This multi-provider cloud approach has shown to offer a flexible and highly resilient infrastructure. For example, if the broadcaster has no in-house infrastructure available, then the infrastructure is allocated entirely on utility resources – the only weak link is the physical connection to the broadcast platforms. As demand increases, the availability of utility resources enables the services to scale to meet this demand.

19.4.2  Cloud Service Deployment and Management

The PRISM service cloud is managed by the Debut auto-deployment and management infrastructure (an overview of Debut is given in [9]) that provides service, virtual machine and application deployment, monitoring and scaling. Debut operates as a cloud broker in selecting resources for services/storage/applications, as a deployment layer and as a monitor and SLA layer for deployed resources. Each deployment block (in Debut terms), which is one or more applications/services/stores, defines its deployment requirements – following the libcloud model these are defined as restrictions that specify basic items such as version of software, trusted software providers and host operating system, infrastructure requirements such as network bandwidth and firewall requirements, and locality requirements such as particular location. The restriction framework is a generic one and can easily be extended by a user to specify particular needs in a deployment. The restrictions are used to select the resources that are suitable for a deployment from the clouds that are being managed.

The Debut deployment layer performs software deployment driven again by restrictions that specify the kind of environment, such as bare metal or virtual container type, on a selected resource and either notify a user of the allocated location or link this location into other applications that use the deployed software, and thus enable a large-scale infrastructure to be composed as a series of deployments. The management layer also performs automatic service scaling and enables SLA requirements such as response time or load factors on applications or services that will trigger automatic scaling of an application/service/store.

19.5  The PRISM Deployment

The PRISM infrastructure is currently supporting a non-public content access trial with users able to access content from a range of locations and devices as illustrated in Fig. 19.8.

At its core, the PRISM infrastructure has a cloud that implements the traditional broadcasting infrastructure, as outlined earlier, that provides digital media content in terms of audio from radio broadcasts and video from TV broadcasts. This infrastructure also provides access to live streaming broadcasts for all of the supported BBC channels.

A content cloud implements a large-scale media store with associated processing capabilities and metadata indexing and search capabilities. The content store for

Fig. 19.8  The deployed PRISM cloud

supporting a traditional broadcast channel has been extended to publish content automatically along with its metadata to the on-demand content cloud. This publication is controlled by automatically applied content policies outlined earlier.

Content is accessed through content access services that provide authenticated and multiple protocol content use. The content services support direct access to media by devices using an open collection of metadata search and content transport services. In addition, the content access services support a web interface with thumbnail-based browsing and searching based on TV Anytime metadata [12]. For example, it is possible to search for a programme based on artist, title, description, language, subtitling, audio description and approximately 1,000 fields that describe the nature and lifecycle of the media content. In the current user trial, the infrastructure is actively accessed by different devices types including a prototype set-top box developed for the BBC; computers using a range of web browsers; mobile phones or computer games consoles.

The infrastructure requires user authentication when using the content services. The services use a range of access protocols such as Open ID [8], Shibboleth [11] and X509 certificates. For most users in the trial, Open ID has been the authentication mechanism of choice as it enables their current online accounts, at Google, Hotmail, Facebook, etc., to provide user authenticated access services. Once authenticated, the access services assign a user a profile that controls their access to content. Thus, the service provides role-based views of content that control all aspects of use from ability to search and the content that can be searched, to the type of delivery mechanism that can be used, such being able to download and whether the media is rights protected when downloaded.

The search and content services are designed to be multi-format and multi-pro- vider. The search query language is designed to aggregate results taken from a range of online providers as well as the content metadata taken from the broadcasting cloud. Thus, a user query can specify that searching should be across the PRISM content cloud, YouTube, Flickr as well as web sites, such as BBC News. The content services provide direct access to content within the PRISM cloud and mediated access to other providers enabling the client services to have a single point of access to content.

Over the 1.5 years of deployment, the infrastructure has managed more than 1.5 PetaBytes of content along with supporting processing and metadata.

19.6  Summary

The PRISM cloud has evolved over 3 years into a limited, non-public, dynamic content on-demand infrastructure that is supporting a trial collection of consumers. The infrastructure has managed more than 1.5 PetaBytes of data currently and its content archive grows by 30 hours of content every day. The cloud approach has proven to give a highly reliable and scalable infrastructure, which can cope with equipments and network loss

– for example, the infrastructure has coped with losing one of its large-scale content stores by automatically deploying backup resources to on-demand providers.

19.7  Content Note

The PRISM project is an R&D project and as such it is not a statement of BBC technology direction or internal infrastructure requirements – it is an experimental infrastructure that is evaluating approaches and technologies and how they might be used within a broadcasting infrastructure.

Acknowledgements  The authors acknowledge the support of the UK Technology Strategy Board under grant TP/3/PIT/6/l/15656, the EPSRC under Platform Award EP/F066139/1 and our co-researchers in QinetiQ plc and BT plc.

Many people have worked on this project and the authors wish to highlight the role of Christina Cunningham, Stephen Craig, Chris Chambers, David Butler, Tanya Beech, Gerry Robinson and the development teams at Belfast e-Science, BBC Research and Innovation, QinetiQ ISTAR, and BT (Ireland).

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