Editing Denial-of-service attack (section)

====Application layer====
The [[OSI model]] (ISO/IEC 7498-1) is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into [[abstraction layer]]s. The model is a product of the [[Open Systems Interconnection]] project at the [[International Organization for Standardization]] (ISO). The model groups similar communication functions into one of seven logical layers. A layer serves the layer above it and is served by the layer below it. For example, a layer that provides error-free communications across a network provides the communications path needed by applications above it, while it calls the next lower layer to send and receive packets that traverse that path. In the OSI model, the definition of its application layer is narrower in scope than is often implemented. The OSI model defines the application layer as being the user interface. The OSI application layer is responsible for displaying data and images to the user in a human-recognizable format and to interface with the [[presentation layer]] below it. In an implementation, the application and presentation layers are frequently combined.