3-Computer network Reference Model

I. OSI

The International Standards Organization (ISO) issued the Open Systems Interconnect Reference Model in 1984 OSI

Ii. implications of the OSI layer seven model

Application layer: An excuse for Web services to end users

Presentation layer: Representation of data, security, compression

Session Layer: Create, manage, and terminate sessions for example: breakpoint continuation

Transport Layer: Defines the protocol port number of the transmitted data, as well as the flow control and error checking to realize the interconnection of the program

Network layer: Logical address addressing, to achieve the choice between different networks, defines the IP address for the best path to data transmission

Data Link layer: Establish a logical connection, hardware address addressing, error checking and other functions, through the MAC address to achieve communication, frame transmission

Physical layer: Establish, maintain, disconnect physical connections, define interfaces and media, and enable the transmission of bit streams

Third, the composition of TCP/IP protocol family

Common protocols:

Application layer: FTP HTTP TFTP SMTP SNMP DNS TELNET POP3 HTTPS

Transport Layer: TCP UDP

Network layer: ICMP IGMP IP ARP RARP

Iv. process of data transmission

The process of encapsulating and sealing data

V. PDU (Protocol Data Unit)

Transport Layer Segment segment

Network Layer Packet Package

Data Link Layer Frame frame

Physical layer bit bit

3-Computer network Reference Model