This article picks up the previous discussion on the requirements from a multi-tenant solution for the delivery of user-generated content to designated consumers and delves into the architecture.

The architecture comprises a cloud infrastructure layer, a content service virtualization layer, and an Identity Access Management that provides authentication, authorization, and auditing. These can be integrated through an inter-cloud messaging bus that facilitates a distributed protocol for resource management, account management, content management and service orchestration.

The cloud infrastructure layer spans the public, private and personal cloud. The purpose of stretching a cloud infrastructure layer over hybrid IT resources is to form a dynamic content delivery service overlay. This overlay consists of a content distribution tree which provides 1) the required Quality-of-Service and 2) has a minimum cost. In addition to the standard storage and bandwidth required by the overlay, some computing resources are reserved for content processing, rendering and management functionalities. Each of these functionalities requires a dedicated application engine. The key module to pool all the required IT resources together is a distributed algorithm for cloud resource management. Any message-based consensus protocol could be used here such as Paxos or Raft*.

The content service virtualization layer is the one providing a suite of middleware components to support different application engines. These include:

Content distribution: which provides services for optimally distributing the content from its source to its consumers. These services are supported by content caches strategically located through the network. The distribution component. The distribution component also includes the actual mechanism and the protocols used for transmitting data over the underlying network and serving the content to the consumers.

Content processing: which provides services for sourcing and adapting content based on available bandwidth, user preferences and device capabilities. Modification and conversion also includes those for wireless devices.

Content storage: which includes modules that provision directories and artifacts for storing user generated content with security specified by the providers. The implementation of an S3 storage is a good analogy here. Functionalities include distributed secure storage, content naming, and resolution, and content replication.

Request routing: which provides services for navigating both clients’ requests to upload their contents and consumers requests to retrieve the content from the nearest and available location. The selection of this location depends on both the proximity and the availability of the system resources.

Service orchestration: which provides services for integrating different media services for internal and external service entry points. For example, a social TV application would draw a lot of individual media services such as a buddy service from social networking and a media streaming service.

The IAM and Service Bus are left out to be completed as appropriate for the above application engines.