| 1. |
- Du, Manxing, et al.
(författare)
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Analysis of prefetching schemes for TV-on-Demand service
- 2015
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Ingår i: ICDT 2015. - 9781612083964 ; , s. 12-18
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Konferensbidrag (refereegranskat)abstract
- TV-on-Demand service has become one of the most popular Internet applications that continuously attracts higher user interests. With rapidly increasing user demand, the existing network conditions may not be able to ensure low start-up delay of video playback. Prefetching has been broadly investigated to cope with the start-up latency problem which is also known as user perceived latency. In this paper, we analyse request patterns for TV programs from a popular Swedish TV service provider over 11 weeks. According to the analysis, we propose a prefetching scheme at the user end to preload videos before user requests. Our prefetching scheme significantly improves the cache hit ratio compared to terminal caching and we note that there is a potential to further improve prefetching performance by customizing prefetching schemes for different video categories. We further present a cost model to determine the optimal number of videos to prefetch. Finally, we discuss available time for prefetching and suggest that when to make prefetching decisions depends on the user demand patterns of different video categories.
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| 2. |
- Du, Manxing, et al.
(författare)
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Prefetching Schemes and Performance Analysis for TV on Demand Services
- 2015
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Ingår i: International Journal on Advances in Telecommunications. - 1942-2601. ; 8:3&4, s. 162-172
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Tidskriftsartikel (refereegranskat)abstract
- TV-on-Demand services have become one of the most popular Internet applications that continuously attracts high user interest. With rapidly increasing user demands, the existing network conditions may not be able to ensure a low start-up delay of video playback. Prefetching has been broadly investigated to cope with the start-up latency problem, which is also known as user perceived latency. In this paper, two datasets from different IPTV providers are used to analyse the TV program request patterns. According to the results, we propose a prefetching scheme at the user end to preload videos before user requests. For both datasets, our prefetching scheme significantly improves the cache hit ratio compared to passive caching and we note that there is a potential to further improve prefetching performance by customizing prefetching schemes for different video categories. We further present a cost model to determine the optimal number of videos to prefetch. We also discuss if there is enough time for prefetching. Finally, more factors, which may have an impact on optimizing prefetching performance, are further discussed, such as the jump patterns over different time in a day and the the distribution of each video’s viewing length.
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| 3. |
- Kihl, Maria, et al.
(författare)
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Analysis of facebook content demand patterns
- 2014
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Ingår i: 2014 International Conference on Smart Communications in Network Technologies, SaCoNeT 2014. - 9781479951963
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Konferensbidrag (refereegranskat)abstract
- Data volumes in communication networks increase rapidly. Further, usage of social network applications is very wide spread among users, and among these applications, Facebook is the most popular. In this paper, we analyse user demands patterns and content popularity of Facebook generated traffic. The data comes from residential users in two metropolitan access networks in Sweden, and we analyse more than 17 million images downloaded by almost 16,000 Facebook users. We show that the distributions of image popularity and user activity may be described by Zipf distributions which is favourable for many types of caching. We also show that Facebook activity is more evenly spread over the day, compared to more defined peak hours of general Internet usage. Looking at content life time, we show that profile pictures have a relatively constant popularity while for other images there is an initial, short peak of demand, followed by a longer period of significantly lower and quite stable demand. These findings are useful for designing network and QoE optimisation solutions, such as predictive pre-fetching, proxy caching and delay tolerant networking.
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| 4. |
- Nordell, Viktor, et al.
(författare)
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Concurrency and locality of content demand
- 2013
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Ingår i: 2013 International Conference on Smart Communications in Network Technologies, SaCoNeT 2013. - 9781479906949
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Konferensbidrag (refereegranskat)abstract
- Distribution of media data over the Internet is increasing in popularity and volume. This poses challenges not only for network operators but also for service providers when it comes to serving the demand in a cost-efficient way. In this paper, we approach this problem by investigating the potential of co-operative approaches where locality in space (users in the same network) and locality in time (concurrent downloads) are exploited such that as many requests as possible may be handled inside the access and metro networks. This approach may contribute not only to reducing transport costs (less traffic in core networks and at peering points) by but also improve the end user experience (by reduced round trip times and exclusion of some possible bottlenecks). To this end we develop a method to measure the possible gains from, firstly, optimal handling of concurrent downloads and, secondly, optimal utilization local availability. We apply the method to BitTorrent data from two metropolitan access networks and find that the bandwidth savings amount to between 10% and 20% when optimizing concurrent downloads and between 56% and 66% when exploiting local availability with a simulated network cache.
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| 5. |
- Arvidsson, Ake, et al.
(författare)
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Fast Transport for Edge Computing in 5G Networks
- 2018
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Ingår i: 2018 26TH INTERNATIONAL CONFERENCE ON SOFTWARE, TELECOMMUNICATIONS AND COMPUTER NETWORKS (SOFTCOM). - : IEEE. ; , s. 41-45
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Konferensbidrag (refereegranskat)abstract
- We consider TCP performance for cloud services in 5G cellular networks and show that edge clouds offer the highest throughput, but that further improvements still are possible. To this end we devise a concept where edge clouds connected directly to the radio access network can increase their transmission rates by relying on the built in re-transmissions (through quality of service features) and on the built in user fairness (through per-user buffers and scheduler policies). We use numerical examples from measurements in real networks to demonstrate that the concept is efficient and significantly improves the effective throughput beyond what placement alone can do, and we also outline possible further improvements.
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| 6. |
- Arvidsson, Åke, et al.
(författare)
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Load transients in pooled cellular core network nodes
- 2015
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Ingår i: Performance evaluation (Print). - : Elsevier BV. - 0166-5316 .- 1872-745X. ; 90, s. 18-35
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Tidskriftsartikel (refereegranskat)abstract
- The coverage areas of cellular networks are logically subdivided into service areas. Each service area has a local anchor node which “hides” the mobility inside the area and the entire network has a global anchor node which “hides” the mobility between areas. The concept of unique local anchor nodes per service area was invented to simplify routing but has been found to complicate expansion. The rapidly growing demand for cellular access has therefore prompted for alternative solutions with pools of local anchor nodes per service area. Such pools are now deployed by several operators all over the world. Users in pooled service areas are mapped to specific pool members according to a load distribution policy, but the mapping can change as a result of node failures or operator interventions. Such changes take a certain time to implement and cause additional load on the anchor nodes. We study these processes in detail and derive closed form expressions which allow operators to control the trade-off between rapid changes and acceptable loads. Finally we show that the key assumptions of our model are in agreement with measured data and demonstrate how the model can be applied to investigate the effects of different network settings (timers) under different user behaviour (traffic and mobility). Contrary to current solutions to this problem, which typically are slow and/or inaccurate, our results enable fast and accurate analysis of different scenarios thereby enabling operators to maximise utilisation of the existing investments and at the same time avoid potentially dangerous situations of overload.
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| 7. |
- Atxutegi, Eneko, et al.
(författare)
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TCP behaviour in LTE : impact of flow start-up and mobility
- 2016
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Ingår i: Wireless and Mobile Networking Conference (WMNC), 2016 9th IFIP. - : IEEE. ; , s. 73-80
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Konferensbidrag (refereegranskat)abstract
- Nowadays, more than two billion people uses the mobile internet, and it is expected to rise to almost 4 billion by 2020. Still, there is a gap in the understanding of how TCP and its many variants work over LTE. To this end, this paper evaluates the extent to which five common TCP variants, CUBIC, NewReno, Westwood+, Illinois, and CAIA Delay Gradient (CDG), are able to utilise available radio resources under hard conditions, such as during start-up and in mobile scenarios at different speeds. The paper suggests that CUBIC, due to its Hybrid Slow- Start mechanism, enters congestion avoidance prematurely, and thus experiences a prolonged start-up phase, and is unable to efficiently utilise radio resources during shorter transmission sessions. Still, CUBIC, Illinois and NewReno, i.e., the loss-based TCP implementations, offer better throughput, and are able to better utilise available resources during mobility than Westwood+ and CDG – the delay-based variants do.
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| 8. |
- Lakhan, Abdullah, et al.
(författare)
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Dynamic application partitioning and task-scheduling secure schemes for biosensor healthcare workload in mobile edge cloud
- 2021
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Ingår i: Electronics. - : MDPI AG. - 2079-9292. ; 10:22, s. 1-30
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Tidskriftsartikel (refereegranskat)abstract
- Currently, the use of biosensor-enabled mobile healthcare workflow applications in mobile edge-cloud-enabled systems is increasing progressively. These applications are heavyweight and divided between a thin client mobile device and a thick server edge cloud for execution. Application partitioning is a mechanism in which applications are divided based on resource and energy parameters. However, existing application-partitioning schemes widely ignore security aspects for healthcare applications. This study devises a dynamic application-partitioning workload task-scheduling-secure (DAPWTS) algorithm framework that consists of different schemes, such as min-cut algorithm, searching node, energy-enabled scheduling, failure scheduling, and security schemes. The goal is to minimize the energy consumption of nodes and divide the application between local nodes and edge nodes by applying the secure min-cut algorithm. Furthermore, the study devises the secure-min-cut algorithm, which aims to migrate data between nodesin a secure form during application partitioning in the system. After partitioning the applications, the node-search algorithm searches optimally to run applications under their deadlines. The energy and failure schemes maintain the energy consumption of the nodes and the failure of the system. Simulation results show that DAPWTS outperforms existing baseline approaches by 30% in terms of energy consumption, deadline, and failure of applications in the system.
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| 9. |
- Ali, Munwar, et al.
(författare)
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A Confidentiality-based data Classification-as-a-Service (C2aaS) for cloud security
- 2022
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Ingår i: Alexandria Engineering Journal. - : Alexandria University. - 1110-0168 .- 2090-2670. ; 64, s. 749-760
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Tidskriftsartikel (refereegranskat)abstract
- Rapid development and massive use of Information Technology (IT) have since produced a massive amount of electronic data. In tandem, the demand for data outsourcing and the associated data security is increasing exponentially. Small organizations are often finding it expensive to save and process their huge amount of data, and keep the data secure from unauthorized access. Cloud computing is a suitable and affordable platform to provide services on user demand. The cloud platform is preferable used by individuals, Small, and Medium Enterprises (SMEs) that cannot afford large-scale hardware, software, and security maintenance cost. Storage and processing of big data in the cloud are becoming the key appealing features to SMEs and individuals. However, the processing of big data in the cloud is facing two issues such as security of stored data and system overload due to the volume of the data. These storage methods are plain text storage and encrypted text storage. Both methods have their strengths and limitations. The fundamental issue in plain text storage is the high risk of data security breaches; whereas, in encrypted text storage, the encryption of complete file data may cause system overload. This paper propose a feasible solution to address these issues with a new service model called Confidentiality-based Classification-as-a-Service (C2aaS) that performs data processing by treating data dynamically according to the data security level in preparation for data storing in the cloud. In comparison to the conventional methods, our proposed service model is strongly showing good security for confidential data and is proficient in reducing cloud system overloading.
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| 10. |
- Arvidsson, A., et al.
(författare)
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Transport bottlenecks of edge computing in 5G networks
- 2019
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Ingår i: Journal of Communication Software and Systems. - : University of Split. - 1845-6421 .- 1846-6079. ; 15:1, s. 59-65
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Tidskriftsartikel (refereegranskat)abstract
- We consider bottlenecks of TCP throughput in scenarios with edge clouds and 5G cellular networks. By numerical examples from measurements in real networks, we show that edge clouds indeed improve throughput but that several, non-negligible bottlenecks remain. We therefore devise a concept where edge clouds connected directly to the radio access network can increase their transmission rates by relying on built in retransmissions (through quality of service features) and on the built in user fairness (through per-user buffers and scheduler policies). We then return to the numerical examples and show that our solution provides substantial gains and we conclude by identifying and discussing the remaining bottlenecks and the potential of an improved protocol.
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