings of the ATM.
326Â citations
"Skyscraper broadcasting: a new broa..." refers methods in this paper
...To address the network-I/O bottleneck faced by the user-centered approach, the multicast facility of modern communication networks [5, 13, 11, 17] can be used to allow users to share a server stream....
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17 Jun 1996
TL;DR: This study proposes a batching policy that schedules the video with the maximum factored queue length and shows that MFQ yields excellent empirical results in terms of standard performance measures such as average latency time, defection rates and fairness.
Abstract: In a video-on-demand environment, batching of video requests is often used to reduce I/O demand and improve throughput. Since viewers may defect if they experience long waits, a good video scheduling policy needs to consider not only the batch size but also the viewer defection probabilities and wait times. Two conventional scheduling policies for batching are first-come-first-served (FCFS) and maximum queue length (MOL). Neither of these policies lead to entirely satisfactory results. MQL tends to be too aggressive in scheduling popular videos by only considering the queue length to maximize batch size, while FCFS has the opposite effect. We introduce the notion of factored queue length and propose a batching policy that schedules the video with the maximum factored queue length. We refer to this as the MFQ policy. The factored queue length is obtained by weighting each video queue length with a factor which is biased against the more popular videos. An optimization problem is formulated to solve the best weighting factors for the various videos. A simulation is developed to compare the proposed MFQ policy with FCFS and MQL. Our study shows that MFQ yields excellent empirical results in terms of standard performance measures such as average latency time, defection rates and fairness.
307Â citations
"Skyscraper broadcasting: a new broa..." refers background in this paper
...Nev-ertheless, it was also shown in [7,8] that the popularities of movies follow the Zipf distribution with the skew fac- tor of 0.271, That is, most of the demand (80...
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