NodeInAction

OSI Model Intro. This is discussed so that, 1. Node's non blocking IO model can be fully understood. 2. Node's middleware concept can be explained. INTRO: 1. In the OSI model, control is passed from one layer to the next, starting at the application layer (Layer 7) in one station, and proceeding to the bottom layer, over the channel to the next station and back up the hierarchy.  2. The OSI model takes the task of inter-networking and divides that up into what is referred to as a vertical stack that consists of the following 7 layers. References Used: 1. https://www.webopedia.com/quick_ref/OSI_Layers.asp#OSI-7 2.  https://en.wikipedia.org/wiki/OSI_model <--Previous   Next-->

7 Layers In Detail 7 Layers In Detail Layer 7 Layer 7 1. OSI Model, Layer 7, supports application and end-user processes.  2. Communication partners are identified, quality of service is identified, user authentication and privacy are considered, and any constraints on data syntax are identified.  3. Everything at this layer is application-specific.  4. This layer provides application services for file transfers, e-mail, and other network software services. WWW browsers, NFS, SNMP, Telnet, HTTP, FTP Layer 6 1. Provides independence from differences in data representation (e.g., encryption) by translating from application to network format, and vice versa.  2. Works to transform data into the form that the application layer can accept.  3. Formats and encrypts data to be sent across a network, providing freedom from compatibility problems.  4. It is sometimes called the syntax layer. encryption, ASCII, EBCDIC, TIFF, GIF, PICT, JPEG, MPEG, MIDI Lay