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. 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 ESB profile of WSO2 EI. For ideas on how to design your integrations, and to get step-by-step instructions using example scenarios, see Enterprise Integration Patterns with WSO2 Enterprise Integrator. You can then refer back to this guide for details on the mediators used in the scenarios, how to work with endpoints and proxy services, and so on.