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Elasticity is a key component of modern cloud environments and monitoring is an essential part of this process. Monitoring demonstrates several challenges including gathering metrics from a variety of layers (infrastructure, platform, application), the need for fast processing of this data to enable efficient elasticity and the proper management of this data in order to facilitate analysis of current...
Network efficiency and proper utilization of its resources are essential requirements to operate wireless networks in an optimal fashion. Cognitive radio aims to fulfill these requirements by exploiting artificial intelligence techniques to create an entity called cognitive engine. Cognitive engine exploits awareness about the surrounding radio environment to optimize the use of radio resources and...
Motivated by the increasing trend of storing data for web applications in fast NoSQL systems, in this paper, we experiment with the leading NoSQL datastore — Cassandra — and a latest generation re-design of Cassandra — ScyllaDB — meant to deliver bleeding-edge performance on modern multicore machines. We evaluate the scalability claim of ScyllaDB, in terms of the number of clients, and provide diagnostic...
It is critical to provide sustained data throughput in edge computing, where several sensor devices generate information that needs to be fused and used for decision making in e.g., disaster incident scenes. To this end, we compare the effectiveness of two protocols, Hybrid Wireless Mesh Protocol (HWMP) and Greedy Perimeter Stateless Routing (GPSR), based upon their ability to stream data in a mesh...
LTE in Unlicensed band (LTE-U) has gained intensive attention recently due to its capability to offload mobile data to unlicensed bands. In order to use unlicensed band, LTE-U has to coexist with WiFi - another wireless technology that operates in unlicensed bands. This coexistence is riddled with several challenges as these technologies use different core networks, backhauls and deployment plans...
In current Data Center Networks (DCNs), Equal- Cost MultiPath (ECMP) is used as the de-facto routing protocol. However, ECMP does not differentiate between short and long flows, the two main categories of flows depending on their duration (lifetime). This issue causes hot-spots in the network, affecting negatively the Flow Completion Time (FCT) and the throughput, the two key performance metrics in...
Abstract-In cognitive radio networks, secondary users (SUs) face two conflicting objectives. Each SU seeks to minimize the sensing duration while maximizing the detection probability of primary users (PU) to avoid interfering with their transmissions. Both objectives have a substantial effect on energy efficiency. This paper investigates a noncooperative setting for selecting the sensing duration...
Many high-performance computing (HPC) sites extend their clusters to support Hadoop MapReduce for a variety of applications. However, HPC cluster differs from Hadoop cluster on the configurations of storage resources. In the Hadoop Distributed File System (HDFS), data resides on the compute nodes, while in the HPC cluster, data is stored on separate nodes dedicated to storage. Dedicated storage offloads...
This paper presents an LPV approach to dynamic modeling of a web-server hosted on a private cloud. The cloud hosting web-server is a variable capacity system with two control inputs, first is the number of virtual machines which is indicative of the capacity of the cloud and second is the admission control used for regulating the workload. As the workload and the hosting conditions change frequently,...
The increasing availability of 10G Ethernet network capabilities challenges existing transport layer protocols. As 10G connections gain momentum outside of backbone networks, the choice of appropriate TCP congestion control algorithms becomes even more relevant for networked applications running in environments such as data centers. Therefore, we provide an extensive overview of relevant TCP congestion...
The interconnection network has a large influence on total cost, application performance, energy consumption, and overall system efficiency of a supercomputer. Unfortunately, today's routing algorithms do not utilize this important resource most efficiently. We first demonstrate this by defining the dark fiber metric as a measure of unused resource in networks. To improve the utilization, we propose...
High throughput is of particular interest in data center and HPC networks. Although myriad network topologies have been proposed, a broad head-to-head comparison across topologies and across traffic patterns is absent, and the right way to compare worst-case throughput performance is a subtle problem. In this paper, we develop a framework to benchmark the throughput of network topologies, using a...
Polar codes are a new class of block codes with an explicit construction that provably achieve the capacity of various communications channels, even with the low-complexity successive-cancellation (SC) decoding algorithm. Yet, the more complex successive-cancellation list (SCL) decoding algorithm is gathering more attention lately as it significantly improves the error-correction performance of short-to...
The growing variety and consumption of the mobile services throughout the Long Term Evolution (LTE) mobile networks lead to various challenging issues in radio resource scheduling. One of the main challenges in LTE resource management is how to allocate the scare available bandwidth, especially in overload states of the network, to the services which have different characteristics and quality requirements...
In the past, several proposals to support fast handover in wireless mesh networks have been published. However, most handover extensions are only concerned with moving stations that are unaware of the used routing protocol and assume relatively stationary routing nodes. In this paper we propose an extension to the BATMAN routing protocol to support seamless handover of routing nodes in infrastructure...
The emerging software defined networking (SDN) provides a new paradigm of network management by separating control functionalities from underlying data forwarding hardware to an external controller. SDN provides high flexibility to control the whole network in a unified way. In this paper, we are motivated to study the performance issues of a software defined WiFi network testbed. This testbed consists...
Energy Efficiency is an important feature in poor-covered areas where not only the access to a cellular network is scarce but also energy sources are limited. In this paper, we consider a wireless mesh network to act as a local backhaul network to cover rural and remote villages. The shortage of energy in these settlements motivates to optimize the energy consumption of the wireless backhaul network...
Apache Storm has recently emerged as an attractive fault-tolerant open-source distributed data processing platform that has been chosen by many industry leaders to develop real-time applications for processing a huge amount of data in a scalable manner. A key aspect to achieve the best performance in this system lies on the design of an efficient scheduler for component execution, called topology,...
Irregularity is a recognized problem on many- and multi-core platforms but its effect remains to be studied. This paper focuses on multicore processors and assumes that packet traffic is processed by a large number of parallel jobs in realtime, while each job is implemented as a streaming algorithm. Analysis is performed using a real-life measurement dataset collected especially for this study while...
Software Defined Networking (SDN) is in the process of revolutionizing the way of managing networks by providing a new way to support current and future services. However, by relocating the control functionality in a remote entity, the measurements' accuracy of the resources' utilization becomes more difficult, which complicates the decision making. Although there are previous works focusing on the...
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