英語復(fù)習(xí):OSI is a theoretical model that shows how any two different systems can communicate with e
OSI is a theoretical model that shows how any two different systems can communicate with each other.Router, as a networking device, operate at the ( ) layer of the OSI model.
A、transport
B、application
C、network
D、physical
OSI是兩個(gè)不同系統(tǒng)相互通信的理論模型。路由器是運(yùn)行在OSI中網(wǎng)絡(luò)層的網(wǎng)絡(luò)設(shè)備。
Open System Interconnect(OSI):開放式系統(tǒng)互聯(lián)
theoretical model:理論模型
Router:路由器
networking device:網(wǎng)絡(luò)設(shè)備
physical layer:物理層
data Link:數(shù)據(jù)鏈路層
network layer:網(wǎng)絡(luò)層
transport layer:傳輸層
session:會(huì)話層
presentation:表示層
Application layer:應(yīng)用層
國(guó)際標(biāo)準(zhǔn)化組織(ISO)制定了OSI模型。這個(gè)模型把網(wǎng)絡(luò)通信的工作分為七層,分別是物理層、數(shù)據(jù)鏈路層、網(wǎng)絡(luò)層、傳輸層、會(huì)話層、表示層和應(yīng)用層。
網(wǎng)線 、光纖、同軸電纜、雙絞線、中繼器和集線器是物理層,網(wǎng)橋、網(wǎng)卡、二層交換機(jī)是數(shù)據(jù)鏈路層,路由器和三層交換機(jī)是網(wǎng)絡(luò)層。
物理層的數(shù)據(jù)單位是比特bit;
數(shù)據(jù)鏈路層的數(shù)據(jù)單位是幀F(xiàn)rame;
網(wǎng)絡(luò)層的數(shù)據(jù)單位是包Packet;
傳輸層的數(shù)據(jù)單位是段Segment。