Voice Quality of VoIP in High Availability Environment

The development of telecommunication technology specified the Internet Protocol (IP) based technology for the next generation network. Voice over Internet Protocol (VoIP) has been introduced to overcome future telephony demand. However, these rapid changes encountered some issues, and the most critical is how to provide the services availability and reliability equally to circuit based telephony. Virtualization is widely used not only for hardware efficiency and maintenance, but also for High Availability support. Virtualized environment provides the ability among servers to migrate or replicate into another machine, even when they are running their services, which is known as Live Migration. In this paper, the voice quality of VoIP service when running on the High Availability system in virtualized environment is studied and examined. The objective analysis by using quality of services (QoS) attributes is conducted as well as the subjective analysis using Mean Opinion Score (MOS). The work utilizes Xen® Hypervisor with modified Remus extensions to provide the High Availability environment. Remus approach using checkpoint based is deployed to copy the primary server to the backup server. A range of 40ms – 900ms has been applied as time interval of checkpoint. The results show that the mean jitter is 9,98 ms, packet loss 3,12% and MOS 3.61 for Remus 400ms checkpoint. MOS with different checkpoint time interval is also presented

Snooze: A Scalable, Fault-Tolerant and Distributed Consolidation Manager for Large-Scale Clusters

International audienceIntelligent workload consolidation and dynamic cluster adaptation offer a great opportunity for energy savings in current large-scale clusters. Because of the heterogeneous nature of these environments, scalable, fault-tolerant and distributed consolidation managers are necessary in order to efficiently manage their workload and thus conserve energy and reduce the operating costs. However, most of the consolidation managers available nowadays do not fulfill these requirements. Hence, they are mostly centralized and solely designed to be operated in virtualized environments. In this work, we present the architecture of a novel scalable, fault-tolerant and distributed consolidation manager called Snooze that is able to dynamically consolidate the workload of a software and hardware heterogeneous large-scale cluster composed out of resources using the virtualization and Single System Image (SSI) technologies. Therefore, a common cluster monitoring and management API is introduced, which provides a uniform and transparent access to the features of the underlying platforms. Our architecture is open to support any future technologies and can be easily extended with monitoring metrics and algorithms. Finally, a comprehensive use case study demonstrates the feasibility of our approach to manage the energy consumption of a large-scale cluster

Merlin: A Language for Provisioning Network Resources

This paper presents Merlin, a new framework for managing resources in software-defined networks. With Merlin, administrators express high-level policies using programs in a declarative language. The language includes logical predicates to identify sets of packets, regular expressions to encode forwarding paths, and arithmetic formulas to specify bandwidth constraints. The Merlin compiler uses a combination of advanced techniques to translate these policies into code that can be executed on network elements including a constraint solver that allocates bandwidth using parameterizable heuristics. To facilitate dynamic adaptation, Merlin provides mechanisms for delegating control of sub-policies and for verifying that modifications made to sub-policies do not violate global constraints. Experiments demonstrate the expressiveness and scalability of Merlin on real-world topologies and applications. Overall, Merlin simplifies network administration by providing high-level abstractions for specifying network policies and scalable infrastructure for enforcing them