message/service aggregation and correlation, validation, intermediaries, object identity mapping, service/message aggregation, and store and forward. Modelling The ESB can support more advanced modelling capabilities such as object modelling, common business object models, data format libraries, public versus private models for business-to-business integration, and development and deployment tooling. Service level Service level indicators might need to be measured, particularly in an enterprise mission critical environment. The key indicators are availability and performance, which includes response time, throughput, and capacity. Infrastructure intelligence More advanced infrastructure capabilities can be provided. These include: ­ Business rules ­ Policy-driven behavior, particularly for service levels ­ Security and quality of service capabilities (WS-Policy) 6.2.9 Rules Directory