This document specifies the semantics and the structure of the Virtual private eXecution infrastructure Description Language (VXDL). VXDL is an XML-based language that enables Virtual Private eXecution Infrastructure (ViPXi) description. A ViPXi is a time-limited organized aggregation of heterogeneous computing and communication resources. VXDL allows users to specify virtual resources, virtual network’s topology and timeline representation.



Current version:

  1. -Specification, version 2.5

The Virtual private eXecution infrastructure Description Language (VXDL) is a language that allows the description of a Virtual Private eXecution Infrastructure (ViPXi) or a resources graph. A VIPXI is a time-limited organized aggregation of heterogeneous computing and communication resources. It means interconnected end resources for data processing or storage, but also the network’s topology, including communication equipments and timeline representation. The ViPXi concept and its associated VXDL description language brings two original aspects to the infrastructure as a service paradigm (IaaS), both related to the networking aspects: (i) the joined specification of network elements and computing elements and (ii) the link-organization concept, which permits a simple and abstract description of complex structures. The VXDL language mainly aims at enabling the description of resources and networks that are virtual (dematerialized) but are also, to some extend, adaptable to physical ones.

1 - Introduction

ViPXis are complex objects that have lifetime (composition, reservation, activation, migration, pause, store, and reactivate operations). For example, users need to define the virtual private execution infrastructures they request according to the applications’ requirements. To facilitate the specification and the manipulation of these objects we propose a simple open language.A descriptive language dedicated to virtual infrastructures description must be abstract enough and more adaptive than conventional resource description languages. In particular, it needs to combine the space and temporal aspects of virtual infrastructures. During the specification process, new challenges coming from virtualization techniques have to complement the management, configuration and execution features of classical infrastructure description languages. We identify some desirable aspects that must be integrated in such language:

•    Each resource must be characterized using an extensible list of descriptive parameters to represent the necessary configuration (e.g., memory, CPU speed, and storage capability); Some system will not be able to process these parameter while others would be;

•    Each component (individually or in-group) should be characterized by its elementary function, for example to describe a set of computing node

s or storage nodes; this would be exploited by system able to propose equivalent services;

•     Recursive representation of individual resources and groups are necessary;

•    Software (e.g., operating systems) and tools (e.g., communication and programming tools) that must be deployed and configured in each component have to be specified. This increases the automation level;

•    The virtual network topology has to be expressed, with the detail of each virtual link. On the other hand, parameters should enable an abstract description, for example, informing a virtual link description that must be used to interconnect a group of resources;

•    The executing timeline of the infrastructure (this parameter should help in resources reservation and co scheduling);

•     Security attributes for each resource element (access control, confidentiality level);

•     Commercial attributes for each resource element (maximum cost);

•     Identification of critical components, which requires fault tolerance protection;

•     Temporal attributes for each resource element (time window for provisioning).

2 - Needs for a language to specify virtual infrastructures