Middleware is a software that mediates between application software and the kernel or device driver software. Middleware is an abstraction layer generally used on embedded devices with two or more applications in order to provide flexibility, security, portability, and connectivity, intercommunication, and/or interoperability mechanisms between applications. Middleware allows reducing complexity of the applications by centralizing software infrastructure that would traditionally be redundantly found in the application layer. However, in introducing middleware to a system, one introduces additional overhead, which can greatly affect scalability and performance. In short, middleware affects the embedded system at all layers.