Over the years, architects have invented a blend of integration patterns for connecting various business applications within enterprise systems. Most of these architectures have similarities, initiating a set of widely accepted standards in 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 to Enterprise Integration Patterns with WSO2 ESB.