Juliano Araujo Wickboldt

Software-defined networking: management requirements and challenges

SDN is an emerging paradigm currently evidenced as a new driving force in the general area of computer networks. Many investigations have been carried out in the last few years about the benefits and drawbacks in adopting SDN. However, there are few discussions on how to manage networks based on this new paradigm. This article contributes to this discussion by identifying some of the main management requirements of SDN. Moreover, we describe current proposals and highlight major challenges that need to be addressed to allow wide adoption of the paradigm and related technology.

A framework for risk assessment based on analysis of historical information of workflow execution in IT systems

Services provided by modern organizations are usually designed, deployed, and supported by large-scale IT infrastructures. In order to obtain the best performance out of these services, it is essential that organizations enforce rational practices for the management of the resources that compose their infrastructures. A common point in most guides and libraries of best practices for IT management - such as ITIL or COBIT - is the explicit concern with the risks related to IT activities. Proactively dealing with adverse and favorable events that may arise during everyday operations might prevent, for example: delay on deployment of services, cost overrun in activities, predictable failures of handled resources, and, consequently, waste of money. Although important, risk management in practice usually lacks in automation and standardization in IT environments. Therefore, in this article, we introduce a framework to support the automation of some key steps of risk management. Our goal is to organize risk information related to IT activities providing support for decision making thus turning risk response planning simpler, faster, and more accurate. The proposed framework is targeted to workflow-based IT management systems. The fundamental approach is to learn from problems reported in the history of previously conducted workflows in order to estimate risks for future executions. We evaluated the applicability of the framework in two case studies both in IT related areas, namely: IT change management and IT project management. The results show how the framework is not only useful to speed up the risk assessment process, but also to assist the decision making of project managers and IT operators by organizing risk detailed information in a comprehensive way.

Interactive monitoring, visualization, and configuration of OpenFlow-based SDN

Software-Defined Networking (SDN) is an emerging paradigm that arguably facilitates network innovation and simplifies network management. However, in the context of SDN, management activities, such as monitoring, visualization, and configuration can be considerably different from traditional networks. An SDN controller, for example, can be customized by network administrators according to their needs. Such customizations might pose an impact on resource consumption and traffic forwarding performance, which is difficult to assess without an SDN-devoted management system. In this paper, we initially present an analysis of control traffic in SDN aiming to better understand the impact of the communication between the controller and forwarding devices. Afterwards, we propose an interactive approach to SDN management through monitoring, visualization, and configuration that includes the administrator in the management loop. To show the feasibility of our approach a prototype has been developed. The results obtained with this prototype show that our approach can help the administrator to better understand the impact of configuring SDN-related parameters on the overall network performance.

Improving IT Change Management Processes with Automated Risk Assessment

The rational management of IT infrastructures is a goal of modern organizations that aim to deliver high quality services to their customers in an affordable way. Since changes are imminent in such a dynamic environment, failures during this process may directly affect business continuity. Hence, risk assessment is a key process in IT change management. Despite its importance, risks are usually assessed by humans based on empirical knowledge, leading to inaccurate basis for decision making. In this paper, we present a solution for automating the risk assessment process, which combines historical data from previous changes and analyzes impact of changes over affected elements. A prototypical system was developed to evaluate the solution on an emulated IT infrastructure. The results achieved show how the automated solution is capable of raising the quality of changes, therefore reducing service disruption caused by changes.

Towards SLA Policy Refinement for QoS Management in Software-Defined Networking

Software-Defined Networking (SDN) is a dynamic, adaptable, controllable and flexible network architecture. It provides an extensible platform for delivery of network services, capable of responding quickly to service requirement changes. As a result, SDN has become a suitable scenario for the application of techniques and approaches for improved infrastructure management, such as Policy-Based Management (PBM). In PBM, using techniques such as refinement, a high-level policy-e.g., specified as a Service Level Agreement (SLA) - can be translated into a set of corresponding low-level rules, enforceable in various elements of a system. However, when using SLAs, their translation to low-level policies, e.g., for controller configuration, is not straightforward. If this translation is not done properly, the controller may not be able to meet the implicit requirements of the SLA, failing to satisfy the goals described in the high-level policy. This paper proposes a novel approach towards SLA policy refinement for Quality of Service (QoS) management (based on routing) in Software-Defined Networking. It consists of an initial manual process performed by an administrator, followed by an automatic policy refinement process executed by an OpenFlow controller. As a result, our approach is capable of identifying the requirements and resources that need to be configured in accordance with SLA refinement, and can successfully configure and execute reactive dynamic actions for supporting dynamic infrastructure reconfiguration.Software-Defined Networking (SDN) is a dynamic, adaptable, controllable and flexible network architecture. It provides an extensible platform for delivery of network services, capable of responding quickly to service requirement changes. As a result, SDN has become a suitable scenario for the application of techniques and approaches for improved infrastructure management, such as Policy-Based Management (PBM). In PBM, using techniques such as refinement, a high-level policy-e.g., specified as a Service Level Agreement (SLA) - can be translated into a set of corresponding low-level rules, enforceable in various elements of a system. However, when using SLAs, their translation to low-level policies, e.g., for controller configuration, is not straightforward. If this translation is not done properly, the controller may not be able to meet the implicit requirements of the SLA, failing to satisfy the goals described in the high-level policy. This paper proposes a novel approach towards SLA policy refinement for Quality of Service (QoS) management (based on routing) in Software-Defined Networking. It consists of an initial manual process performed by an administrator, followed by an automatic policy refinement process executed by an OpenFlow controller. As a result, our approach is capable of identifying the requirements and resources that need to be configured in accordance with SLA refinement, and can successfully configure and execute reactive dynamic actions for supporting dynamic infrastructure reconfiguration.

Resource management in IaaS cloud platforms made flexible through programmability

Abstract Infrastructure as a Service (IaaS) clouds are becoming a customary way to deploy modern Internet applications. Many cloud management platforms are available for one who wants to build a private or public IaaS cloud ( e.g. , OpenStack, Eucalyptus, OpenNebula). A common design aspect of current platforms regards their black-box-like controlling nature, where cloud administrators have few opportunities to influence how resources are actually managed ( e.g. , virtual machine placement or virtual link path selection). We envision that administrators could benefit from customizations in resource management strategies to achieve environment specific objectives or to enable application oriented resource allocation. In this article, we introduce a new concept of cloud management platform where resource management is made flexible by the addition of programmability to the core of the platform, with a simplified object-oriented API. We present a proof of concept prototype and an evaluation of three resource management programs on an emulated network using Linux virtualization containers and Open vSwitch running the OpenFlow protocol. Results show the feasibility of our approach and how optimization programs were able to achieve different objectives defined by the administrator.

On strategies for planning the assignment of human resources to IT change activities

Planning is a fundamental sub-process of the overarching Information Technology (IT) change management process, proposed by the Information Technology Infrastructure Library to help organizations to deploy and maintain IT services in an effective and efficient way. A major issue behind IT change planning and of special importance for the alignment of changes with business objectives/constraints - the adequate projection of which human resources to assign to change activities - has not been properly addressed in previous investigations. To fill this gap, in this paper we propose and analyze novel strategies for planning the assignment of human resources to change activities. These strategies explore different ways to prioritize humans to activities (i.e., from the most to the less efficient or proficient humans), and to rank/cluster the activities that should be analyzed first. The novel strategies have been experimentally evaluated through ChangeAdvisor, a prototypical implementation of a decision support system that helps IT administrators in the task of understanding the trade-offs between alternative change designs.

Capitalizing on SDN-based SCADA systems: An anti-eavesdropping case-study

Power grids are responsible for the transmission and distribution of electricity to end-users. These systems are undergoing a modernization process through the use of Information and Communication Technology (ICT), transforming the electric system into Smart Grids. In this context, Supervisory Control and Data Acquisition (SCADA) systems are responsible for the management and monitoring of substations and field devices. In this paper, we investigate the use of SDN as an approach to assist in the modernization of SCADA systems. We discuss its possible benefits, such as simplified management of power system resources. Moreover, SDN can facilitate the creation of new network applications that previously, with traditional networks, were more complex to be implemented. To illustrate the benefits of the use of SDN in SCADA, we designed a mechanism that aims to prevent a possible eavesdropper from fully capturing communication flows between SCADA components. The mechanism was implemented as an SDN-based application for SCADA systems that uses multipath routing, which relies on SDN features to frequently modify communication routes between SCADA devices. Further, we performed an experimental evaluation to verify the impact and performance of the mechanism in the SCADA network.

Policy authoring for software-defined networking management

Software-Defined Networking (SDN) permits centralizing part of the decision-logic in controller devices. Thus, controllers can have an overall view of the network, assisting network programmers to configure network-wide services. Despite this, the behavior of network devices and their configurations are often written for specific situations directly in the controller. As an alternative, techniques such as Policy-Based Network Management (PBNM) can be used by business-level operators to write Service Level Agreements (SLAs) in a user-friendly interface without the need to change the code implemented in the controllers. In this paper, we introduce a framework for Policy Authoring to (i) facilitate the specification of business-level goals and (ii) automate the translation of these goals into the configuration of system-level components in an SDN. We use information from the network infrastructure obtained through SDN features and logic reasoning for analyzing policy objectives. As a result, experiments demonstrate that the framework performs well even when increasing the number of expressions in an SLA or increasing the size of the repository.

CHANGEMINER: A solution for discovering IT change templates from past execution traces

The main goal of change management is to ensure that standardized methods and procedures are used for the efficient and prompt handling of changes in IT systems, in order to minimize change-related incidents and service-delivery disruption. To meet this goal, it is of paramount importance reusing the experience acquired from previous changes in the design of subsequent ones. Two distinct approaches may be usefully combined to this end. In a top-down approach, IT operators may manually design change templates based on the knowledge owned/acquired in the past. Considering a reverse, bottom-up perspective, these templates could be discovered from past execution traces gathered from IT provisioning tools. While the former has been satisfactorily explored in previous investigations, the latter - despite its undeniable potential to result in accurate templates in a reduced time scale - has not been subject of research, as far as the authors are aware of, by the service operations and management community. To fill in this gap, this paper proposes a solution, inspired on process mining techniques, to discover change templates from past changes. The solution is analyzed through a prototypical implementation of a change template miner subsystem called CHANGEMINER, and a set of experiments based on a real-life scenario.