NVME RESOURCE GUARANTEE IN A NETWORK FABRIC

As the storage industry transitions towards the principal use of flash memory, a key element of that transition includes Non-Volatile Memory Express (NVMe) and, in particular, NVMe-TCP – i.e., NVMe over Transport Control Protocol (TCP). Techniques are presented herein that support a comprehensive, centralized scheme for provisioning end-to-end NVMe flows through existing data center switches, without requiring substantive changes to switch code, thus providing a flexible and highly visible resource-aware network provisioning solution for NVMe-TCP deployments

Evaluation of 802.11a for streaming data in ad-hoc networks

Abstract — Advances in communication and processing have made ad-hoc networks of wireless devices a reality. One application is home entertainment systems where multiple Home-to-Home (H2O) devices collaborate as peers to stream audio and video clips to a household. In this study, we investigate the feasibility of IEEE 802.11a protocol in combination with both TCP and UDP to realize a H2O device. Challenges include lossy connections, unfair allocation of bandwidth between multiple simultaneous transmissions, and the exposed node limitation [22], [19], [13], [4]. Our primary contribution is an empirical study of 802.11a to quantify these factors and their significance. Our multi-dimensional experimental design consists of the following axes: distance between participating devices, number of intermediate H2O devices used to route a stream from a producing H2O device to a consuming H2O device, and simultaneous number of active streams in the same radio range. Both operating system and application level routing were considered. Obtained results demonstrate the following lessons. First, with a multi-hop UDP transmission, in the absence of congestion control, transient bottlenecks result in a high loss rate. Hence, a transport protocol with congestion control is essential for streaming of continuous media within a H2O cloud. Second, 802.11a does not drop TCP connections in the presence of many competing transmissions (802.11b drops connections [22]). Third, we observed fairness when transmitting several hundred Megabytes (MB) of data, among multiple competing 1-hop TCP and UDP flows. Fourth, while there is unfair allocation of bandwidth with an exposed node, the observed bandwidths are sufficient to stream a high-quality video clip (with a 4 Mbps display bandwidth requirement). These results indicate streaming of data is feasible with an ad-hoc network of wireless devices employing the 802.11a protocol. I

Data replication and scheduling for content availability in vehicular networks

On-demand delivery of audio and video clips in a vehicular network is a growing area of interest. A given repository of such data items, each with an associated popularity, may be available to the passengers of the vehicles. The vehicles themselves are equipped with a 'TiVO' like device that has several gigabytes of storage and a wireless interface allowing short range communication at 10s to 100s of Megabits per second. The goal is to minimize the latency between request issuance and the time till a copy of the requested item is encountered. This latency is termed the availability latency. This thesis explores two generic tools to alleviate availability latency: (a) data replication (b) data delivery scheduling.\ud \ud With the replication study, we propose a general optimization formulation that seeks to minimize average availability latency subject to a storage constraint per vehicle. We explore the effects of a family of popularity-based replication schemes on availability latency. When the vehicles follow a 2D random walk based mobility model, via analysis and extensive simulations, we determine the optimal replication scheme that minimizes latency across a wide parameter space with major dimensions being data item size and client trip duration.\ud \ud Once an appropriate static replication scheme has allocated replicas, the vehicles themselves may be employed as data carriers to further improve availability latency. These data carriers are termed zebroids. However, a zebroid's local storage may be completely exhausted. Hence, to accommodate this new data item, it may need to evict an existing one. Various replacement policies such as LFU, LRU, random etc. are examined and their relative performance is studied. Via analysis and extensive simulations we study the behavior of zebroids as a function of large parameter space comprising data item repository size, storage per vehicle, number of vehicles, popularity distribution of the data items, different replacement schemes for zebroids etc.\ud \ud We validate the Markov model based observations with two independent validation phases employing (a) freeway traffic information on a city map (b) real world traces from a small bus network

Comparative analysis of push-pull query strategies for wireless sensor networks

Abstract. We present a comparative mathematical analysis of two important distinct approaches to hybrid push-pull querying in wireless sensor networks: structured hash-based data-centric storage (DCS) and the unstructured comb-needle (CN) rendezvous mechanism. Our analysis yields several interesting insights. For ALL-type queries pertaining to information about all events corresponding to a given attribute, we examine the conditions under which the two approaches outperform each other in terms of the average query and event rates. For the case of ANYtype queries where it is sufficient to obtain information from any one of the desired events for a given attribute, we propose and analyze a modified sequential comb-needle technique (SCN) to compare with DCS. We find that DCS generally performs better than CN/SCN for high query rates and low event rates, while CN/SCN perform better for high event rates. Surprisingly, for the cases of ALL-type aggregated queries and ANY-type queries, we find that there exist “magic number ” event rate thresholds, independent of network size or query probability, which dictate the choice of querying protocol. While our analysis is based on a single-sink square-grid deployment, we believe the insights can be generalized to random deployments.

Infection spread in wireless networks with random and adversarial node mobilities

We study the process of the spread of an infection among mobile nodes moving on a finite, grid based map. A random walk and a novel adversarial model are considered as two extreme cases of node mobility. With N nodes, we present analytical and simulation results for both mobility models for a square grid map with size √ G × √ G. A key finding is that with random mobility the total time to infect all nodes decreases with N while with an adversarial model we observe a reverse trend. Specifically, the random case results G log G log N N in a total infection time of Θ ( ) as opposed to the adversarial case where the total infection time is found to be Θ ( √ G log N). We also explore the possibility of emulating such an infection process as a mobile interaction game with wireless sensor motes, and the above results are complimented by traces obtained from an empirical study with humans as players in an outdoor field

MIGM: Mobile Interaction Games with Motes

Abstract—We propose the development of a broad range of exciting mobile interaction games using intermittently-connected wireless devices such as motes. As a concrete application, we describe the implementation of a random walk game, in which players each attempt to hold on to an otherwise itinerant token for as long as possible by running to evade other players in an open field. Besides obtaining the clear entertainment value, we argue that quantifying and analyzing key performance metrics recorded during the game can not only help people to evaluate player ability, but also provide some insights into adversarial behavior in both human and robotic settings. To this end, we present preliminary quantitative results and analysis for the random walk game obtained through real play evaluation. I. INTRODUCTION AND RELATED WORK The area of mobile interaction games with intermittently