Convention plutôt que configuration

Convention plutôt que configuration (aussi connu sous le nom de coder par convention ; convention over configuration en anglais) est une pratique informatique qui tend à faire décroître le nombre de décisions qu'un développeur doit prendre. L'expression indique que le développeur doit seulement se concentrer sur les aspects non conventionnels de l'application. Par exemple, s'il existe un type Vente dans le modèle, la table correspondante dans la base de données se nommera implicitement ventes. Ce n'est que si l'on choisit de dévier de cette convention, par exemple pour appeler la table produit_vente, qu'il sera nécessaire d'écrire du code pour y parvenir. Lorsque la convention mise en place par l'outil de développement correspond à ce qui est correct pour l'application, on bénéficie du service sans qu'il soit nécessaire d'écrire du code ou des fichiers de configuration. Motivation Les technologies mal étudiées nécessitent de multiples fichiers de configuration, chacun av

Measuring and Managing Switch Diversity in Software Defined Networks

Maciej Leszek Kuzniar

Software Defined Networking (SDN) is a novel approach to building computer networks. Improved flexibility, simplified management and cost reduction promised by SDN makes many see it as the future of networking. The main insight of SDN is the separation of network control and configuration decisions from packet forwarding devices. This way, complex control software development becomes independent of changes in hardware traffic forwarding switches. Relying on a well-defined interface, a controller program can supervise the whole network built of many switches, produced by multiple vendors. I argue however, that this idealized vision is difficult to achieve in practice and that an SDN controller cannot treat all switches equally. There are multiple reasons why switches following the same specification are heterogeneous: unclear specification, implementation difficulties, cost, and human errors. In this dissertation, I describe a two-phase approach to handle switch diversity in SDN. First, I present systematic techniques to detect various differences between devices. SOFT is a method and a tool that uncovers functional differences in switch software. It relies on established software analysis techniques and a novel application of a constraint solver to find inputs that result in distinct behavior of two switches. Further, I design a systematic methodology for switch update performance measurements. A benchmarking tool based on this technique computes update rate characteristics of hardware switches. By additionally tracking interactions between control and data planes during the update, this methodology is capable of revealing inconsistencies showing that the switches do not follow the specification. Finally, I address the most severe issue detected. RUM, a software layer between the controller and the switches masks and fixes incorrect rule update notifications coming from faulty switches. I demonstrate the usefulness of the described solutions by analyzing existing switches. SOFT detected several inconsistencies between two open source software switches. The performance benchmark revealed errors that compromise network security. It also provided detailed switch characteristics that should be taken into account by controller developers to improve network performance. RUM prevents packet drops in a safe network update without requiring any changes to faulty switches.

EPFL2016

Measuring and Managing Switch Diversity in Software Defined Networks

Maciej Leszek Kuzniar

EPFL2016

Convention plutôt que configuration

Product Configuration Frameworks-A Survey

Measuring and Managing Switch Diversity in Software Defined Networks

Product Configuration Frameworks-A Survey

Measuring and Managing Switch Diversity in Software Defined Networks