IEEE/ACM ToN

Distribuir contenido
TOC Alert for Publication# 90
Updated: hace 5 horas 47 mins

Table of Contents

Sáb, 09/30/2017 - 23:00
Presents the table of contents for this issue of the publication.
Categorías: research

IEEE/ACM Transactions on Networking publication information

Sáb, 09/30/2017 - 23:00
Provides a listing of current staff, committee members and society officers.
Categorías: research

Top- $k$ Queries for Categorized RFID Systems

Sáb, 09/30/2017 - 23:00
For categorized RFID systems, this paper studies the practically important problem of top-k queries, which is to find the top-k smallest and (or) the top-k largest categories, as well as the sizes of such categories. In this paper, we propose a Top-k Query (TKQ) protocol and two supplementary techniques called segmented perfect hashing (SPH) and switching to framed slotted aloha (STA) for optimizing TKQ. First, TKQ lets each tag choose a time slot to respond to the reader with a single-one geometric string using the ON-OFF Keying modulation. TKQ leverages the length of continuous leading 1 s in the combined signal to estimate the corresponding category size. TKQ can quickly eliminate most categories whose sizes are significantly different from the top-k boundary, and only needs to perform accurate estimation on a limited number of categories that may be within the top-k set. We conduct rigorous analysis to guarantee the predefined accuracy constraints on the query results. Second, to alleviate the low frame utilization of TKQ, we propose the SPH scheme, which improves its average frame utilization from 36.8% to nearly 100% by establishing a bijective mapping between tag categories and slots. To minimize the overall time cost, we optimize the key parameter that trades off between communication cost and computation cost. Third, we observed from the simulation traces that TKQ+SPH pays most execution time on querying a small number of remaining categories whose sizes are close to the top-k boundary, which sometimes even exceeds the time cost for precisely identifying these remaining tags. Motivated by this observation, we propose the STA scheme to dynamically determine when we should terminate TKQ+SPH and switch to use FSA to finish the rest of top-k query. Experimental results show that TKQ+SPH+STA not only achieves the required accuracy constraints, but also achieves several times faster speed than the existing protocols.
Categorías: research

Classification and Analysis of Communication Protection Policy Anomalies

Sáb, 09/30/2017 - 23:00
This paper presents a classification of the anomalies that can appear when designing or implementing communication protection policies. Together with the already known intra- and inter-policy anomaly types, we introduce a novel category, the inter-technology anomalies, related to security controls implementing different technologies, both within the same network node and among different network nodes. Through an empirical assessment, we prove the practical significance of detecting this new anomaly class. Furthermore, this paper introduces a formal model, based on first-order logic rules that analyses the network topology and the security controls at each node to identify the detected anomalies and suggest the strategies to resolve them. This formal model has manageable computational complexity and its implementation has shown excellent performance and good scalability.
Categorías: research

An Overlay Architecture for Throughput Optimal Multipath Routing

Sáb, 09/30/2017 - 23:00
Legacy networks are often designed to operate with simple single-path routing, like the shortest path, which is known to be throughput suboptimal. On the other hand, previously proposed throughput optimal policies (i.e., backpressure) require every device in the network to make dynamic routing decisions. In this paper, we study an overlay architecture for dynamic routing, such that only a subset of devices (overlay nodes) need to make the dynamic routing decisions. We determine the essential collection of nodes that must bifurcate traffic for achieving the maximum multi-commodity network throughput. We apply our optimal node placement algorithm to several graphs and the results show that a small fraction of overlay nodes is sufficient for achieving maximum throughput. Finally, we propose a threshold-based policy (BP-T) and a heuristic policy (OBP), which dynamically control traffic bifurcations at overlay nodes. Policy BP-T is proved to maximize throughput for the case when underlay paths do no overlap. In all studied simulation scenarios, OBP not only achieves full throughput but also reduces delay in comparison to the throughput optimal backpressure routing.
Categorías: research

Congestion Control for Web Real-Time Communication

Sáb, 09/30/2017 - 23:00
Applications requiring real-time communication (RTC) between Internet peers are ever increasing. RTC requires not only congestion control but also minimization of queuing delays to provide interactivity. It is known that the well-established transmission control protocol congestion control is not suitable for RTC due to its retransmissions and in-order delivery mechanisms, which induce significant latency. In this paper, we propose a novel congestion control algorithm for RTC, which is based on the main idea of estimating-using a Kalman Filter-the end-to-end one-way delay variation which is experienced by packets traveling from a sender to a destination. This estimate is compared with a dynamic threshold and drives the dynamics of a controller located at the receiver, which aims at maintaining queuing delays low, while a loss-based controller located at the sender acts when losses are detected. The proposed congestion control algorithm has been adopted by Google Chrome. Extensive experimental evaluations have shown that the algorithm contains queuing delays while providing intra and inter protocol fairness along with full link utilization.
Categorías: research

A Scalable Framework for Wireless Distributed Computing

Sáb, 09/30/2017 - 23:00
We consider a wireless distributed computing system, in which multiple mobile users, connected wirelessly through an access point, collaborate to perform a computation task. In particular, users communicate with each other via the access point to exchange their locally computed intermediate computation results, which is known as data shuffling. We propose a scalable framework for this system, in which the required communication bandwidth for data shuffling does not increase with the number of users in the network. The key idea is to utilize a particular repetitive pattern of placing the data set (thus a particular repetitive pattern of intermediate computations), in order to provide the coding opportunities at both the users and the access point, which reduce the required uplink communication bandwidth from users to the access point and the downlink communication bandwidth from access point to users by factors that grow linearly with the number of users. We also demonstrate that the proposed data set placement and coded shuffling schemes are optimal (i.e., achieve the minimum required shuffling load) for both a centralized setting and a decentralized setting, by developing tight information-theoretic lower bounds.
Categorías: research

Travi-Navi: Self-Deployable Indoor Navigation System

Sáb, 09/30/2017 - 23:00
We present Travi-Navi-a vision-guided navigation system that enables a self-motivated user to easily bootstrap and deploy indoor navigation services, without comprehensive indoor localization systems or even the availability of floor maps. Travi-Navi records high-quality images during the course of a guider's walk on the navigation paths, collects a rich set of sensor readings, and packs them into a navigation trace. The followers track the navigation trace, get prompt visual instructions and image tips, and receive alerts when they deviate from the correct paths. Travi-Navi also finds shortcuts whenever possible. In this paper, we describe the key techniques to solve several practical challenges, including robust tracking, shortcut identification, and high-quality image capture while walking. We implement Travi-Navi and conduct extensive experiments. The evaluation results show that Travi-Navi can track and navigate users with timely instructions, typically within a four-step offset, and detect deviation events within nine steps. We also characterize the power consumption of Travi-Navi on various mobile phones.
Categorías: research

Adaptive Joint Estimation Protocol for Arbitrary Pair of Tag Sets in a Distributed RFID System

Sáb, 09/30/2017 - 23:00
Radio frequency identification (RFID) technology has been widely used in Applications, such as inventory control, object tracking, and supply chain management. In this domain, an important research problem is called RFID cardinality estimation, which focuses on estimating the number of tags in a certain area covered by one or multiple readers. This paper extends the research in both temporal and spatial dimensions to provide much richer information about the dynamics of distributed RFID systems. Specifically, we focus on estimating the cardinalities of the intersection/differences/union of two arbitrary tag sets (called joint properties for short) that exist in different spatial or temporal domains. With many practical applications, there is, however, little prior work on this problem. We will propose a joint RFID estimation protocol that supports adaptive snapshot construction. Given the snapshots of any two tag sets, although their lengths may be very different depending on the sizes of tag sets they encode, we design a way to combine their information and more importantly, derive closed-form formulas to use the combined information and estimate the joint properties of the two tag sets, with an accuracy that can be arbitrarily set. By formal analysis, we also determine the optimal system parameters that minimize the execution time of taking snapshots, under the constraints of a given accuracy requirement. We have performed extensive simulations, and the results show that our protocol can reduce the execution time by multiple folds, as compared with the best alternative approach in literature.
Categorías: research

Milking the Cache Cow With Fairness in Mind

Sáb, 09/30/2017 - 23:00
Information-centric networking (ICN) is a popular research topic. At its heart is the concept of in-network caching. Various algorithms have been proposed for optimizing ICN caching, many of which rely on collaborative principles, i.e. multiple caches interacting to decide what to store. Past work has assumed altruistic nodes that will sacrifice their own performance for the global optimum. We argue that this assumption is insufficient and oversimplifies the reality. We address this problem by modeling the in-network caching problem as a Nash bargaining game. We develop optimal and heuristic caching solutions that consider both performance and fairness. We argue that only algorithms that are fair to all parties involved in caching will encourage engagement and cooperation. Through extensive simulations, we show our heuristic solution, FairCache, ensures that all collaborative caches achieve performance gains without undermining the performance of others.
Categorías: research

Quality-Aware Energy Optimization in Wireless Video Communication With Multipath TCP

Sáb, 09/30/2017 - 23:00
The advancements in wireless communication technologies prompt the bandwidth aggregation for mobile video delivery over heterogeneous access networks. Multipath TCP (MPTCP) is the transport protocol recommended by IETF for concurrent data transmission to multihomed terminals. However, it still remains challenging to deliver user-satisfied video services with the existing MPTCP schemes because of the contradiction between energy consumption and received video quality in mobile devices. To enable the energy-efficient and quality-guaranteed video streaming, this paper presents an energy-distortion-aware MPTCP (EDAM) solution. First, we develop an analytical framework to characterize the energy-distortion tradeoff for multipath video transmission over heterogeneous wireless networks. Second, we propose a video flow rate allocation algorithm to minimize the energy consumption while achieving target video quality based on utility maximization theory. The performance of the proposed EDAM is evaluated through both experiments in real wireless networks and extensive emulations in exata. Experimental results show that EDAM exhibits performance advantages over existing MPTCP schemes in energy conservation and video quality.
Categorías: research

Capability-Based Security Enforcement in Named Data Networking

Sáb, 09/30/2017 - 23:00
Named data networking (NDN) enhances traditional IP networking by supporting in-network content caching for better bandwidth usage and location-independent data accesses for multi-path forwarding. However, NDN also brings new security challenges. For example, an adversary can arbitrarily inject packets to NDN to poison content cache, or access content packets without any restrictions. We propose capability-based security enforcement architecture (CSEA), a capability-based security enforcement architecture that enables data authenticity in NDN in a distributed manner. CSEA leverages capabilities to specify the access rights of forwarded packets. It allows NDN routers to verify the authenticity of forwarded packets, and throttles flooding-based DoS attacks from unsolicited packets. We further develop a lightweight one-time signature scheme for CSEA to ensure the timeliness of packets and support efficient verification. We prototype CSEA on the open-source CCNx platform, and evaluate CSEA via testbed and Planetlab experiments. Our experimental results show that CSEA only incurs around 4% of additional delays in retrieving data packets.
Categorías: research

Energy Efficient Ethernet on MapReduce Clusters: Packet Coalescing To Improve 10GbE Links

Sáb, 09/30/2017 - 23:00
An important challenge of modern data centers is to reduce energy consumption, of which a substantial proportion is due to the network. Switches and NICs supporting the recent energy efficient Ethernet (EEE) standard are now available, but current practice is to disable EEE in production use, since its effect on real world application performance is poorly understood. This paper contributes to this discussion by analyzing the impact of EEE on MapReduce workloads, in terms of performance overheads and energy savings. MapReduce is the central programming model of Apache Hadoop, one of the most widely used application frameworks in modern data centers. We find that, while 1GbE links (edge links) achieve good energy savings using the standard EEE implementation, optimum energy savings in the 10 GbE links (aggregation and core links) are only possible, if these links employ packet coalescing. Packet coalescing must, however, be carefully configured in order to avoid excessive performance degradation. With our new analysis of how the static parameters of packet coalescing perform under different cluster loads, we were able to cover both idle and heavy load periods that can exist on this type of environment. Finally, we evaluate our recommendation for packet coalescing for 10 GbE links using the energy-delay metric. This paper is an extension of our previous work [1], which was published in the Proceedings of the 40th Annual IEEE Conference on Local Computer Networks (LCN 2015).
Categorías: research

Congestion Control for Background Data Transfers With Minimal Delay Impact

Sáb, 09/30/2017 - 23:00
Congestion control protocols for background data are commonly conceived and designed to emulate low priority traffic, which yields to transmission control protocol (TCP) flows. In the presence of even a few very long TCP flows, this behavior can cause bandwidth starvation, and hence, the accumulation of large numbers of background data flows for prolonged periods of time, which may ultimately have an adverse effect on the download delays of delay-sensitive TCP flows. In this paper, we look at the fundamental problem of designing congestion control protocols for background traffic with the minimum impact on short TCP flows while achieving a certain desired average throughput over time. The corresponding optimal policy under various assumptions on the available information is obtained analytically. We give tight bounds of the distance between TCP-based background transfer protocols and the optimal policy, and identify the range of system parameters for which more sophisticated congestion control makes a noticeable difference. Based on these results, we propose an access control algorithm for systems where control on aggregates of background flows can be exercised, as in file servers. Simulations of simple network topologies suggest that this type of access control performs better than protocols emulating low priority over a wide range of parameters.
Categorías: research

Optimizing Virtual Backup Allocation for Middleboxes

Sáb, 09/30/2017 - 23:00
In enterprise networks, network functions, such as address translation, firewall, and deep packet inspection, are often implemented in middleboxes. Those can suffer from temporary unavailability due to misconfiguration or software and hardware malfunction. Traditionally, middlebox survivability is achieved by an expensive active-standby deployment where each middlebox has a backup instance, which is activated in case of a failure. Network function virtualization (NFV) is a novel networking paradigm allowing flexible, scalable and inexpensive implementation of network services. In this paper, we suggest a novel approach for planning and deploying backup schemes for network functions that guarantee high levels of survivability with significant reduction in resource consumption. In the suggested backup scheme, we take advantage of the flexibility and resource-sharing abilities of the NFV paradigm in order to maintain only a few backup servers, where each can serve one of multiple functions when corresponding middleboxes are unavailable. We describe different goals that network designers can consider when determining which functions to implement in each of the backup servers. We rely on a graph theoretical model to find properties of efficient assignments and to develop algorithms that can find them. Extensive experiments show, for example, that under realistic function failure probabilities, and reasonable capacity limitations, one can obtain 99.9% survival probability with half the number of servers, compared with standard techniques.
Categorías: research

Power Efficiency and Delay Tradeoff of 10GBase-T Energy Efficient Ethernet Protocol

Sáb, 09/30/2017 - 23:00
In this paper, we study the power efficiency and delay performance of the burst mode transmission (BTR) strategy for the IEEE 802.3az energy efficient Ethernet (EEE) protocol. In the BTR strategy, the Ethernet interface goes to sleep once its transmission buffer becomes empty and wakes up as soon as the first arrival has waited for time r or the N-th frame arrives at the interface. Based on the number of arrivals during the vacation time, a new approach is proposed to analyze the M/G/1 queue with vacation times that are governed by the arrival process and the r and N parameters of BTR strategy. Our key idea is to establish the connection between the vacation time and the arrival process to account for their dependency. We first derive the distribution of the number of arrivals during a vacation time based on an event tree of the BTR strategy, from which, we obtain the mean vacation time and the power efficiency. Next, from the condition on the number of arrivals at the end of a vacation period, we derive a generalized P-K formula of the mean delay for EEE systems, and prove that the classical P-K formula of the vacation model is only a special case when the vacation time is independent of the arrival process. Our analysis demonstrates that the r policy and N policy of the BTR strategy are compensating each other. The r policy ensures the frame delay is bounded when the traffic load is light, while the N policy ensures the queue length at the end of vacation times is bounded when the traffic load is heavy. These results, in turn, provide the rules to select appropriate r and N. Our analytical results are confirmed by simulations.
Categorías: research

An Efficient Online Algorithm for Dynamic SDN Controller Assignment in Data Center Networks

Sáb, 09/30/2017 - 23:00
Software defined networking is increasingly prevalent in data center networks for it enables centralized network configuration and management. However, since switches are statically assigned to controllers and controllers are statically provisioned, traffic dynamics may cause long response time and incur high maintenance cost. To address these issues, we formulate the dynamic controller assignment problem (DCAP) as an online optimization to minimize the total cost caused by response time and maintenance on the cluster of controllers. By applying the randomized fixed horizon control framework, we decompose DCAP into a series of stable matching problems with transfers, guaranteeing a small loss in competitive ratio. Since the matching problem is NP-hard, we propose a hierarchical two-phase algorithm that integrates key concepts from both matching theory and coalitional games to solve it efficiently. Theoretical analysis proves that our algorithm converges to a near-optimal Nash stable solution within tens of iterations. Extensive simulations show that our online approach reduces total cost by about 46%, and achieves better load balancing among controllers compared with static assignment.
Categorías: research

Coding for Improved Throughput Performance in Network Switches

Sáb, 09/30/2017 - 23:00
Network switches and routers need to serve packet writes and reads at rates that challenge the most advanced memory technologies. As a result, scaling the switching rates is commonly done by parallelizing the packet I/Os using multiple memory units. For improved read rates, packets can be coded upon write, thus giving more flexibility at read time to achieve higher utilization of the memory units. This paper presents a detailed study of coded network switches, and in particular, how to design them to maximize the throughput advantages over standard uncoded switches. Toward that objective, the paper contributes a variety of algorithmic and analytical tools to improve and evaluate the throughput performance. The most interesting finding of this paper is that the placement of packets in the switch memory is the key to both high performance and algorithmic efficiency. One particular placement policy we call “design placement” is shown to enjoy the best combination of throughput performance and implementation feasibility.
Categorías: research

Routing in Accumulative Multi-Hop Networks

Sáb, 09/30/2017 - 23:00
This paper investigates the problem of finding optimal paths in single-source single-destination accumulative multi-hop networks. We consider a single source that communicates to a single destination assisted by several relays through multiple hops. At each hop, only one node transmits, while all the other nodes receive the transmitted signal, and store it after processing/decoding and mixing it with the signals received in previous hops. That is, we consider that terminals make use of advanced energy accumulation transmission/reception techniques, such as maximal ratio combining reception of repetition codes, or information accumulation with rateless codes. Accumulative techniques increase communication reliability, reduce energy consumption, and decrease latency. We investigate the properties that a routing metric must satisfy in these accumulative networks to guarantee that optimal paths can be computed with Dijkstra's algorithm. We model the problem of routing in accumulative multi-hop networks, as the problem of routing in a hypergraph. We show that optimality properties in a traditional multi-hop network (monotonicity and isotonicity) are no longer useful and derive a new set of sufficient conditions for optimality. We illustrate these results by studying the minimum energy routing problem in static accumulative multi-hop networks for different forwarding strategies at relays.
Categorías: research

Transient Community Detection and Its Application to Data Forwarding in Delay Tolerant Networks

Sáb, 09/30/2017 - 23:00
Community detection has received considerable attention because of its applications to many practical problems in mobile networks. However, when considering temporal information associated with a community (i.e., transient community), most existing community detection methods fail due to their aggregation of contact information into a single weighted or unweighted network. In this paper, we propose a contact-burst-based clustering method to detect transient communities by exploiting pairwise contact processes. In this method, we formulate each pairwise contact process as a regular appearance of contact bursts, during which most contacts between the pair of nodes happen. Based on this formulation, we detect transient communities by clustering the pairs of nodes with similar contact bursts. Since it is difficult to collect global contact information at individual nodes, we further propose a distributed method to detect transient communities. In addition to transient community detection, we also propose a new data forwarding strategy for delay tolerant networks, in which transient communities serve as the data forwarding unit. Evaluation results show that our strategy can achieve a much higher data delivery ratio than traditional community-based strategies with comparable network overhead.
Categorías: research