Mikko Majanen

Energy-aware job scheduler for high-performance computing

In recent years energy-aware computing has become a major topic, not only in wireless and mobile devices but also in devices using wired technology. The ICT industry is consuming an increasing amount of energy and a large part of the consumption is generated by large-scale data centers. In High-Performance Computing (HPC) data centers, higher performance equals higher energy consumption. This has created incentives on exploring several alternatives to reduce the energy consumption of the system, such as energy-efficient hardware or the Dynamic Voltage and Frequency Scaling (DVFS) technique. This work presents an energy-aware scheduler that can be applied to a HPC data center without any changes in hardware. The scheduler is evaluated with a simulation model and a real-world HPC testbed. Our experiments indicate that the scheduler is able to reduce the energy consumption by 6–16% depending on the job workload. More importantly, there is no significant slowdown in the turnaround time or increase in the wait time of the job. The results hereby evidence that our approach can be beneficial for HPC data center operators without a large penalty on service level agreements.

An expert system for real-time traffic management in wireless local area networks

The paper explores delay-based congestion and flow control and the offloading of real-time traffic from wireless local area networks (WLANs) to mobile cellular networks (MCNs) in multihomed devices. The control system developed is based on an embedded hierarchical expert system. It adjusts transceivers’ traffic flow(s) for prevailing network conditions to achieve application-dependent delay and throughput limits. In wireless networks, delay and throughput depend on the packet size, packet transmission interval, and node connection density. Therefore, the controller on the destination node monitors average one-way delay and the change of one-way delay of the incoming traffic. On this basis, it adjusts the packet size and transmission interval of the source node by transmitting a control command to the source. If the prevailing level of traffic in the network exceeds its capacity despite of the control actions taken, devices prepare for developed asynchronous offloading of traffic to another access network. The control model was validated via simulation of Voice over Internet Protocol (VoIP) traffic in the OMNeT++ network simulator. The results demonstrate that the expert system developed is able to regulate packet sizes to match the prevailing application-dependent optimum and transfer traffic to another network if the network exceed its capacity no matter the control actions taken. Although this work is motivated mainly by issues of congestion and flow control of WLAN systems and the simulations and results were prepared for the IEEE 802.11b system, the approach and techniques are not limited to these systems, but they are applicable for other packet switched access networks (PSANs), too.

Cognitive Network Management Framework and Approach for Video Streaming Optimization in Heterogeneous Networks

The future Internet will be highly heterogeneous in supporting a multitude of access technologies and networks with overlapping coverages. Optimization of network operations like management of resources, mobility or Quality of Service in order to ensure smooth network operation and high user satisfaction will be very challenging in the future networks. Cognitive network management can provide a solution of managing such complex systems. This paper studies cognitive network management in the context of optimizing video streaming performance in heterogeneous multi-access networks. The paper proposes a network management framework that relies on cognitive decision techniques in the joint optimization of network and video service performance. The proposed solution is also implemented and validated in part in a testbed environment. The results attest the feasibility of the solution as well as the benefits of cognitive decision techniques over non-learning or non-adaptive approaches.

Analyzing transport and MAC layer in system-level performance simulation

The modern mobile embedded devices support complex distributed applications via heterogeneous multi-core platforms. For the successful deployment of these applications, the scalability and performance analysis must be performed at all the layers of OSI model. This helps to identify the potential bottlenecks at different layers to perform the necessary optimizations. To achieve this goal, a framework is needed which accurately models the functionalities at different layers. The technical contributions described in this article include the extensions of ABstract inStruction wOrkLoad & execUtion plaTform based performance simulation (ABSOLUT) for the performance and scalability analysis of Transport and Medium Access Control (MAC) layers in the system level performance simulation. The article elaborates the design accuracy of the modeled components and their application in the context of M3 (multi-device, multi-vendor, multi-domain), which is a tri-layered conceptual interoperability architecture for embedded devices. These extensions pave the way towards the full coverage of the OSI model in the system-level performance simulation of distributed embedded systems. The network simulators for example ns-2, OMNeT++ and OPNET though provide detailed models of transport and MAC protocols but do not provide any framework such that these models can be used by the application workload models to mimic the real world use-cases. Also these models do not model the execution workload of these protocols on a particular execution platform and hence cannot be used in the architectural exploration of distributed embedded systems.

Trigger Management and Mobile Node Cooperation

This chapter addresses one of the challenges in cooperative networking, namely, mobility support in a heterogeneous ambient network environment. We motivate the need for efficient mechanisms for handling the large amount of network and channel state information required in assisting fast handovers and network and service adaptation strategies. Managing a variety of network and protocol events and triggering information is a challenging task even in a homogeneous networking environment when different mobility schemes (node, network, session) and application adaptation are considered and, not unexpectedly, the heterogeneity of access networks increases further the amount of such information. We present triggering management mechanisms which efficiently handle triggering information at node and network level, dealing with a greater variety of events originating from any component of the node’s protocol stack as well as mobility management entities within the network. We then discuss the benefits of arranging mobile nodes into specific mobile routing groups, and how such approaches can benefit from the availability of the triggering management mechanisms in an ambient network environment.

Fuzzy Based Flow Management of Real-Time Traffic for Quality of Service in WLANs

Designing heterogeneous bandwidth limited communication systems that support a wide variety of applications, including file transfer, web browsing, interactive games, audio and video calls, and emerging real-time virtual world and social media applications is a challenging task because there is a shortage of resources to satisfy all traffic demands and diverse quality of service (QoS) requirements. For example, the current Internet architecture supports only best-effort service class which is not enough especially for delay sensitive real-time multimedia applications. Therefore, to improve QoS for specified traffic in the Internet, the end nodes (hosts) should make a bandwidth reservation through all the intermediate nodes, like access points and routers, by using some sort of resource reservation. For the QoS guarantee, the IETF has worked on the resource reservation protocol (RSVP) that can be used to hard resource reservation: an endpoint uses RSVP to request a simplex flow through the network with specified QoS bounds and the intermediate nodes, like routers, along the path either agree to honor the request or deny it. It is a transport layer protocol designed to reserve resources across a network. RSVP operates over an internet protocol versions 4 or 6 (IPv4 or IPv6) and provides receiver-initiated setup of resource reservations for multicast or unicast data flows. The drawback of the RSVP is that all the routers along the path must agree the resource reservation for QoS guarantee. However, no any QoS system can satisfy all users’ demands if the network traffic exceeds network capacity. Another disadvantage is that the reserved virtual links do not necessarily use the network capacity optimally. Therefore, we focus here to the cognitive flow management of delay sensitive constant bit rate real-time traffics, such as voice over internet protocols (VoIP), video calls, and interactive games, to improve QoS in Wireless Local Area Networks (WLANs). The Internet has two independent flow problems. Internet protocols need end-to-end flow control and a mechanism for intermediate nodes, like routers and access points, to control the amount of traffic known as the congestion prevention and control mechanism. Flow control is closely related to the point-to-point traffic between a sender and a receiver. It guarantees that a fast sender cannot continually send datagrams faster than a receiver can absorb them. Congestion is a condition of severe delay caused by an overload of datagrams at intermediate nodes. Usually congestion arises for two different reasons: a high-speed computer may be able to generate traffic faster than a network can transfer it or many computers send datagrams simultaneously through a single router, even though no single computer causes the problem. Hence, the congestion control can be considered more as a global issue whereas 18

An Evaluation of the Ambient Networks Gateway Selection Architecture

We study the performance of the gateway selection architecture (GSA), developed within the framework of the EU ambient networks integrated project, which provides support for gateway discovery, management, and selection for mobile nodes within dynamic routing groups. A routing group (RG) is a cluster of nodes in physical proximity, aware of the group membership, especially in the context of the Ambient Networks architecture, with a common goal of optimizing mobility management and routing functionality in the group. We present two examples on how GSA can be introduced using existing protocols, namely MIP and HIP. Our simulation studies show the benefits gained from group formation when compared to same functionalities implemented in every individual node, and compare the GSA optimized signaling strategy with other competitive approaches.

Micro-Segmenting 5G.

The forthcoming 5G mobile networks shall be heterogeneous in nature and embody a large number and variety of devices. Moreover, Internet of Things applications – like surveillance and maintenance – will use 5G extensively due to its high availability and quality of connectivity. However, the heterogeneous services, applications, users, devices, and the large amount of network traffic will bring challenges for the security of the mobile network. It will be important to provide isolated segments from the network for applications that require a high level of security. This paper presents the potential of micro-segmenting 5G networks. Microsegmentation is a concept that has been considered in data center networking to enforce the security of a data center by monitoring the flows inside the data center. In this paper we describe how the micro-segmentation concept could fit into the 5G security architecture and provide scenarios of how software mobile networks can facilitate securing IoT.

Security Awareness in Software-Defined Multi-Domain 5G Networks

Fifth generation (5G) technologies will boost the capacity and ease the management of mobile networks. Emerging virtualization and softwarization technologies enable more flexible customization of network services and facilitate cooperation between different actors. However, solutions are needed to enable users, operators, and service providers to gain an up-to-date awareness of the security and trustworthiness of 5G systems. We describe a novel framework and enablers for security monitoring, inferencing, and trust measuring. The framework leverages software-defined networking and big data technologies to customize monitoring for different applications. We present an approach for sharing security measurements across administrative domains. We describe scenarios where the correlation of multi-domain information improves the accuracy of security measures with respect to two threats: end-user location tracking and Internet of things (IoT) authentication storms. We explore the security characteristics of data flows in software networks dedicated to different applications with a mobile network testbed.