Research of Proxy Cache Algorithm in Multi-media Education System

Multi-media education system is more and more widely used in all levels of education. In order to decrease cost of multi-media system and keep efficiency with increasing multi-media materials, proxy cache algorithm has been widely studied. Based on analysis of existing research of proxy cache results, an improved proxy coaching strategy of prefix cache and postfix merging is proposed. The strategy can dynamically adjust prefix cache size with the object access change. A more effective method of steaming merging has been proposed with multicast used in postfix portion. The results show that the improved strategy can effectively utilize proxy cache resource, shorten time delay and save band width

Popularity-Based Adaptive Content Delivery Scheme with In-Network Caching

To solve the increasing popularity of video streaming services over the Internet, recent research activities have addressed the locality of content delivery from a network edge by introducing a storage module into a router. To employ in-network caching and persistent request routing, this paper introduces a hybrid content delivery network (CDN) system combining novel content routers in an underlay together with a traditional CDN server in an overlay. This system first selects the most suitable delivery scheme (that is, multicast or broadcast) for the content in question and then allocates an appropriate number of channels based on a consideration of the content’s popularity. The proposed scheme aims to minimize traffic volume and achieve optimal delivery cost, since the most popular content is delivered through broadcast channels and the least popular through multicast channels. The performance of the adaptive scheme is clearly evaluated and compared against both the multicast and broadcast schemes in terms of the optimal in-network caching size and number of unicast channels in a content router to observe the significant impact of our proposed scheme

Managing video objects in large peer-to-peer systems

In peer-to-peer video systems, most hosts will retain only a small portion of a video after its playback. This presents two challenges in managing video data in such systems: (1) how a host can find enough video pieces, which may scatter among the whole system, to assemble a complete video, and (2) given a limited buffer size, what part of a video a host should cache. In this thesis, we address these problems with a new distributive file management technique. In our scheme, we organize hosts into many cells, each of which is a distinct set of hosts which together can supply a video in its entirety. Because each cell is dynamically created and individually managed as an independent video supplier, our technique addresses the two problems, video lookup and caching, simultaneously. First, a client looking for a video can stop its search as soon as it finds a host that caches any part of the video. This dramatically reduces the search scope of a video lookup. Second, caching operations can now be coordinated within each cell to balance data redundancy in the system. We have implemented a Gnutella-like simulation network and use it as a testbed to evaluate the proposed technique. Our extensive study shows convincingly the performance advantage of the new scheme

Novel Proactive Patch Peer Protocol to Support Faster Delivery of Video-on-Demand

© ASEE 2011An important feature in the convergence of network is provision of multimedia applications. Multimedia consists of different classes but video-on-demand (VoD) has been more focusing research area in recent years. VoD enables the users to watch and select the contents of songs and movies on demand. There is still no concrete technique to attain the goals of delivering the video on demand fastly. Secondly the delivery of video on demand to heterogeneous mobile environment is very exigent task because multimedia services face various limitations mostly caused by the wireless channel unpredictability, limited bandwidth, assorted behavior of protocols, standards and fading effect, etc. The users mostly face the issues of downloading the on-line applications and data by using VoD method on heterogamous networks. To reduce these problems, we propose and simulate the novel technique of proactive patch peer (PPP) protocol to support the delivery of VoD. This protocol gets the peer from server and requests the remaining part (patch) for playing the video from one distance neighbour node on the basis of stored information for one hop distance of node onto the profile of requesting nodes. The protocol uses unicast scheme to reduce the network traffic load and avoid the bottleneck. The other features of PPP are to save the bandwidth and make the faster delivery of video on demand as compare with other previous techniques. We first present the concept and architecture of PPP, and then introduce used techniques for unicast VoD method. We also target and evaluate the multicasting issues for delivery of VoD. Our experimental results demonstrate on the basis of simulation that the proposed PPP is more effective, faster and bandwidth saving protocol for delivery of VoD

Cooperative Interval Caching in Clustered Multimedia Servers

In this project, we design a cooperative interval caching (CIC) algorithm for clustered video servers, and evaluate its performance through simulation. The CIC algorithm describes how distributed caches in the cluster cooperate to serve a given request. With CIC, a clustered server can accommodate twice (95%) more number of cached streams than the clustered server without cache cooperation. There are two major processes of CIC to find available cache space for a given request in the cluster: to find the server containing the information about the preceding request of the given request; and to find another server which may have available cache space if the current server turns out not to have enough cache space. The performance study shows that it is better to direct the requests of the same movie to the same server so that a request can always find the information of its preceding request from the same server. The CIC algorithm uses scoreboard mechanism to achieve this goal. The performance results also show that when the current server fails to find cache space for a given request, randomly selecting a server works well to find the next server which may have available cache space. The combination of scoreboard and random selection to find the preceding request information and the next available server outperforms other combinations of different approaches by 86%. With CIC, the cooperative distributed caches can support as many cached streams as one integrated cache does. In some cases, the cooperative distributed caches accommodate more number of cached streams than one integrated cache would do. The CIC algorithm makes every server in the cluster perform identical tasks to eliminate any single point of failure, there by increasing availability of the server cluster. The CIC algorithm also specifies how to smoothly add or remove a server to or from the cluster to provide the server with scalability

Novel Techniques for Large-Scale and Cost-Effective Video Services

Despite the advance of network technologies in the past decade, providing video services to a large number of users remains a major technical challenge. This is especially true when it comes to serving high-definition videos. This thesis makes two contributions towards providing large-scale and cost-effective video services. 1) We consider the problem of periodic broadcast of popular videos in client/server video systems and present two novel techniques. Our research advances the state of the art with a segmentation rule that can generate a series of broadcast designs, among which we can choose the one that results in the smallest broadcast latency. We show that this rule allows us to design the broadcast technique that is the fastest up to date. 2) We then look at the problem of service scheduling in fully distributed peer-to-peer video systems, where a large number of hosts collaborate for the purpose of video sharing. Our proposed technique allows a client to be served by a server that is beyond its own file look up scope and can dynamically adjust client and server matches as new video requests arrive in the system. Our performance evaluation shows that these features dramatically improve the system performance to a large extent in terms of reducing service latency under a range of simulation settings

Best-Effort Patching for Multicast True VoD Service

A multicast Video-on-Demand (VoD) system allows clients to share a server stream by batching their requests, and hence, improves channel utilization. However, it is very difficult to equip such a VoD system with full support for interactive VCR functions which are important to a growing number of Internet applications. In order to eliminate service (admission) latency, patching was proposed to enable an existing multicast session to dynamically add new clients, and requests can be served without delay if patching channels are available. A true VoD (TVoD) service should support not only zero-delay client admission but also continuous VCR-like interactivity. However, the conventional patching is only suitable for admission control. We propose a new patching scheme, called Best-Effort Patching (BEP), that offers a TVoD service in terms of both request admission and VCR interactivity. Moreover, by using a novel dynamic merging algorithm, BEP significantly improves the efficiency of TVoD interactivity, especially for popular videos. We also model and evaluate the efficiency of the dynamic merging algorithm. It is shown that BEP outperforms the conventional TVoD interaction protocols.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47328/1/11042_2005_Article_6851.pd