Shulou(Shulou.com)06/01 Report--

OSI model

Data unit

Layer (layer)

Features and common protocols

Host layer

Data

data

Application layer

Application layer

Network processes to applications, for specific application environments.

HTTP,HTTPS,FTP,SSH,SMTP

Presentation layer

Presentation layer

Data presentation layer for encryption or decryption of data

Session layer

Session layer

Communication between hosts, managing application communication

Segments

Data segment

Transport layer

Transport layer

Send packets at network nodes

TPC UDP

Media layer

Network packet / Datagram

Network layer

Network layer

Assign, route, and IP among the nodes of the network. Send messages (ip addressing), blocking control. IP, ICMP

Bit/Frame

Data frame

Data Link layer

Data link layer

A reliable point-to-point data straight-chain multi-access addressing

Ethernet,Token Ring, PPP, Frame Relay

Bit

(bits)

Physical layer

Physical layer

An unreliable straight chain of peer-to-peer data.

Define electrical and mechanical characteristics.

OSI (open system interconnection reference modle) Open Systems Interconnection Communication reference Model. Abbreviated as: OSI model. It is a network standard framework for interconnecting computers put forward by the International Organization for Standardization (ISO). It is divided into seven layers: physical layer, data link layer, network layer, transport layer, session layer, presentation layer, application layer.

To put it simply: it is the process that data on one computer is transmitted on the network through packages with additional protocols to another computer on the network; another computer includes the process that each network device arriving at it uses the various protocols of the sender (combined with the platform that supports the protocol) to unpack the package.

A practical IPS (internetprotocol Suite Internet Protocol Family) has been developed on the basis of OSI model.

IPS is an Internet communication model and the infrastructure of the Internet, which is generally called TCP/IP protocol. Because. Internet protocol family, the two core protocols, TCP (Transmission Control Protocol) and IP (Internet Protocol)

The TCP/IP protocol provides a point-to-point link transmission mechanism that standardizes how data is encapsulated, addressed, transmitted, routed, and received at the destination address. Supports underlying protocols such as ethernet (Ethernet) ppp (Point-to-Point Protocol) frame relay (frame Relay) (token ring) token ring. The entire TCP/IP protocol is responsible for solving how data passes through many peer-to-peer pathways (a peer-to-peer path, commonly known as hop). 1 hop) this allows different network members to create mutual data paths on the basis of many hops.

The TCP/IP model is abstracted into four levels and is usually regarded as a simplified OSI7 layer model.

A brief description of the layers of TCP/IP Model and its Operation Protocol

Application layer application layer (equivalent to 5-7 of OSI)

HTTP, FTP,DNS,https

Transport layer transport layer (equivalent to 4 of OSI)

TCP UDP

Internet layer Internet layer (equivalent to 3 of OSI)

IP

Link layer network interface layer (equivalent to 1-2 of OSI)

Ethernet,token Ring

The foundation of this model is to carry the transmission in TCP/UDP mode on the basis of ip; the application runs on TCP/UDP.

Protocols that can run on (connection-oriented) TCP (Transmission Control Protocol): http, https, dns, smtp, telent...

Can run on (connectionless packet transmission) UDP (user Datagram Protocol) protocols: ntp, dhcp,bootp... .

Let's take a look at his package.

Take the encapsulation of a UDP transmission as an example

Data

Application layer

UDP header

UDP data

Transport layer

IP header

IP data

Network layer

Frame header

Frame data

Frame footer

Data link layer

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