Mateus Augusto Silva Santos

Mininet-WiFi: Emulating software-defined wireless networks

As the density of wireless networks continues to grow with more clients, more base stations, and more traffic, designing cost-effective wireless solutions with efficient resource usage and ease to manage is an increasing challenging task due to the overall system complexity. A number of vendors offer scalable and high-performance wireless networks but at a high cost and commonly as a single-vendor solution, limiting the ability to innovate after roll-out. Recent Software-Defined Networking (SDN) approaches propose new means for network virtualization and programmability advancing the way networks can be designed and operated, including user-defined features and customized behaviour even at run-time. However, means for rapid prototyping and experimental evaluation of SDN for wireless environments are not yet available. This paper introduces Mininet-WiFi as a tool to emulate wireless OpenFlow/SDN scenarios allowing high-fidelity experiments that replicate real networking environments. Mininet-WiFi augments the well-known Mininet emulator with virtual wireless stations and access points while keeping the original SDN capabilities and the lightweight virtualization software architecture. We elaborate on the potential applications of Mininet-Wifi and discuss the benefits and current limitations. Two use cases based on IEEE 802.11 demonstrate available functionality in our open source developments.

Software-defined-networking-enabled capacity sharing in user-centric networks

In this article, we discuss user-centric networks as a way of, if not completely solving, considerably mitigating the problem of sharing limited network capacity and resources efficiently and fairly. UCNs are self-organizing networks where the end user plays an active role in delivering networking functions such as providing Internet access to other users. We propose to leverage the recently proposed SDN paradigm to enable cooperation between wireless nodes and provide capacity sharing services in UCNs. Our SDNbased approach allows coverage of existing network infrastructure (e.g., WiFi or 3GPP) to be extended to other end users or ad hoc networks that would otherwise not be able to have access to network connectivity and services. Moreover, the proposed SDN-based architecture also takes into account current network load and conditions, and QoS requirements. Another important feature of our framework is that security is an integral part of the architecture and protocols. We discuss the requirements for enabling capacity sharing services in the context of UCNs (e.g., resource discovery, node admission control, cooperation incentives, QoS, security) and how SDN can aid in enabling such services. The article also describes the proposed SDN-enabled capacity sharing framework for UCNs.

MD2-NFV: The case for multi-domain distributed network functions virtualization

Motivated by the vision of Network Functions Virtualisation (NFV) spanning different administrative domains, this position paper makes the case for multi-domain, distributed NFV (MD2-NFV). To this end, we present MD2-NFV as a natural evolution of the NFV paradigm to deliver a distributed deployment of Virtualized Network Functions (VNFs) as a service. By means of three motivating use case scenarios, we discuss potential benefits and identify challenging features towards enabling advanced peering relationships between NFV domains.

Orchestration of RAN and Transport Networks for 5G: An SDN Approach

The fifth generation of mobile networks is planned to be commercially available in a few years. The scope of 5G goes beyond introducing new radio interfaces, and will include new services like low-latency industrial applications, as well as new deployment models such as cooperative cells and densification through small cells. An efficient realization of these new features greatly benefit from tight coordination among radio and transport network resources, something that is missing in current networks. In this article, we first present an overview of the benefits and technical requirements of resource coordination across radio and transport networks in the context of 5G. Then, we discuss how SDN principles can bring programmability to both the transport and radio domains, which in turn enables the design of a hierarchical, modular, and programmable control and orchestration plane across the domains. Finally, we introduce two use cases of SDN-based transport and RAN orchestration, and present an experimental implementation of them in a testbed in our lab, which confirms the feasibility and benefits of the proposed orchestration.

Dissecting the Largest National Ecosystem of Public Internet eXchange Points in Brazil

Many efforts are devoted to increase the understanding of the complex and evolving Internet ecosystem. Internet eXchange Points (IXP) are shared infrastructures where Autonomous Systems (AS) implement peering agreements for their traffic exchange. In recent years, IXPs have become an increasing research target since they represent an interesting microcosm of the Internet diversity and a strategic vantage point to deliver end-user services. In this paper, we analyze the largest set of public IXPs in a single country, namely the IX.br project in Brazil. Our in-depth analyses are based on BGP data from all looking glass servers and provide insights into the peering ecosystem per IXP and from a nation-wide perspective. We propose a novel peering affinity metric well-suited to measure the connectivity between different types of ASes. We found lower values of peering density in IX.br compared to more mature ecosystems, such as AMS-IX, DE-CIX, LINX, and MSK-IX. Our final contribution is sharing the 15 GB dataset along all supporting code.

Dynamically distributed network control for message dissemination in ITS

We propose D2-ITS, a flexible and extensible framework to dynamically distribute network control to enable message dissemination in Intelligent Transport Systems (ITS). By decoupling the control-from the data plane, D2-ITS leverages network programmability to address ITS scalability, delay intolerance and decentralization. It uses a distributed control plane based on a hierarchy of controllers that can dynamically adjust to environment- and network conditions in order to satisfy ITS application requirements. We demonstrate the benefits of D2-ITS through a proof-of-concept prototype using the ns-3 simulation platform. Results indicate lower message delivery latency with minimal additional overhead.

How directional mobility affects biodiversity in rock-paper-scissors models

This work deals with a system of three distinct species that changes in time under the presence of mobility, selection, and reproduction, as in the popular rock-paper-scissors game. The novelty of the current study is the modification of the mobility rule to the case of directional mobility, in which the species move following the direction associated to a larger (averaged) number density of selection targets in the surrounding neighborhood. Directional mobility can be used to simulate eyes that see or a nose that smells, and we show how it may contribute to reduce the probability of coexistence.

Anatomy of Public Internet eXchange Points Ecosystem in Brazil

For a long time many efforts were carried to increase the understanding of the complex Internet ecosystem. Internet eXchange Points have been targets since they represent a microcosm of Internet diversity. The contribution of this paper is the first empirical analysis of the IXP ecosystem in Brazil, compiling information that comprehend the characterization of members participating of these environments, including the build of AS-level connectivity graphs. By analysing the topologies we found the average adjacency of IXPs members (vertices degree), the isolated and accumulated depth of paths in advertised routes (AS-PATH), the density of peers to highlight the peering potential within IXPs, the accounting of traffic engineering policies related to AS-Prepend and k-clique communities. Another contribution is that our dataset with more than 2.5 GB is shared with the academic community.

Towards Semantic Network Models via Graph Databases for SDN Applications

At the core of any network control and management system is the representation and maintenance of network topology information. Software-Defined Networking (SDN) treats topology abstractions as one of the cornerstones towards rethinking network architectures and the way they are operated. Recently, motivated by the scalability and performance needs of cloud applications, Graph Databases are being adopted as appealing alternatives to traditional relational models when data is highly interconnected and extensible schemas are called for. In addition, the use of metadata to describe how data is interconnected by means of Web Semantic standards is increasingly gaining ground. At the crossroads of these trends, this paper presents an approach to augment SDN network state with a semantic model leveraging graph database technologies. In particular, our proposal imports the Network Mark up Language (NML) model into a scalable graph database (Neo4j). For validation purposes, we evaluate our proof of concept implementation against a representative set of SDN application primitives.