Ricardo Luis dos Santos

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.

Policy-based dynamic service chaining in Network Functions Virtualization

Network Functions Virtualization (NFV) enables the rapid development, flexible management, and the dynamic placement of new, innovative Virtualized Network Functions (VNFs), such as load balancers, firewalls, and Intrusion Detection Systems (IDSes). Furthermore, NFV along with Software-Defined Networking (SDN) allows VNFs and physical middleboxes to be dynamically composed into service chaining graphs. Despite these benefits, service chaining graphs can be further improved through the use of techniques that have not been satisfactorily explored yet, such as Policy-Based Network Management (PBNM). In PBNM, policies can be written and triggered during runtime, thus supporting the dynamic (re)configuration of service graphs with minimal disruption. In this paper, we propose an approach to automatically design NFV service chaining graphs based on policies. These policies rule the forwarding of traffic and the construction of service chaining graphs. In our approach, service chaining graphs are enforced dynamically in the network during runtime. Finally, to assess its feasibility and generality, we create two different scenarios to demonstrate and discuss how our solution can be employed and its expected results.

A solution for identifying the root cause of problems in IT change management

The reuse of knowledge acquired by operators to diagnose failures in Information Technology (IT) infrastructures has potential to decrease the recurrence of failures and, consequently, reduce possible losses and maintenance costs. Nevertheless, existing solutions to support failure diagnosis lack of flexibility to adapt to a constantly changing IT environment. As a result, diagnostic is performed in an ad hoc and static fashion, which hampers the reuse of knowledge to solve similar failures affecting different elements of an IT infrastructure. To bridge this gap, in this paper we propose an extension of Common Information Model (CIM), supported by a conceptual solution for the identification of the root causes of problems, adaptable to changes in the target infrastructure and applicable to similar failures. Experiments carried out considering typical failures during the deployment of IT changes provide evidence about the efficacy of the proposed solution1.

VISION -- Interactive and Selective Visualization for Management of NFV-Enabled Networks

Network Functions Virtualization (NFV) enhances the flexibility of network service provisioning and reduces the time to services deployment. NFV and SDN promises transform the carrier networks, introducing innovation in the network core. NFV moves packet processing from dedicated hardware middleboxes to Virtualized Network Functions (VNFs), which run on virtual machines hosted on commercial off-the-shelf servers. However, in NFV-enabled networks, the amount of data managed grows in a fast way. Based on this, the network operator must understand and manipulate a lot of information to effectively manage the network. In this paper, we introduce the VISION, a platform to help the network operator to determine the cause of problems based on visualizations techniques. Our platform implements a set of interactive and selective visualizations to assist in the NFV management. Finally, we conducted three cases studies to provide evidences of the feasibility of our platform.

Computer-generated comprehensive risk assessment for IT project management

Information Technology (IT) products and services provided by modern organizations are designed in projects that often involve large amount of resources (e.g., humans, hardware, and software). It is essential that organizations enforce rational practices for project management, in order to successfully conclude projects and avoid waste of substantial resources. In this context, Risk Management is fundamental to guarantee the accomplishment of projects objectives by dealing with adverse and favorable events. Although important, risk assessment in IT projects is usually performed by stakeholders in interviews and brainstorms which may be a very time/resource-consuming task. Therefore, in this paper, we introduce a solution to automate the risk assessment process, based on the history of previously conducted projects. Furthermore, comprehensive and interactive risk reports are proposed in order to ease the analysis of automatically generated reports. The results show that our solution is not only useful to speed the risk assessment process, but also to assist the decision making of project managers by organizing risk information according to the project structure.

DReAM - a distributed result-aware monitor for Network Functions Virtualization

Network Functions Virtualization (NFV) is a key technology to reduce management costs as well as to improve scalability and elasticity of computer networks. Still, recent research efforts have been exposing additional management challenges. Concerning monitoring in particular, new types of entities and requirements are underexploited. To address these issues, we propose DReAM, a resource management architecture based on management by delegation and distributed monitoring, where each agent runs a diagnostic model to compute the network service state. In this paper, we describe DReAMs proposed architecture and its major components. We also discuss the feasibility of DReAM through experimental and analytical evaluations, where we observed application throughput, CPU utilization, communication overhead, scalability, and diagnosis complexity. We provide a trade-off analysis on the monitoring strategies in NFV scenarios. Our results indicate that a result-aware strategy is a better option when the monitored environment has more than 256 agents or when the diagnosis module induces at least 10% of CPU utilization.

App2net: A platform to transfer and configure applications on programmable virtual networks

In programmable virtual networks, simple tasks, like installing software, can be extremely complex. This complexity occurs mainly because the code transfer and initial functional settings in network execution environments are not automated. In addition, the same tasks have different requirements in each service lifecycle stage. In this sense, we propose the App2net platform for enabling the transfer and configuration of network applications in programmable virtual networks that use heterogeneous execution environments. We also propose a taxonomy for grouping code transfer techniques and, based on such techniques, we develop models for code transfer. A prototype has been implemented and tested on realistic network topologies commonly found on the Internet. Results allow us to identify which models improve code transfer consuming fewer resources, regarding service lifecycle stages and network topologies.

Leveraging IT project lifecycle data to predict support costs

There is an intuitive notion that the costs associated with project support actions, currently deemed too high and increasing, are directly related to the effort spent during their development and test phases. Despite the importance of systematically characterizing and understanding this relationship, little has been done in this realm mainly due to the lack of proper tooling for both sharing information between IT project phases and learning from past experiences. To tackle this issue, in this paper we propose a solution that, leveraging existing IT project lifecycle data, is able to predict support costs. The solution has been evaluated through a case study based on the ISBSG dataset, producing correct estimates for more than 80% of the assessed scenarios1.

IT Project Variables in the Balance: A Bayesian Approach to Prediction of Support Costs

In the context of Information Technology (IT) project management, it is commonly accepted that the costs associated with support actions are strongly influenced by the effort spent during their development and test phases. Despite the importance of systematically characterizing and understanding this relationship, little has been done in this realm mainly due to the lack of proper mechanisms for both sharing information between IT project phases and learning from past experiences. To tackle this issue, we present a Bayesian model to perform support cost predictions based on data from software development and test phases. In addition, we present a qualitative and quantitative analysis of the model, in order to demonstrate its effectiveness and efficiency, and also discuss its potentialities and limitations.

Affinity measurement for NFV-enabled networks: A criteria-based approach

Network Functions Virtualization (NFV) offers several benefits for Service Providers (SPs), such as mitigating equipment cost and increasing business agility. In NFV-enabled networks, inadequate placement of Virtualized Network Functions (VNFs) creates bottlenecks, impacting negatively on performance. Therefore, network operators must establish affinity and anti-affinity rules to avoid network and processing bottlenecks, and thus comply with Service Level Agreement (SLA) requirements of tenants. Affinity and anti-affinity rules in NFV must be broad and carefully elaborated to maintain service performance. Network operators must consider further than simply resource allocation when identifying affinity among VNFs. The criteria for VNFs affinity varies for different forwarding graphs. Geolocation, latency, packet loss, and bandwidth usage are some examples of criteria that can be considered as indicators of bottlenecks in high traffic networks. In this paper, we propose a solution to measure affinity between pairs of VNFs, based on a weighted set of affinity criteria considered relevant by a network operator. To evaluate the feasibility of our affinity model, we analyze three case studies over an experimental NFV scenario. We conclude that our affinity model can help network operators identify the cause of issues in NFV-enabled networks, as well as it may be used by NFV orchestrators to aid on VNFs migration and embedding.