OSI Model is

Application

Presentation

Session

Transport

Network

Data Link

Physical

TCP/IP Model is

Application

Transport

Internet

Network Access

OSI Layers

Application (7)

Presentation (6)

Session (5)

Transport (4)

Network (3)

Data link (2)

Physical (1)

The OSI Model Layers and Functions Functional Description Refers to interfaces between network and application software. Also includes authentica- tion services. Defines the format and organization of data. Includes encryption. Establishes and maintains end-to-end bidirectional flows between endpoints. Includes managing transaction flows. Provides a variety of services between two host computers, including connection estab- lishment and termination, flow control, error recovery, and segmentation of large data blocks into smaller parts for transmission. Refers to logical addressing, routing, and path determination. Formats data into frames appropriate for transmission onto some physical medium. Defines rules for when the medium can be used. Defines means by which to recognize transmission errors. Defines the electrical, optical, cabling, connectors, and procedural details required for transmitting bits, represented as some form of energy passing over a physical medium.