Design and Performance Evaluation of Cloud-Based XML Publish/Subscribe Services

XML message filtering and routing have been recognized as a standard for data exchange for XML dissemination services. These services are often realized using the Publish/Subscribe (pub/sub) model. The Pub/sub model is commonly used by various web-based systems, such as Web content syndication, RSS feeds, location-based services. Conventional XML filtering and forwarding is an application-layer multicast approach that relies on XML-capable brokers. Those XML-capable brokers are built above the network layer using an overlay model for message dissemination. Such an overlay model introduces a great deal of overhead in terms of initial deployment and subsequent operational cost for those XML-capable brokers that typically are supported by Internet Service Providers (ISPs). In other words, those XML-capable brokers need to be set up across geographically distributed areas and may need to be deployed and maintained even by multiple ISPs or special providers. This paper presents a XML message dissemination system using both the conventional XML multicast model and the peer model executing on a cloud, that can be deployed rapidly without the need of any ISP or special arrangements of physical brokers across the networks. In addition, changes to software deployed in the cloud can be made directly and easily. The paper demonstrates experiments over the Amazon EC2 clouds spanning different geographical locations. In addition, the paper presents a performance comparison between the conventional XML multicast model and the peer model deployed on a cloud.