7989034
Internal popularity of streaming video and its implication on caching
As most proxy caches for streaming media cache only a part of the video, the most important issue for a caching algorithm is to determine which portion of the video should be cached. Due to different part of the video can have different popularity, the studying of the internal popularity characteristics of streaming videos is very important for the development of efficient cache mechanisms. In this paper, we showed that the internal popularity of the majority of the most popular videos obeys a k-transformed Zipf-like distribution through analyzing two 7-month long traces recorded at different streaming video servers of an entertainment video-on-demand provider. Based on this empirical internal popularity distribution model, we then proposed a new dynamical caching algorithm. The results of simulations proved that this algorithm can have better performance than algorithms based on other models and it has similar performance compare with fine-grained caching but requires significantly less state information.
14928068
Traffic engineering for MPLS-based virtual private networks
This paper considers the traffic engineering of MPLS-based Virtual Private Networks (VPNs) with multiple classes of service in an offline and centralised setting. We focus on two main issues. Firstly, we point out that the one label switched path (LSP) per ingress-egress pair constraint can be relaxed for the case of MPLS-based VPNs due to the ease in classifying flows on a per-VPN basis. This allows us to use LSP with finer granularity and thus better load balancing. Secondly, we point out that the single objective traffic engineering formulations proposed in literature address only one particular aspect of the traffic engineering problem. In this paper, we propose a multiobjective traffic engineering problem which takes resource usage, link utilisation and number of LSPs into account. The proposed optimisation problem is NP-complete and involves a large number of variables. We propose an heuristic to solve this problem.
8147679
Deploying long-lived and cost-effective hybrid sensor networks
In this paper, we consider the problem of network deployment in hybrid sensor networks, consisting of both resource-rich and resource-impoverished sensor devices. The resource-rich devices, called micro-servers, are more expensive but have significantly greater bandwidth and energy capabilities compared to the low-cost, lowpowered sensors. Such hybrid sensor networks have the potential to support the higher bandwidth communications of broadband sensor networking applications, as
7608405
Dynamic routing of restorable QoS connections in MPLS networks
In this paper we consider dynamic routing of restorable quality of service (QoS) connections in multi-protocol label switched (MPLS) networks under a single link failure model. To route a restorable QoS connection, two link disjoint label switched paths from the ingress to the egress node need to be computed such that both paths comply with the QoS constraints. When looking at QoS constraints like bandwidth guarantee and end-to-end delay bound, the current approach described in the literature converts the end-to-end delay bound into an effective bandwidth in a pre-processing step before computing two link disjoint bandwidth guaranteed paths. We argue that the current approach results in poor network performance and suggest a new approach that exploits the dependency between the end-to-end delay, chosen path and provisioned bandwidth. Thus, the two link disjoint paths are computed dynamically with their respective bandwidths so that they meet both the bandwidth guarantee and the end-to-end delay bound. In this paper, we present a new generic algorithm and two new linear programming formulations that implement the new approach. The two linear programming formulations are not intended to be used in a production environment due to their extensive running times, up to 2.5 minutes on average per request, but rather to benchmark approximation algorithms that in turn can be used in production. Furthermore our experiments show that the network performance improvement when exploiting the dependency between end-to-end delay, chosen path and provisioned bandwidth is substantial
41218825
Relaxed game chromatic number of graphs
This paper discusses a coloring game on graphs. Let k, d be non-negative integers and C a set of k colors. Two persons, Alice and Bob, alternately color the vertices of G with colors from C, with Alice having the first move. A color i is legal for an uncolored vertex x if by coloring x with color i, the subgraph of G induced by those vertices of color i has maximum degree at most d. Each move of Alice or Bob colors an uncolored vertex with a legal color. The game is over if either all vertices are colored, or no more vertices can be colored with a legal color. Alice's goal is to produce a legal coloring which colors all the vertices of G, and Bob's goal is to prevent this from happening. We shall prove that if G is a forest, then for k = 3, d ≥ 1, Alice has a winning strategy. If G is an outerplanar graph, then for k = 6 and d ≥ 1, Alice has a winning strategy.
1009354
Bistro: a scalable and secure data transfer service for digital government applications
14766680
QoS Driven Parallelization of Resources to Reduce File Download Delay
In this paper, we propose a novel approach for reducing the download time of large files over the Internet. Our approach, known as parallelized file transport protocol (P-FTP), proposes simultaneous downloads of disjoint file portions from multiple file servers. P-FTP server selects file servers for the requesting client on the basis of a variety of QoS parameters, such as available bandwidth and server utilization. The sensitivity analysis of our file server selection technique shows that it performs significantly better than random selection. During the file transfer, P-FTP client monitors the file transfer flows to detect slow servers and congested links and adjusts the file distributions accordingly. P-FTP is evaluated with simulations and real-world implementation. The results show at least 50 percent reduction in download time when compared to the traditional file-transfer approach. Moreover, we have also carried out a simulation-based study to investigate the issues related to large scale deployment of our approach on the Internet. Our results demonstrate that a large number of P-FTP users has no adverse effect on the performance perceived by non-P-FTP users. In addition, the file servers and network are not significantly affected by large scale deployment of P-FTP
14479349
Understanding and verifying distributed algorithms using stratified decomposition
Designers of autonomous distributed algorithms ( i.e., algorithms whose complete input is available before the start of execution) customarily refer to temporal ordering in describing the behavior of their algorithms-statements like “after A, task B is performed.” In the absence of an explicit termination detection for A built into the algorithm such a statement should be puzzling. However, the available proof methodologies do not seem to hinge on such statements. This paper provides firm theoretical ground for such as*Supported by NSF Presidential Young Investigators Award under grant DCR84-51396 and matching funds from IBM Faculty Development Award under grant D840622. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association for Computing Machinery. To copy otherwise, or to republish, requires a fee and/ or specific permission.