Efficient Content Delivery Research Articles

Network delay guarantee for differentiated services in content-centric networking

The newly adopted built-in caching mechanism guarantees efficient content delivery for content-centric networking (CCN) as compared to the existing IP-based networks such as the Internet. However, it is a challenge at the same time for CCN to meet QoS requirements due to content caching. In this paper, we investigate the problem of providing network delay guaranteed services in CCN. More specifically, we study the problem of meeting network delay requirements for differentiated services (content providers) in CCN while at the same time optimizing the overall content delivery performance.To support delay guarantee, we first present a simple and holistic network model which characterizes network delays of routing content to clients at different locations. By aligning network locations with content popularity, we ensure that each content provider has an optimized network delay of routing content to clients. We then derive analytical network delays for content providers by incorporating their content distribution models into the proposed holistic network model, and further formulate the delay guarantee task as a nonlinear integer programming (NIP) problem under the given network resources and traffic access patterns. We evaluate our mechanism and investigate the optimized network performance using different real/synthetic network topologies. With numerical studies, we analyze the process of competing for the network resources by different content providers, and investigate how various factors (e.g., content popularity, traffic volume, router storage capacity) affect this competition process. Our models and results presented in this paper provide guidance in designing resource provisioning and QoS mechanisms for CCN.

Boosting named data networking for data dissemination in urban VANET scenarios

Named Data Networking (NDN) is a data-centric networking architecture designed for the future Internet. Instead of establishing host-based end-to-end communications, NDN accomplishes the content retrieval and distribution through the delivery of named data. In this paper, we boost the NDN architecture to support efficient content delivery in urban Vehicular Ad hoc Networks (VANETs). First we propose a new geo-based NDN forwarding strategy to achieve efficient and reliable packet delivery in urban VANET scenarios. Then we investigate the caching redundancy problem with the default full-path caching scheme in VANETs, and present some heuristic strategies to reduce the unnecessary cached copies. Simulation results show that our forwarding strategy can greatly enhance NDN for data dissemination in urban VANETs, which achieves 27%∼75% higher request success ratio, and 40%∼80% lower delay compared with the original NDN strategy in scenarios with different vehicle densities. Besides, the caching strategies can reduce the cached copies by about 50% in dense scenarios with nearly no drops in the success ratio and negligible increase in delay.

Scalable and efficient file sharing in information-centric networking

Internet usage has been increasingly shifting toward massive content retrieval and distribution. To satisfy the demand, information-centric networking (ICN) approaches have emerged. These approaches have common features such as in-network caching and the decoupling of content and location to enable efficient content delivery. In this paper, we investigate the performance issue of file sharing in ICN. Compared to web and user generated content (UGC), file sharing entails relatively low request rates, but much larger content. These characteristics make it difficult for file sharing traffic to take advantage of in-network caching while competing with web and UGC traffic. For scalable and efficient file sharing, we design a peer-aware routing (PAR) protocol to utilize peers׳ storage in ICN. PAR uses a name-based shared tree without additional name resolution service. The shared tree is built at a network layer to connect peers for the same purpose, allowing a peer to discover the nearest peer holding the requested content in the tree. To evaluate the proposed PAR protocol, we conducted a large-scale simulation with a BitTorrent trace over the Internet-scale topology. We show that our protocol can substantially reduce inter-domain traffic, while keeping network overhead low.

Energy-aware cache management at the wireless network edge for information-centric operation

Information-centric networking (ICN) promises to overcome the networking challenges of the current Internet, e.g. the explosion of content consumption and the widening gap between traffic and capacity growth, by decoupling the content from the network locations. Simultaneously, the dominant mode of content access in Internet is materializing as IP-based broadband wireless networks with advanced user devices and ubiquitous mobile systems. Current caching-based solutions largely focus on improving the efficiency of content delivery while mostly overlooking energy efficiency aspects. However, the expanding networking infrastructure is expected to be more energy-efficient conforming to “green communications” concept while serving burgeoning traffic demands. Motivated by this concern, we study caching at the edge of an infrastructure-based mobile network supporting ICN with a focus on energy consumption of the considered system. We devise a greedy heuristic for cache management which incorporates energy reward, popularity, Time-To-Live (TTL) and delay (i.e. chunk loss due to delay sensitivity) factors. Our numerical analysis proves the energy savings achieved by the proposed greedy approach with low-complexity operation.

A novel networking architecture for mobile content delivery in urban transport systems

Today, the media content delivery in intermittent connected networks has become increasingly critical. This paper studies content exchange among mobile commuters in urban transport systems. Our work is inspired by two facts: (1) the commuters in urban transport systems tend to take regular routes to the same place every weekday and their paths exhibit a high degree of temporal and spatial regularities; (2) the rapid development of broadband wireless technologies such as IEEE 802.11n makes fast data transfer possible. We first propose a new disconnection-tolerant network infrastructure, which reinforces the connectivity of intermittent connected mobile commuters and uses store-and-forward routers to increase their encounter opportunity, and in turn achieves efficient media content delivery among them. Then a router-centric prediction method is designed to collect passengers' historical path information to determine the best delivery scheme. We evaluate the feasibility and the performance of the proposed infrastructure as well as the delivery scheme, using real data set from an urban transport system. The simulation results demonstrate the proposed system is highly practical in terms of the memory usage of routers and the maximum achievable data transfer rate.

Increasing the efficiency of real-time content delivery by improving the technology of priority assignment and processing of IP traffic

The method of dynamic prioritization of real-time multimedia flows is proposed. This method stabilizes the delay of packet processing when transmitting real-time flows in cases of network devices overload. As the result, the jitter of the flow can be significantly decreased. Moreover, decreasing the delay of packets processing allows to use the preserved time for more intelligent encryption algorithms that are usually very time-consuming. Based on the proposed prioritization method the algorithm of processing of high priority real-time flows that suffer from high delay has been developed in this paper. The algorithm is able to establish how long the specific packet has been transmitting through the network and determine the way to process it as fast as possible if the packets delay has exceeded a critical value. The proposed method and algorithm form a basis for ensuring quality of service in transport networks of long-distance class that require high level scalability and quality of service. This features are especially important when organizing networks of civil and military purposes including wireless broadband access networks. The proposed method becomes especially effective under the conditions of high incoming load on the communication core of the network since even small reduction of real time packets delay significantly increases quality of service. In case of special purpose networks, the developed algorithm allows to stabilize the delay and significantly decrease jitter which are a crucial factor when ensuring promptness of network reaction on the crisis situation.

GreenDelivery: proactive content caching and push with energy-harvesting-based small cells

The explosive growth of mobile multimedia traffic calls for scalable wireless access with high quality of service and low energy cost. Motivated by the emerging energy harvesting communications, and the trend of caching multimedia contents at the access edge and user terminals, we propose a paradigm-shift framework, namely GreenDelivery, enabling efficient content delivery with energy harvesting based small cells. To resolve the two-dimensional randomness of energy harvesting and content request arrivals, proactive caching and push are jointly optimized, with respect to the content popularity distribution and battery states. We thus develop a novel way of understanding the interplay between content and energy over time and space. Case studies are provided to show the substantial reduction of macro BS activities, and thus the related energy consumption from the power grid is reduced. Research issues of the proposed GreenDelivery framework are also discussed.

Efficient content delivery scheme for layered video streaming in large-scale networks

Providing efficient layered video streaming to heterogeneous users in varying network conditions requires dynamic bandwidth allocation, efficient data scheduling and incentives. In layered streaming, the video stream is composed of hierarchically encoded sub-stream layers namely the base layer and enhancements layers. We consider a scenario where receiver peers use a pull-based approach to adjust the video quality level to their terminal and network capacities by subscribing to a different number of layers. In this context, in order to take advantage of the available bandwidth in the network and to enhance end users Quality-of-Experience (QoE), we propose a novel approach that efficiently allocates sender peers׳ upload bandwidth to receiver peers. The upstream peer bandwidth is allocated depending on the quality level (requested layers) of the receiver peers, starting by allocating bandwidth for the lower layers first. In order to allocate bandwidth for a certain layer, an auction game is established to distribute the bandwidth among the receiver peers, where the sender peers “sell” their items (upload bandwidth) according to bids submitted by receiver peers. The main goal of this approach is to favor high priority peers while ensuring a minimum quality level to all peers. The proposed bandwidth allocation mechanism is paired with efficient scheduling mechanism for layered streaming. It aims to fully take advantage of the allocated bandwidth while respecting the layers dependency of the stream and the data blocks playback deadline. Extensive evaluations are conducted to compare our proposed algorithm with other bandwidth allocation strategies for layered video streaming. The obtained results show the effectiveness of our model in terms of video quality, useless chunks ratio and bandwidth utilization under different network/streaming conditions.

Service adaptive Network Architecture(SaNA)을 활용한 콘텐츠 전송 시스템

In recent years, various contents traffics are increasing according to the various internet connectable devices which have become contents provider. Because these contents traffics show different pattern from previous one, many researches for efficient contents delivery system are in progress. CCN(

Novel Architecture for a Mobile Content Delivery Network Based on Proxy Mobile IPv6

This study proposes an integrated technology based on Proxy Mobile IPv6, which is a network-based protocol with mobility support, and a mobile content delivery network (CDN) that provides efficient content delivery management. The proposed architecture offers several benefits, such as the conservation of network resources because of reduced total traffic between hops and a reduced hop count.

Cooperative Delivery Techniques to Support Video-on-Demand Service in IPTV Networks

In this paper, we study the use of peer-assisted server-based cooperative transmission strategies in IPTV networks for the delivery of on-demand services to end users. The proposed techniques aim to support the resource efficient delivery of on-demand content to end users in a timely manner. Within the proposed framework, a cooperative transmission strategy suggests that users who have access to the requested content cooperatively transmit to the targeted set of users. In doing so, we can minimize the servicing requirements at the server side and improve the scalability performance in the network. We conducted extensive simulations and showed that significant performance improvements can be achieved with the proposed delivery techniques to enable efficient access to an ever growing on-demand content. We also showed the robustness of the proposed techniques in regard to variations observed in network state.

IRep: indirect reciprocity reputation based efficient content delivery in BT-like systems

Delivering content efficiently through biased neighbor selection has attracted a lot of researchers' attention in recent years. Meanwhile, how to help peers understand each other is a crucial precondition of biased neighbor selection in distributed P2P context. Recent researches have showed that reciprocation based schemes provide a feasible way of categorizing peers. These schemes can perform in direct or indirect ways. For example, tit-for-tat is a typical example of direct ways, while reputation-based schemes are the representative examples of indirect ways. Although tit-for-tat has been proved to be successful from practical deployment and academic studies, it still suffers from free-riding, malicious peers and other problems. On the other hand, reputation-based schemes pay little attention to malicious peers. However, in this paper we propose an approach to promote the whole system performance as well as cope with malicious peers. Firstly, by building a simple mathematical model for the content delivery process in BT-like system, we find that the delivery order is critical to system performance, after that we present the best selection policy from system and single peer's perspective respectively. Secondly, according to analysis results, we bring forward indirect reciprocate Reputation (iRep), detail the design issues and sketch security and overhead introduced by iRep. Finally, several simulation experiments are conducted to evaluate the performance of iRep through comparison with tit-for-tat and Eigentrust. The comparison results validate that iRep can efficiently promote system performance with limited overheads.

On the potential of recommendation technologies for efficient content delivery networks

During the last decade, we have witnessed a substantial change in content delivery networks (CDNs) and user access paradigms. If previously, users consumed content from a central server through their personal computers, nowadays they can reach a wide variety of repositories from virtually everywhere using mobile devices. This results in a considerable time-, location-, and event-based volatility of content popularity. In such a context, it is imperative for CDNs to put in place adaptive content management strategies, thus, improving the quality of services provided to users and decreasing the costs. In this paper, we introduce predictive content distribution strategies inspired by methods developed in the Recommender Systems area. Specifically, we outline different content placement strategies based on the observed user consumption patterns, and advocate their applicability in the state of the art CDNs.

Performance analysis of in-network caching for content-centric networking

With the explosion of multimedia content, Internet bandwidth is wasted by repeated downloads of popular content. Recently, Content-Centric Networking (CCN), or the so-called Information-Centric Networking (ICN), has been proposed for efficient content delivery. In this paper, we investigate the performance of in-network caching for Named Data Networking (NDN), which is a promising CCN proposal. First, we examine the inefficiency of LRU (Least Recently Used) which is a basic cache replacement policy in NDN. Then we formulate the optimal content assignment for two in-network caching policies. One is Single-Path Caching, which allows a request to be served from routers only along the path between a requester and a content source. The other is Network-Wide Caching, which enables a request to be served from any router holding the requested content in a network. For both policies, we use a Mixed Integer Program to optimize the content assignment models by considering the link cost, cache size, and content popularity. We also consider the impact of link capacity and routing issues on the optimal content assignment. Our evaluation and analysis present the performance bounds of in-network caching on NDN in terms of the practical constraints, such as the link cost, link capacity, and cache size.

Scalable Media Coding Enabling Content-Aware Networking

Increasingly popular multimedia services are expected to play a dominant role in the future of the Internet. In this context, it is essential that content-aware networking (CAN) architectures explicitly address the efficient delivery and processing of multimedia content. This article proposes the adoption of a content-aware approach into the network infrastructure, thus making it capable of identifying, processing, and manipulating media streams and objects in real time to maximize quality of service (QoS) and experience (QoE). Our proposal is built on the exploitation of scalable media coding technologies within such a content-aware networking environment. This discussion is based on four representative use cases for media delivery (unicast, multicast, peer-to-peer, and adaptive HTTP streaming) and reviews CAN challenges, specifically flow processing, caching/buffering, and QoS/QoE management.

Efficient Lookup Scheme for Non-aggregatable Name Prefixes and Its Evaluation

Content-Centric Networking (CCN) employs a hierarchical but location independent content naming scheme. While such a location independent naming brings various benefits including efficient content delivery, mobility, and multihoming, location independent name prefixes are hard to aggregate. This poses a serious scaling issue on the efficiency of looking up content names in a huge Forwarding Information Base (FIB) by longest prefix matching, which requires seeking the longest matching prefix through all candidate prefix lengths. We propose a new scheme for efficiently looking up non-aggregatable name prefixes in a large FIB. The proposed scheme is based on the observation that the bottleneck of FIB lookup is the random accesses to the high-latency off-chip DRAM for prefix seeking and this can be reduced by exploiting the information on the longest matching prefix length in the previous hop. Our evaluation results show that the proposed scheme significantly improves FIB lookup latency with a reasonable traffic parameters observed in today's Internet.

Popularity Aware Limited Caching for Reliable On Demand P2P Video Streaming

In nowadays network group, the Peer-To-Peer (P2P) network is exploring as a good environment for resource sharing over the Internet. Compared with traditional file sharing workloads, continuous streaming of multimedia content provokes a significant amount of today’s internet traffic. Streaming media has various real-time constraints such as insufficient memory, high bandwidth utilization for largescale media objects, and lack of cooperation between proxies and their clients. Under these circumstances, it is a challenging task to achieve efficient content delivery under the increased availability of continuous-media streaming. In this paper, PALC (Popularity Aware Limited caching) is proposed to achieve efficient, reliable and scalable P2P-VoD system. It is an attractive approach to minimize the network traffic incurred in video streaming through cooperative caching. In this approach, P2P network is constructed in the form of a two-tier architecture, where the upper tier is composed of proxy overlay with high connectivity super peers. It serves as a structured DHT node to maintenance the detached hash table for prominent information retrieval. On the contrary, in lower tier, less connectivity peers are loosely coupled to the corresponding super peers in the form of unstructured network. We proposed an efficient hybrid proxy caching system in order to reduce the network/ server load while improving the end user perceived video quality. It also proposes an efficient Popularity Aware Limited Caching (PALC) algorithm that cooperatively utilizes the memory space of the proxy servers and clients to achieve efficient and cost effective P2P video streaming. The effectiveness of the proposed approach is evaluated under various network and end system configurations. The experimental results demonstrate that the proposed approach incurs minimum Internet traffic and low cost of transmission as compared to the proxy-based caching approach with limited storage space.

Multi-criteria decision algorithms for efficient content delivery in content networks

Today’s Internet is prominently used for content distribution. Various platforms such as content delivery networks (CDNs) have become an integral part of the digital content ecosystem. Most recently, the information-centric networking (ICN) paradigm proposes the adoption of native content naming for secure and efficient content delivery. This further enhances the flexibility of content access where a content request can be served by any source within the Internet. In this paper, we propose and evaluate a multi-criteria decision algorithm for efficient content delivery applicable for content networks in general (among others, CDN and ICN). Our algorithm computes the best available source and path for serving content requests taking into account information about content transfer requirements, location of the consumer, location of available content servers, content server load and content delivery paths between content servers and consumer. The proposed algorithm exploits two closely related processes. The first level discovers multiple content delivery paths and gathers their respective transfer characteristics. This discovery process is based on long-term network measurements and performed offline. The second process is invoked for each content request to find the best combined content server and delivery path. The cooperation between both levels allows our algorithm to increase the number of satisfied content requests thanks to efficient utilisation of network and server resources. The proposed decision algorithm was evaluated by simulation using Internet scale network model. The results confirm the effectiveness gain of content network architectures that introduce network awareness. Moreover, the simulation process allows for a comparison between different routing algorithms and, especially, between single and multipath routing algorithms.

CRAW: Combination of Re-Keying and Authentication in Wireless Networks for Secure Multicast Increasing Efficiency of Member Join/Leave and Movement

Recently, the number of requests for multicast services through the wireless networks has been increased. However, for successful deployment, security and efficiency of content delivery must be provided at first. This paper presents a new approach for secure multicast in wireless networks. This approach, CRAW (Combination of Re-keying and Authentication in Wireless networks) combines member authentication procedure with group key management protocol to provide an efficient group re-keying process. One-time password is proposed for member authentication and CKC (Code for Key Calculation) is suggested for group key management in wireless networks. In fact, the combination of authentication with group key management in wireless networks results in a simple and secure mechanism both for authentication and group key management while mobile members join/leave a group or move inter-area. Simulation results show that CRAW reduces re-keying overhead at join from O(log2 n+1) to O(1) while security requirements are saved. Also, CRAW introduces storing a main list to manage mobile members' location while they move intra-group inter-area.

Altering the Athletic Training Curriculum: A Unique Perspective on Learning Over Time

Context: The cohort athletic training curriculum features a competency-based approach that allows the student to matriculate through the program in a systematic fashion. This method is desired as it allows for efficient delivery and mastery of the educational content and associated clinical skills. The result may be an inflexible curriculum that can be unforgiving when unforeseen circumstances arise. Objective: To introduce a unique curricular design to the undergraduate athletic training setting that is more flexible than the traditional curricular model. Background: Athletic training education has expanded and proliferated greatly since 1998. The high rate of growth resulted in programs that are similar in design. The curricular structure is based on competency-based categories whose subjects rely on each other so strongly that there is little flexibility. This rigidity can create matriculation issues for students who are unable to proceed through the program at the required pace. Synthesis: Review of the current curricular model and accompanying literature indicates a desire for a new curricular model to provide flexibility within the athletic training curriculum. Results: The Adaptive Athletic Training model provides a flexible alternative to the cohort athletic training curriculum. This design uses a holistic and problem-based approach that is more closely associated with the entry-level workplace. Limitations include its ability to conform directly to the Commission onbetter Accreditation of Athletic Training Education competency matrix and the increased academic resources needed for implementation. Recommendations: Professional athletic training education programs should examine whether their current curricular model benefits their student population in the greatest extent. If room for improvement is identified, then alternative curricular models should be explored. Conclusions: The Adaptive Athletic Training model provides a flexible curricular option when examining alternative professional athletic training education program curriculums.