Global state, local decisions: Decentralized NFV for ISPs via enhanced SDN

The network functions virtualization paradigm is rapidly gaining interest among Internet service providers. However, the transition to this paradigm on ISP networks comes with a unique set of challenges: legacy equipment already in place, heterogeneous traffic from multiple clients, and very large scalability requirements. In this article we thoroughly analyze such challenges and discuss NFV design guidelines that address them efficiently. Particularly, we show that a decentralization of NFV control while maintaining global state improves scalability, offers better per-flow decisions and simplifies the implementation of virtual network functions. Building on top of such principles, we propose a partially decentralized NFV architecture enabled via an enhanced software-defined networking infrastructure. We also perform a qualitative analysis of the architecture to identify advantages and challenges. Finally, we determine the bottleneck component, based on the qualitative analysis, which we implement and benchmark in order to assess the feasibility of the architecture.Peer ReviewedPostprint (author's final draft

Explicit context matching in content-based publish/subscribe systems

Although context could be exploited to improve performance, elasticity and adaptation in most distributed systems that adopt the publish/subscribe (P/S) communication model, only a few researchers have focused on the area of context-aware matching in P/S systems and have explored its implications in domains with highly dynamic context like wireless sensor networks (WSNs) and IoT-enabled applications. Most adopted P/S models are context agnostic or do not differentiate context from the other application data. In this article, we present a novel context-aware P/S model. SilboPS manages context explicitly, focusing on the minimization of network overhead in domains with recurrent context changes related, for example, to mobile ad hoc networks (MANETs). Our approach represents a solution that helps to efficiently share and use sensor data coming from ubiquitous WSNs across a plethora of applications intent on using these data to build context awareness. Specifically, we empirically demonstrate that decoupling a subscription from the changing context in which it is produced and leveraging contextual scoping in the filtering process notably reduces (un)subscription cost per node, while improving the global performance/throughput of the network of brokers without fltering the cost of SIENA-like topology changes

ZeroComm: Decentralized, Secure and Trustful Group Communication

In the context of computer networks, decentralization is a network architecture that distributes both workload and control of a system among a set of coequal participants. Applications based on such networks enhance trust involved in communication by eliminating the external author- ities with self-interests, including governments and tech companies. The decentralized model delegates the ownership of data to individual users and thus mitigates undesirable behaviours such as harvesting personal information by external organizations. Consequently, decentral- ization has been adopted as the key feature in the next generation of the Internet model which is known as Web 3.0. DIDComm is a set of abstract protocols which enables secure messaging with decentralization and thus serves for the realization of Web 3.0 networks. It standardizes and transforms existing network applications to enforce secure, trustful and decentralized com- munication. Prior work on DIDComm has only been restricted to pair-wise communication and hence it necessitates a feasible strategy for adapting the Web 3.0 concepts in group-oriented networks. Inspired by the demand for a group communication model in Web 3.0, this study presents Zero- Comm which preserves decentralization, security and trust throughout the fundamental opera- tions of a group such as messaging and membership management. ZeroComm is built atop the publisher-subscriber pattern which serves as a messaging architecture for enabling communi- cation among multiple members based on the subjects of their interests. This is realized in our implementation through ZeroMQ, a low-level network library that facilitates the construction of advanced and distributed messaging patterns. The proposed solution leverages DIDComm protocols to deliver safe communication among group members at the expense of performance and efficiency. ZeroComm offers two different modes of group communication based on the organization of relationships among members with a compromise between performance and security. Our quantitative analysis shows that the proposed model performs efficiently for the messaging operation whereas joining a group is a relatively exhaustive procedure due to the es- tablishment of secure and decentralized relationships among members. ZeroComm primarily serves as a low-level messaging framework but can be extended with advanced features such as message ordering, crash recovery of members and secure routing of messages

Taking Arduino to the Internet of things: the ASIP programming model

Micro-controllers such as Arduino are widely used by all kinds of makers worldwide. Popularity has been driven by Arduino’s simplicity of use and the large number of sensors and libraries available to extend the basic capabilities of these controllers. The last decade has witnessed a surge of software engineering solutions for “the Internet of Things”, but in several cases these solutions require computational resources that are more advanced than simple, resource-limited micro-controllers. Surprisingly, in spite of being the basic ingredients of complex hardware–software systems, there does not seem to be a simple and flexible way to (1) extend the basic capabilities of micro-controllers, and (2) to coordinate inter-connected micro-controllers in “the Internet of Things”. Indeed, new capabilities are added on a per-application basis and interactions are mainly limited to bespoke, point-to-point protocols that target the hardware I/O rather than the services provided by this hardware. In this paper we present the Arduino Service Interface Programming (ASIP) model, a new model that addresses the issues above by (1) providing a “Service” abstraction to easily add new capabilities to micro-controllers, and (2) providing support for networked boards using a range of strategies, including socket connections, bridging devices, MQTT-based publish–subscribe messaging, discovery services, etc. We provide an open-source implementation of the code running on Arduino boards and client libraries in Java, Python, Racket and Erlang. We show how ASIP enables the rapid development of non-trivial applications (coordination of input/output on distributed boards and implementation of a line-following algorithm for a remote robot) and we assess the performance of ASIP in several ways, both quantitative and qualitative

Taking Arduino to the Internet of things: the ASIP programming model

Micro-controllers such as Arduino are widely used by all kinds of makers worldwide. Popularity has been driven by Arduino’s simplicity of use and the large number of sensors and libraries available to extend the basic capabilities of these controllers. The last decade has witnessed a surge of software engineering solutions for “the Internet of Things”, but in several cases these solutions require computational resources that are more advanced than simple, resource-limited micro-controllers. Surprisingly, in spite of being the basic ingredients of complex hardware–software systems, there does not seem to be a simple and flexible way to (1) extend the basic capabilities of micro-controllers, and (2) to coordinate inter-connected micro-controllers in “the Internet of Things”. Indeed, new capabilities are added on a per-application basis and interactions are mainly limited to bespoke, point-to-point protocols that target the hardware I/O rather than the services provided by this hardware. In this paper we present the Arduino Service Interface Programming (ASIP) model, a new model that addresses the issues above by (1) providing a “Service” abstraction to easily add new capabilities to micro-controllers, and (2) providing support for networked boards using a range of strategies, including socket connections, bridging devices, MQTT-based publish–subscribe messaging, discovery services, etc. We provide an open-source implementation of the code running on Arduino boards and client libraries in Java, Python, Racket and Erlang. We show how ASIP enables the rapid development of non-trivial applications (coordination of input/output on distributed boards and implementation of a line-following algorithm for a remote robot) and we assess the performance of ASIP in several ways, both quantitative and qualitative