Rodolfo da Silva Villaça

An Architecture for Mobility Support in a Next-Generation Internet

The current internetworking architecture presents some limitations to naturally support mobility, security and multi- homing. Among the limitations, the IP semantic overload seems to be a primary issue to be considered. In this paper we present a next generation internetworking architecture to overcome the IP semantic overload by introducing an identity layer located between the network and transport layers. This new layer provides a stable cryptographic identifier for end-hosts and seamlessly allows the deployment of new services, such as mobility, multi-homing and security. A prototype was implemented and evaluated considering some mobility scenarios, including intra-domain, inter-domain and simultaneous node mobility.

SDCCN: A Novel Software Defined Content-Centric Networking Approach

Content Centric Networking (CCN) represents an important change in the current operation of the Internet, prioritizing content over the communication between end nodes. Routers play an essential role in CCN, since they receive the requests for a given content and provide content caching for the most popular ones. They have their own forwarding strategies and caching policies for the most popular contents. Despite the number of works on this field, experimental evaluation of different forwarding algorithms and caching policies yet demands a huge effort in routers programming. In this paper we propose SDCCN, a SDN approach to CCN that provides programmable forwarding strategy and caching policies. SDCCN allows fast prototyping and experimentation in CCN. Proofs of concept were performed to demonstrate the programmability of the cache replacement algorithms and the Strategy Layer. Experimental results, obtained through implementation in the Mininet environment, are presented and evaluated.

Resilient Strategies to SDN: An Approach Focused on Actively Replicated Controllers

Software Defined Networking (SDN) are based on the separation of control and data planes. The SDN controller, although logically centralized, should be effectively distributed for high availability. Since the specification of OpenFlow 1.2, there are new features that allow the switches to communicate with multiple controllers that can play different roles -- master, slave, and equal. However, these roles alone are not sufficient to guarantee a resilient control plane and the actual implementation remains an open challenge for SDN designers. In this paper, we explore the OpenFlow roles for the design of resilient SDN architectures relying on multi-controllers. As a proof of concept, a strategy of active replication was implemented in the Ryu controller, using the OpenReplica service to ensure consistent state among the distributed controllers. The prototype was tested with commodity RouterBoards/MikroTik switches and evaluated for latency in failure recovery and switch migration for different workloads. We observe a set of trade-offs in real experiments with varyin workloads at both the data and control plane.

Analysis of Concept Similarity Methods Applied to an LSH Function

In literature, there are several methods to measure similarity between concepts in structures like simple ontologies, concept hierarchies, taxonomies, etc. These measures are used to search for similar concepts. In the Semantic Web, such structures are commonly used to classify data which opens the possibility of reasoning upon them and helps in conceptual searches. Besides that, the Locality Sensitive Hash (LSH) functions are used to store similar data close to each other in an index space. Each family of LSH functions is tied to a specific similarity function. In this paper we propose a method for combining the idea of conceptual similarity with LSH functions. This method permits the data classified as similar concepts be indexed close to each other respecting some metric. The main idea is to facilitate the conceptual searching for data semantically classified. This paper evaluates several methods of measuring the similarity between concepts in a simple ontology and discusses how they can be applied to an LSH function.

AR2C2: Actively replicated controllers for SDN resilient control plane

Software Defined Networking (SDN) is a promising architectural approach based on a programmatic separation of the control and data planes. For high availability purposes, logically centralized SDN controllers follow a distributed implementation. While controller role features in the OpenFlow protocol allow switches to communicate with multiple controllers, these mechanisms alone are not sufficient to guarantee a resilient control plane, leaving the actual implementation as open challenge for SDN designers. This paper explores OpenFlow roles for the design of resilient SDN control plane and proposes AR2C2 as an actively replicated multi-controller strategy. As proof of concept, AR2C2 is implemented based on the Ryu controller and relying on OpenReplica to ensure consistent state among the distributed controllers. Our prototype is experimentally evaluated using real commodity switches and Mininet emulated environment. Results of the measured times to recover from failures for different workloads shed some light on the practical trade-offs on replication overhead and latency as a step forward towards SDN resiliency.

HCube: Routing and similarity search in Data Centers

Abstract The current Big Data scenario is mainly characterized by the huge amount of data available on the Internet. Some deployed mechanisms for handling such raw data rely on Data Centres (DCs) based on massive storage, memory and processing capacity, in which solutions like BigTable, MapReduce and Dynamo process information in order to provide its retrieval. The HCube presents a DC alternative for data storage/retrieval based on the similarity search, in which similar content is concentrated on servers physically close within the HCube, simplifying the recovery of similar data. A similarity search is performed using a primitive get ( k , sim ) , in which k represents the reference content and sim a similarity threshold. The HCube network is organized in a three dimensional structure, in which the Gray Space Filling Curve (SFC) in conjunction with the Random Hyperplane Hashing (RHH) function and the XOR-based flat routing mechanism offer an efficient and powerful mechanism for the similarity search. In this context, this work presents the HCube networking solution, detailing the benefits of using the Gray SFC and the XOR-based flat routing mechanism for the similarity search.

An Architecture for Traffic Sign Management in Smart Cities

This paper introduces and evaluates a Traffic Sign Management Architecture (TSMA), which represents a paradigm shift for the deployment of traffic sign infrastructure in the context of Intelligent Transport Systems, Vehicular Networks and Smart Cities. The proposal addresses limitations of the current traffic control model by enabling remote updates of traffic signs and displaying them on the vehicular navigation system display to improve their legibility. TSMA is an architecture developed to provide V2I interaction using a commodity technology, Wi-Fi, through the beacon-stuffing technique. The initial design of TSMAs security mechanisms is also presented in this paper. Evaluations were performed on a developed prototype and simulation environments.

Organization of multimedia data for conceptual search based on ontologies

Nowadays, there is a large volume of semantically annotated multimedia data available in the Semantic Web. These data have originated from several different sources, generating new issues about their storage and retrieval. In this scenario, simple ontologies are commonly used to define knowledge domains and classify data into concepts, establishing relations between them. Such conceptual relationship may be measured by a similarity function which allows the search to be performed by similarity in an indexing system. The contribution of this paper is to propose how to organize multimedia data using this conceptual classification in LSH (Locality Sensitive Hashing) functions, facilitating the conceptual search in distributed systems like P2P networks.

SDMan: Towards a Software Defined Management Framework

Software Defined Infrastructure (SDI) has become a relevant topic for computing and communication industry. Despite this huge technological movement, Network and Systems Management has been disregarded as one of the main themes in this ecosystem, and Software Defined Infrastructure has been managed by semi-software-defined management solutions. In order to reduce this gap, this paper presents SDMan, a Software Defined Management framework. The SDMans proof of concept uses the OpenStack cloud platform and aims to demonstrate the feasibility of the proposed solution.

VirtPhy: Fully Programmable NFV Orchestration Architecture for Edge Data Centers

Emerging paradigms, such as edge computing, require the geographical distribution of small-scale data centers that will use network functions virtualization (NFV) to provide new services with stringent demands related to throughput, latency, cost, innovation, and efficient orchestration. To tackle these demands, this paper proposes VirtPhy, a fully programmable architecture for NFV orchestration in edge data centers, based on server-centric topologies, software-defined networking, software switches, distributed service chaining, and source routing. A proof-of-concept is implemented in a data center testbed using OpenStack cloud platform in a hypercube topology. The results show its orchestration mechanisms can efficiently provision NFV service requests by steering traffic through a sequence of virtualized network functions in a server-centric topology.