Christian Esteve Rothenberg

Software-Defined Networking: A Comprehensive Survey

The Internet has led to the creation of a digital society, where (almost) everything is connected and is accessible from anywhere. However, despite their widespread adoption, traditional IP networks are complex and very hard to manage. It is both difficult to configure the network according to predefined policies, and to reconfigure it to respond to faults, load, and changes. To make matters even more difficult, current networks are also vertically integrated: the control and data planes are bundled together. Software-defined networking (SDN) is an emerging paradigm that promises to change this state of affairs, by breaking vertical integration, separating the network’s control logic from the underlying routers and switches, promoting (logical) centralization of network control, and introducing the ability to program the network. The separation of concerns, introduced between the definition of network policies, their implementation in switching hardware, and the forwarding of traffic, is key to the desired flexibility: by breaking the network control problem into tractable pieces, SDN makes it easier to create and introduce new abstractions in networking, simplifying network management and facilitating network evolution. In this paper, we present a comprehensive survey on SDN. We start by introducing the motivation for SDN, explain its main concepts and how it differs from traditional networking, its roots, and the standardization activities regarding this novel paradigm. Next, we present the key building blocks of an SDN infrastructure using a bottom-up, layered approach. We provide an in-depth analysis of the hardware infrastructure, southbound and northbound application programming interfaces (APIs), network virtualization layers, network operating systems (SDN controllers), network programming languages, and network applications. We also look at cross-layer problems such as debugging and troubleshooting. In an effort to anticipate the future evolution of this new paradigm, we discuss the main ongoing research efforts and challenges of SDN. In particular, we address the design of switches and control platforms with a focus on aspects such as resiliency, scalability, performance, security, and dependabilityVas well as new opportunities for carrier transport networks and cloud providers. Last but not least, we analyze the position of SDN as a key enabler of a software-defined

LIPSIN: line speed publish/subscribe inter-networking

A large fraction of todays Internet applications are internally publish/subscribe in nature; the current architecture makes it cumbersome and inept to support them. In essence, supporting efficient publish/subscribe requires data-oriented naming, efficient multicast, and in-network caching. Deployment of native IP-based multicast has failed, and overlay-based multicast systems are inherently inefficient. We surmise that scalable and efficient publish/subscribe will require substantial architectural changes, such as moving from endpoint-oriented systems to information-centric architectures. In this paper, we propose a novel multicast forwarding fabric, suitable for large-scale topic-based publish/subscribe. Due to very simple forwarding decisions and small forwarding tables, the fabric may be more energy efficient than the currently used ones. To understand the limitations and potential, we provide efficiency and scalability analysis via simulations and early measurements from our two implementations. We show that the system scales up to metropolitan WAN sizes, and we discuss how to interconnect separate networks.

Theory and Practice of Bloom Filters for Distributed Systems

Many network solutions and overlay networks utilize probabilistic techniques to reduce information processing and networking costs. This survey article presents a number of frequently used and useful probabilistic techniques. Bloom filters and their variants are of prime importance, and they are heavily used in various distributed systems. This has been reflected in recent research and many new algorithms have been proposed for distributed systems that are either directly or indirectly based on Bloom filters. In this survey, we give an overview of the basic and advanced techniques, reviewing over 20 variants and discussing their application in distributed systems, in particular for caching, peer-to-peer systems, routing and forwarding, and measurement data summarization.

Revisiting routing control platforms with the eyes and muscles of software-defined networking

Prior work on centralized Routing Control Platform (RCP) has shown many benefits in flexible routing, enhanced security, and ISP connectivity management tasks. In this paper, we discuss RCPs in the context of OpenFlow/SDN, describing potential use cases and identifying deployment challenges and advantages. We propose a controller-centric hybrid networking model and present the design of the RouteFlow Control Platform (RFCP) along the prototype implementation of an AS-wide abstract BGP routing service.

Virtual routers as a service: the RouteFlow approach leveraging software-defined networks

The networking equipment market is being transformed by the need for greater openness and flexibility, not only for research purposes but also for in-house innovation by the equipment owners. In contrast to networking gear following the model of computer mainframes, where closed software runs on proprietary hardware, the software-defined networking approach effectively decouples the data from the control plane via an open API (i.e., OpenFlow protocol) that allows the (remote) control of packet forwarding engines. Motivated by this scenario, we propose RouteFlow, a commodity routing architecture that combines the line-rate performance of commercial hardware with the flexibility of open-source routing stacks (remotely) running on general purpose computers. The outcome is a novel point in the design space of commodity routing solutions with far-reaching implications towards virtual routers and IP networks as a service. This paper documents the progress achieved in the design and prototype implementation of our work and outlines our research agenda that calls for a community-driven approach.

Forwarding anomalies in Bloom filter-based multicast

Several recently proposed multicast protocols use in-packet Bloom filters to encode multicast trees. These mechanisms are in principle highly scalable because no per-flow state is required in the routers and because routing decisions can be made efficiently by simply checking for the presence of outbound links in the filter. Yet, the viability of previous approaches is limited by the possibility of forwarding anomalies caused by false positives inherent in Bloom filters. This paper explores such anomalies, namely (1) packets storms, (2) forwarding loops and (3) flow duplication. We propose stateless solutions that increase the robustness and the scalability of Bloom filter-based multicast protocols. In particular, we show that the parameters of the filter need to be varied to guarantee the stability of the packet forwarding, and we present a bit permutation technique that effectively prevents both accidental and maliciously created anomalies. We evaluate our solutions in the context of BloomCast, a source-specific inter-domain multicast protocol, using analytical methods and simulations.

A Review of Policy-Based Resource and Admission Control Functions in Evolving Access and Next Generation Networks

The IP Multimedia Subsystem (IMS) adopted in the core of Next Generation Networks (NGNs) promises to make network management easier by separating the control and the transport planes. Therefore, an interface between applications and the underlying transport network has been defined that offers a dynamic and efficient management of network resources based on a policy-based resource control engine. The resulting resource management framework enables the delivery of both the existing carrier grade existing and the next generation Quality of Service (QoS) sensitive services across operator-controlled networks using heterogeneous transport technologies. This review sheds some light into the policy control layer concept and the extended nomenclature introduced by current standardization works. The approaches of international standards development organizations, such as the Third Generation Partnership Project (3GPP), the International Telecommunication Union (ITU), the European Telecommunications Standards Institute (ETSI), the WiMAX Forum, and CableLabs are reviewed and compared with each other revealing the common architectural trend. Challenges and works in progress of NGN resource management towards Fixed and Mobile Convergence (FMC) are discussed as well.

Self-Routing Denial-of-Service Resistant Capabilities Using In-packet Bloom Filters

In this paper, we propose and analyze an in-packet Bloom-filter-based source-routing architecture resistant to Distributed Denial-of-Service attacks. The approach is based on forwarding identifiers that act simultaneously as path designators, i.e. define which path the packet should take, and as capabilities, i.e. effectively allowing the forwarding nodes along the path to enforce a security policy where only explicitly authorized packets are forwarded. The compact representation is based on a small Bloom filter whose candidate elements (i.e. link names) are dynamically computed at packet forwarding time using a loosely synchronized time-based shared secret and additional in-packet flow information (e.g., invariant packet contents). The capabilities are thus expirable and flow-dependent, but do not require any per-flow network state or memory look-ups, which have been traded-off for additional, though amenable, per-packet computation. Our preliminary security analysis suggests that the self-routing capabilities can be an effective building block towards DDoS-resistant network architectures.

The deletable Bloom filter: a new member of the Bloom family

We introduce the Deletable Bloom filter (DlBF) as a new spin on the popular data structure based on compactly encoding the information of where collisions happen when inserting elements. The DlBF design enables false-negative-free deletions at a fraction of the cost in memory consumption, which turns to be appealing for certain probabilistic filter applications.

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.