Enterprise Application Integration (EAI) is key to connecting business applications with heterogeneous systems. Over the years, architects of integration solutions have invented their own blend of patterns in a variety of ways. But most of these architectures have similarities, initiating a set of widely-accepted standards in architecting integration patterns. Most of these standards are described in the Enterprise Integration Patterns Catalog available at: http://www.eaipatterns.com/toc.html.
You can simulate most of the patterns in the catalog using various constructs of the WSO2. For step-by-step instructions using example scenarios, refer our Integration Patterns Guide at Integration Patterns with WSO2 ESB.