A Cloud Infrastructure for Multimedia Conferencing Applications

Conferencing enables the conversational exchange of media between several parties. Conferencing applications are among important enterprise applications nowadays. However, fine grained scalability and elasticity remain quite elusive for multimedia conferencing applications, although they are key to efficiency in the resource usage. Cloud computing is an emerging paradigm for provisioning network, storage, and computing resources on demand using a pay-per-use model. Cloud-based conferencing services can inherent several benefits such as resource usage efficiency, scalability and easy introduction of different types of conferences. This thesis relies on a recently proposed business model for cloud-based conferencing. The model has the following roles: conferencing substrate provider, conferencing infrastructure provider, conferencing platform provider, conferencing service provider, and broker. Conferencing substrates are generally atomic and served as elementary building blocks (e.g. signalling, mixing) of conferencing applications. They can be virtualized and shared among several conferencing applications for resource efficiency purposes. Multiple conferencing substrates provided by different conferencing substrate providers can be combined to build a conferencing service (e.g. a dial-out signalling substrate and an audio mixer substrate can be composed to build a dial-out audio conference service). This thesis focuses on the conferencing infrastructure provider and conferencing substrate provider roles. It proposes a virtualized cloud infrastructure for multimedia conferencing applications. This infrastructure relies on fine grained conferencing substrates (e.g. dial-out signalling, dial-in signalling, audio mixer, video mixer, floor control, etc.) and offers several advantages in addition to fine grained scalability and elasticity (e.g. assembling substrates on the fly to build new conferencing applications). An architecture is proposed to realize the roles of conferencing infrastructure provider, conferencing substrate provider and their interactions. A resource allocation mechanism for conferencing substrates is also proposed. We have also built a prototype with Xen as the virtualization platform and validated the architecture. Performance has also been evaluated

A Cloud-Based Architecture for Multimedia Conferencing Service Provisioning

Multimedia conferencing is the real-time exchange of multimedia content between multiple parties. It is the basis of several interactive multiuser applications, such as distance learning and multimedia multiplayer online games. The cloud-based provisioning of the conferencing services on which these applications rely on can have several benefits, including the easy provisioning of new applications, efficient use of resources, and elastic scalability. This paper proposes a holistic cloud-based architecture for conferencing service provisioning, which covers both the infrastructure and platform layers of the cloud. The proposed infrastructure layer offers conferencing substrates-as-a-service (e.g., dial-in signaling, video mixing, and audio mixing), instead of virtual machines or containers. The platform layer abstracts the details of the conferencing concepts and offers a high-level interface to simplify conference service provisioning for a wide range of service and application providers (experts versus non-experts). It also enables the on-the-fly scaling of the running conferences while guaranteeing the required quality of service, enables substrates composition to create new conferencing services, and eases the reuse of conferencing services in building new applications. The presented architecture is supported by a proof-of-concept prototype and performance measurements. The latter provides the analysis of resource allocation efficiency and response time, as well as the scalability of the system under suboptimal and over-provisioned conditions. It also provides recommendations for service providers regarding the best alternatives for provisioning their service

Architectures and Algorithms for Cloud-Based Multimedia Conferencing

Multimedia conferencing is the real-time exchange of multimedia content between multiple parties. It is the basis of several applications, such as distance learning, online meetings, and massively multiplayer online games. Cloud-based provisioning of multimedia conferencing has several benefits, like resource efficiency, elasticity, and scalability. However, it remains very challenging. A challenge, for instance, is the lack of holistic architectures which cover both the infrastructure and the platform layers of cloud-based multimedia conferencing applications. Another challenge is the lack of appropriate algorithms for resource allocation in the conferencing cloud to accommodate the fluctuating number of participants, while meeting the required quality of services (QoS). Yet another example is the lack of suitable algorithms for scaling the multimedia conferencing applications in the cloud while meeting both QoS requirements and cost efficiency objective. Unfortunately, the solutions proposed so far do not address these challenges. This thesis focuses on the architectural and algorithmic challenges of cloud-based multimedia conferencing. It proposes architectural components and interfaces for multimedia conferencing application provisioning, covering both the Platform-as-a-Service (PaaS) and the Infrastructure-as-a-Service (IaaS) layers. The proposed interfaces simplify multimedia conference service provisioning for a wide range of application providers. On the algorithmic side, it proposes resource allocation mechanisms that support scalability in terms of the number of participants while meeting the QoS. These mechanisms allocate the actual resources (e.g., CPU, RAM, and storage) in an optimal manner. Besides these mechanisms, it proposes the scalability approaches for cloud-based multimedia conferencing applications. To ensure cost efficiency, these proposed solutions enable fine-grained scalability of the applications with respect to the number of participants while considering the QoS requirements. All algorithmic problems in this thesis are formulated using the Integer Linear Programming (ILP) and heuristics have been designed and validated to solve them

dOTM: a mechanism for distributing centralized multi-party video conferencing in the cloud

One of the key factors for a given application to take advantage of cloud computing is the ability to scale in an efficient, fast and reliable way. In centralized multi-party video conferencing, dynamically scaling a running conversation is a complex problem. In this paper we propose a methodology to divide the Multipoint Control Unit (the video conferencing server) into more simple units, broadcasters. Each broadcaster receives the media from a participant, processes it and forwards it to the rest. These broadcasters can be distributed among a group of CPUs. By using this methodology, video conferencing systems can scale in a more granular way, improving the deployment

A Cloud Platform-as-a-Service for Multimedia Conferencing Service Provisioning

Multimedia Conferencing is the real-time exchange of media content (e.g. voice, video and text) between multiple participants. It is the basis of a wide range of conferencing applications such as massively multi-player online games and distance learning applications. For faster development as well as cost efficiency, developers of such conferencing applications can use conferencing services (e.g. dial-in audio conference) provided by third-parties. However, the third-party service providers face several challenges with respect to conferencing service provisioning (i.e. service development, deployment and management). One challenge is mastering complex low-level details of conferencing technologies, protocols and their interactions. Another challenge is resource elasticity. Number of conference participants varies during runtime. So resource utilization in an elastic manner is a critical factor to achieve cost efficiency. Cloud Computing can help tackle these challenges. It is a paradigm for swiftly provisioning a shared pool of configurable resources (e.g. services, applications, network and storage) on demand. It has three main service models: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). Using a PaaS, service providers can provision conferencing services easily and offer them as SaaS. Nonetheless, cloud-based provisioning of conferencing services still remains a big challenge due to the shortcomings of existing PaaS. In this thesis, a PaaS architecture for conferencing service provisioning is proposed. It is based on a business model from the state of the art. It relies on conferencing IaaSs that, instead of VMs, offer conferencing substrates (e.g. dial-in signaling, video mixer and audio mixer). The conferencing PaaS enables composition of new conferences from substrates on the fly. Moreover, it provides conferencing service providers, who are experienced in programming, with high-level interfaces to abstract the internal complexities of conferencing. In order for PaaS to scale ongoing conferences elastically, an algorithm is also presented in this thesis. The conferencing PaaS is prototyped and performance measurements are made. The proposed algorithm’s performance is also evaluated

System Integration for Medical Data Dissemination and Multimedia Communication in the Implementation of Tele-ECG and Teleconsultation

One of the options to extend medical services coverage is deploying a telemedicine system, where medical personnel make use of ICT (Information and Communication Technology) to overcome distance and time constraints. The implementation of telemedicine systems in Indonesia faces challenges posed by the lack of ICT infrastructure availability, such as communication networks, data centres, and other computing resources. To deal with these challenges, a telemedicine innovation needs to produce a modular and flexible system that is adaptive to medical services needed and the available ICT infrastructure. This paper presents research and development of a telemedicine system prototype for tele-electrocardiography (tele-ECG) and teleconsultation. The contributions offered are integrating system from various open-source modules and the system operational feasibility based on its function and performance. The research is conducted on a testbed which represents various components involved in the telemedicine system operation. Experiments are carried out to assess the system functionality and observe whether tele-ECG and teleconsultation reach their expected performance. Experiment results show that the system works properly and recommend several multimedia communication modes to achieve the target quality based on the available network bandwidth

Design and evaluation of automatic workflow scaling algorithms for multi-tenant SaaS

Current Cloud software development efforts to come up with novel Software-as-a-Service (SaaS) applications are, just like traditional software development, usually no longer built from scratch. Instead more and more Cloud developers are opting to use multiple existing components and integrate them in their application workflow. Scaling the resulting application up or down, depending on user/tenant load, in order to keep the SLA, no longer becomes an issue of scaling resources for a single service, rather results in a complex problem of scaling all individual service endpoints in the workflow, depending on their monitored runtime behavior. In this paper, we propose and evaluate algorithms through CloudSim for automatic and runtime scaling of such multi-tenant SaaS workflows. Our results on time-varying workloads show that the proposed algorithms are effective and produce the best cost-quality trade-off while keeping Service Level Agreements (SLAs) in line. Empirically, the proactive algorithm with careful parameter tuning always meets the SLAs while only suffering a marginal increase in average cost per service component of approximate to 5-8% over our baseline passive algorithm, which, although provides the least cost, suffers from prolonged violation of service component SLAs

BRAHMA : an intelligent framework for automated scaling of streaming and deadline-critical workflows

The prevalent use of multi-component, multi-tenant models for building novel Software-as-a-Service (SaaS) applications has resulted in wide-spread research on automatic scaling of the resultant complex application workflows. In this paper, we propose a holistic solution to Automatic Workflow Scaling under the combined presence of Streaming and Deadline-critical workflows, called AWS-SD. To solve the AWS-SD problem, we propose a framework BRAHMA, that learns workflow behavior to build a knowledge-base and leverages this info to perform intelligent automated scaling decisions. We propose and evaluate different resource provisioning algorithms through CloudSim. Our results on time-varying workloads show that the proposed algorithms are effective and produce good cost-quality trade-offs while preventing deadline violations. Empirically, the proposed hybrid algorithm combining learning and monitoring, is able to restrict deadline violations to a small fraction (3-5%), while only suffering a marginal increase in average cost per component of 1-2% over our baseline naive algorithm, which provides the least costly provisioning but suffers from a large number (35-45%) of deadline violations

A Semantic-Oriented Description Framework and Broker Architecture for Publication and Discovery in Cloud Based Conferencing

Cloud computing is an emerging paradigm for provisioning network, storage, and computing resources on demand using a pay-per-use model. Conferencing is the conversational exchange of media between several parties. Cloud-based conferencing services can provide benefits such as easy introduction of different types of conferences, resource usage efficiency and scalability. A business model has been recently proposed in a position paper for cloud-based conferencing with the following roles: conference substrate provider, conference infrastructure provider, conference platform provider, conference service provider, and broker. Conference substrates are generally atomic and served as elementary building blocks (e.g. signaling, mixing) of conferencing applications. They can be virtualized and shared for resource efficiency purposes. Multiple conferencing substrates can be combined to build a conferencing service (e.g. a dial-out audio signaling conference service composed from dial-out signaling and audio mixer substrates). The focus of this thesis is to design a semantic-oriented description framework for conferencing substrates and an architecture for their publication and discovery. The description framework is made up of a description language and a cloud-based conference ontology. The conference ontology is modeled on the basis of the interacting roles in the proposed cloud-based conferencing business model. The overall publication and discovery architecture for cloud-based conference substrates is made up of three brokers and the related publication and discovery interfaces. The publication and discovery interfaces are modelled using REpresentation State Transfer (REST) interfaces. A prototype is built to demonstrate the feasibility of this architecture. The effectiveness of the architecture is also proved using the performance measurements