Dominique Verchere

Cloud computing over telecom network

Telecom operators should configure networks with end-to-end bandwidth and latency guarantees for Cloud infrastructure as services. IT and connectivity services require to be associated in workflows handled at edge routers of wavelength switched Optical Networks.

Virtualizing and Scheduling Optical Network Infrastructure for Emerging IT Services [Invited]

Emerging IT service providers that aim at delivering supercomputing power available to the masses over the Internet rely on high-performance IT resources interconnected with ultra-high-performance optical networks. To adjust the provisioning of the resources to end-user demand variations, new infrastructure capabilities have to be supported. These capabilities have to take into account the business requirements of telecom networks. This paper proposes a service framework to offer Internet service providers dynamic access to extensible virtual private execution infrastructures, through on-demand and in-advance bandwidth and resource reservation services. This virtual infrastructure service concept is being studied in the CARRIOCAS project and implemented thanks to the scheduling, reconfiguration, and virtualization (SRV) component. This entity handles the service requests, aggregates them, and triggers the provisioning of different types of resources accordingly. We propose to adapt to envisioned heterogeneous needs by multiplexing rigid and flexible requests as well as coarse or fine demands. The goal is to optimize both resource provisioning and utility functions. Considering the options of advanced network bandwidth reservations and allocations, the optimization problem is formulated. The impacts of the malleability factor are studied by simulation to assess the gain.

Applying formal methods to PCEP: an industrial case study from modeling to test generation

This paper presents the experimental results in applying formal methods to an industrial protocol for constraint‐based path computation, called Path Computation Element Communication Protocol (PCEP). The experiments include a number of major activities in model‐based testing from modeling to test generation. From the PCEP specification defined by IETF (Internet Engineering Task Force), the functionalities of PCEP are divided into two parts: application and protocol. The protocol part of PCEP is then described in the IF (Intermediate Format) language which is based on communicating timed automata. A number of basic requirements are identified from the PCEP specification and then described as properties in IF. Based on these properties, the validation and verification of the formal specification are carried out using the IF toolset. Test cases are generated using an automatic test generation tool, called TestGen‐IF, which uses partial state space exploration guided by test purposes. As a result, some errors and ambiguities have been found in the PCEP standard specification. Copyright

Routing protocol enhancements for power state engineering of green network elements

A routing protocol is enhanced to advertise the power state of node interfaces for wavelength switched optical networks to allow tuning the power consumption according to the data traffic demands. By engineering the different power states, GMPLS controlled nodes are configured to preserve the QoS of incoming traffic volumes such as reliability as well as the constraints of carrier grade networks, such as stability and operation costs. For variable incoming traffic reference models, more than half of the total power consumption required for an European optical networks without any power saving capabilities can be saved from powering the optoelectronic interfaces column.

Performance Evaluation of a SLA Negotiation Control Protocol for Grid Networks

A framework for an autonomous negotiation control protocol for service delivery is crucial to enable the support of heterogeneous service level agreements (SLAs) that will exist in distributed environments. We have first given a gist of our augmented service negotiation protocol to support distinct service elements. The augmentations also encompass related composition of the services and negotiation with several service providers simultaneously. All the incorporated augmentations will enable to consolidate the service negotiation operations for telecom networks, which are evolving towards Grid networks. Furthermore, our autonomous negotiation protocol is based on a distributed multi-agent framework to create an open market for Grid services. Second, we have concisely presented key simulation results of our work in progress. The results exhibit the usefulness of our negotiation protocol for realistic scenarios that involves different background traffic loading, message sizes and traffic flow asymmetry between background and negotiation traffics.

Automatic Network Services Aligned with Grid Application Requirements in CARRIOCAS Project

Automatic Service framework named Scheduling, Reconfiguration and Virtualization (SRV) is developed in CARRIOCAS project to enhance existing Telecom network infrastructures for supporting grid applications sharing IT resources interconnected with ultra-high performance optical networks. From the requirements of Grid applications a classification is pro po sed to specify the network services and their attributes. In large-scale collaborative environments, SRV solution is described to enable automatic network service operations according to high-performance computing service access. The resources hosted at datacenters are virtualized to be attached to transport network infrastructure offering uniform interfaces towards external cus tomers. New level of service bindings is defined with network services du ring executions of Grid applications’ workflows. On-demand intensive com puting and visualization services scenario is described in Telecom environment.

Energy savings in dynamic and resilient optical networks based on traffic-aware strategies

An analysis of the energy savings is presented when taking into account a complete traffic model for a one-year time period. Daily and weekly traffic fluctuations as well as yearly traffic growth are considered when analyzing the power consumption. Low power mode in optoelectronic devices (sleep-mode and rate adaptive capabilities) is implemented within a traffic-aware networking approach. The impact of dedicated 1:1 protection in a dynamic network scenario is considered and a comparison is made with the unprotected case. A GMPLS control plane is implemented and used to re-configure the power-adaptive devices and connections. Results show that symbol-rate adaptation provides high savings for unprotected scenarios (37% energy savings w.r.t. unprotected Baseline), while for the protected scenarios better results are obtained for modulation format adaptation which includes sleep-mode (57.1% energy savings w.r.t. protected Baseline). Moreover, compared to the Baseline scenarios the Mixed adaptation, combining both symbol-rate and modulation format, is the most power-efficient strategy providing 39% energy savings for unprotected scenario and 70% energy savings for dedicated protection scenario.

An Autonomic Open Marketplace for Inter-Cloud Service Management

The rise of utility in cloud computing and telecommunications has introduced greater complexity in the provisioning and performance management of remote services. We propose extended management strategies for this complexity. Our overall aim is for the management to accept responsibility for the complex service in an open marketplace. Responsibility is, firstly, defined by aiming to cover the totality of modern complex services, managing both the connectivity and virtual infrastructure. Secondly, responsibility is further defined as managing risk and resilience in the provisioning and operation of the complex service. With these aims, we are working towards a bundled service provider agent architecture, which can negotiate on the open service market. This approach aims to also optimise the utilisation of the providers infrastructure while reducing the risk of failure to users through total service management. We present the specification, design and simulation of the bundled service agents in a marketplace environment.

Analysis and Optimization of Aggregation in a Reconfigurable Optical ADD/DROP Multiplexer

We analyze the performance and optimize the design of a Reconfigurable Optical ADD and DROP Multiplexer (ROADM in the following). The analysis is based on stochastic bounds, a derivation of an extension of Pollacek formula for Batch queues and numerical analysis of discrete time Markov chains.

CARRIOCAS Project: Towards Converged Internet Infrastructures Supporting High Performance Distributed Applications

The CARRIOCAS project studies and implements a high bit rate optical network capable of accommodating the requirements of data-intensive, high-performance distributed applications, in terms of bandwidth, quality of service guarantees, dynamic and automated service provisioning. The investigations are carried out under the constraints of supporting the applications on converged network infrastructures hosting other types of traffic. Distributed storage of massive volumes of data as well as collaborative high resolution remote visualization are under experimentation on a testbed. This paper analyzes the requirements brought by the applications on the network, compares different network architectures, presents the management architectures along with some resource selection optimization algorithms, and describes the testbed and tested applications.