5,082 research outputs found

    Cooperative Caching for Multimedia Streaming in Overlay Networks

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    Traditional data caching, such as web caching, only focuses on how to boost the hit rate of requested objects in caches, and therefore, how to reduce the initial delay for object retrieval. However, for multimedia objects, not only reducing the delay of object retrieval, but also provisioning reasonably stable network bandwidth to clients, while the fetching of the cached objects goes on, is important as well. In this paper, we propose our cooperative caching scheme for a multimedia delivery scenario, supporting a large number of peers over peer-to-peer overlay networks. In order to facilitate multimedia streaming and downloading service from servers, our caching scheme (1) determines the appropriate availability of cached stream segments in a cache community, (2) determines the appropriate peer for cache replacement, and (3) performs bandwidth-aware and availability-aware cache replacement. By doing so, it achieves (1) small delay of stream retrieval, (2) stable bandwidth provisioning during retrieval session, and (3) load balancing of clients' requests among peers

    Supporting disconnection operations through cooperative hoarding

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    Mobile clients often need to operate while disconnected from the network due to limited battery life and network coverage. Hoarding supports this by fetching frequently accessed data into clients' local caches prior to disconnection. Existing work on hoarding have focused on improving data accessibility for individual mobile clients. However, due to storage limitations, mobile clients may not be able to hoard every data object they need. This leads to cache misses and disruption to clients' operations. In this paper, a new concept called cooperative hoarding is introduced to reduce the risks of cache misses for mobile clients. Cooperative hoarding takes advantage of group mobility behaviour, combined with peer cooperation in ad-hoc mode, to improve hoard performance. Two cooperative hoarding approaches are proposed that take into account access frequency, connection probability, and cache size of mobile clients so that hoarding can be performed cooperatively. Simulation results show that the proposed methods significantly improve cache hit ratio and provides better support for disconnected operations compared to existing schemes

    Cooperative Caching Framework for Mobile Cloud Computing

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    Due to the advancement in mobile devices and wireless networks mobile cloud computing, which combines mobile computing and cloud computing has gained momentum since 2009. The characteristics of mobile devices and wireless network makes the implementation of mobile cloud computing more complicated than for fixed clouds. This section lists some of the major issues in Mobile Cloud Computing. One of the key issues in mobile cloud computing is the end to end delay in servicing a request. Data caching is one of the techniques widely used in wired and wireless networks to improve data access efficiency. In this paper we explore the possibility of a cooperative caching approach to enhance data access efficiency in mobile cloud computing. The proposed approach is based on cloudlets, one of the architecture designed for mobile cloud computing

    Reducing Latency by Clustering Based Index Services using Hybrid Cache in Ad Hoc Networks

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    An efficient index structure is presented to guide mobile clients to the - objects. The proposed broadcast scheduling and indexing is aimed at minimizing query access time and energy consumption of the clients when retrieving - objects through wireless channels . W e design and evaluate cooperative caching techniques to efficiently support data access in ad hoc networks. We first propose two schemes: Cache Data , which caches the data, and Cache Path , which caches the data path. After analyzing the performance of those two schemes, we propose a hybrid approach ( Hybrid Cache ), which can further improve the performance by taking advantage of Cache Data and Cache Path while avoiding their weaknesses. Cache replacement policies are also studied to further improve the performance. Simulation results show that the proposed schemes can signifi cantly reduce the query delay and message complexity when compared to other caching schemes

    Implementation and Evaluation of Mobile-Edge Computing Cooperative Caching

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    Recent expanding rise of mobile device users for cloud services leads to resource challenges in Mobile Network Operator's (MNO) network. This poses significant additional costs to MNOs and also results in poor user experience. Studies illustrate that large amount of traffic consumption in MNO's network is originated from the similar requests of users for the same popular contents over Internet. Therefore such networks suffer from delivering the same content multiple times through their connected gateways to the Internet backhaul. On the other hand, in content delivery networks (CDN), the delay caused by network latency is one of the biggest issues which impedes the efficient delivery and desirable user experience. Cooperative caching is one of the ways to handle the extra posed traffic by requesting popular contents repeatedly in MNO's network. Furthermore Mobile-Edge Computing (MEC) offers a resource rich environment and data locality to cloud applications. This helps to reduce the network latency time in CDN services. Thus in this Thesis an aggregation between Cooperative Caching and MEC concept has been considered. This Thesis demonstrates a design, implementation and evaluation for a Mobile-Edge computing Cooperative Caching system to deliver content to mobile users. A design is presented in a failure resilient and scalable practice using a light-weight synchronizing method. The system is implemented and deployed on Nokia Networks Radio Application Cloud Servers(Nokia Networks RACS) as intelligent MEC base-stations and finally the outcome of the system and the effect on bandwidth saving, CDN delay and user experience are evaluated
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