Ldapwiki: OSI-Model

Overview[1]#

OSI-Model is a Framework for describing Communication Layers

OSI Model

OSI Model

#	Layer	Level	Protocol Data Unit (PDU)	Function
7	Application Layer	Host layer	Data	High-level APIs, including resource sharing, remote file access
6	Presentation Layer	Host layer	Data	Translation of data between a networking service and an application; including character encoding, data compression and encryption/decryption
5	Session Layer	Host layer	Data	Managing communication sessions, i.e. continuous exchange of information in the form of multiple back-and-forth transmissions between two nodes
4	Transport Layer	Host layer	Segment TCP/ Datagram (UDP)	Reliable protocol transmission of data segments between points on a network, including Packet segmentation, acknowledgement and multiplexing
3	Network Layer	Media layer	Packet	Structuring and managing a multi-node network, including addressing, routing and traffic control
2	Data-link Layer	Media layer	Frame	Reliable protocol transmission of data frames between two nodes connected by a Physical Layer
1	Physical Layer	Media layer	Bit	Transmission and reception of raw bit streams over a physical medium

Some Information Technology people have proposed we should add the Human Interconnection Model Proposed Layers

There might be more information for this subject on one of the following: