Seven-layer Model of OSI Network and its explanation
The following is a seven-layer model of OSI drawn using Emacs's artist-mode. You can remember it in one sentence. I don't remember where I saw it. It's probably "All People Seem To Need Data Process".
# + BEGIN_SRC ditaa: file p_w_picpaths/network01.png +-+ | cRED Application | +-+ | cPNK Presentation | +- -+ | cYEL Session | +-+ | cBLU Transport | +-+ | cGRE Network | +- -- + | c1AC DataLink | +-+ | c1AB Physical | +-+ # + END_SRC
The details of each layer are as follows:
Layer 7: the application layer defines the interface for communication and data transmission in the network-user programs
Provide standard services, such as transfer and processing of virtual terminals, files, and tasks
Layer 6: the presentation layer masks the differences in data formats between different systems
Specify the data transfer format for stand-alone structures
Encoding and decoding of data; encryption and decryption; compression and decompression
Layer 5: session layer manages user sessions and conversations
Control the establishment and hang-up of logical connections between users
Report an error that occurred at the upper level
Layer 4: the transport layer manages end-to-end information transmission in the network
Provide reliable and orderly packet delivery through error correction and flow control mechanisms
Provides delivery of connectionless packets
Layer 3: the network layer defines how data is transmitted between network devices
Route packets based on a unique network device address
Provide flow and congestion control to prevent the loss of network resources
Layer 2: the data link layer defines the program that operates the communication connection
Encapsulate a packet into a data frame
Monitor and correct packet transmission errors
Layer 1: the physical layer defines the physical way to send data through network devices
As an interface between network media and devices
Define optical, electrical, and mechanical properties.
