Osimodel
OSI stands for Open System Interconnection,by seeing abbreviation we can tell that it is used to fascilitate communication between systems.
it has 7 layers
protocols in each layer goverrns the data commuincation
| 1.Application Layer |
|---|
| 2.Presentation Layer |
| 3.Session Layer |
| 4.Transport Layer |
| 5.Network Layer |
| 6.Datalink Layer |
| 7.Physical Layer |
the upper 4 layers are taken care by os,the lower 3 layers taken care by network
Data from sender computer goes from layer 1-7
data to reciver’s computer comes from layer 7-1
each layer interact with its adjascent layers
lets discuss about each layer for more understanding
| application Layer | This is where user interact with applications which works with internet, ex:web browser,by using application we can generate data given to below layers,protocols works on this layer http,smtp…etc |
|---|---|
| Presentation Layer | does encryption(optional) ,trnsalation(convert data into common format),compression(used for multimedia data) to data whatever needed,it will mainly focus on presenting data |
| Session Layer | responsible for create ,mange,terminate sessions |
| Transport Layer | responsible for end-to-end communication between the two devices,connection control(connection oriented:before send data conection created,connetion less: data sent as such),port addressing(adding src,dest ports),breaks big messages into smaller and combines all smaaler to big message(segmentation & reassembly),protocols:tcp,udp |
| Network Layer | Ip addressing(adding src,dest ip),routing |
| Datalink Layer | responsible for moving data from one node to other,framing,mac addressing(adding src,dest mac) protocols:ethernet,wifi |
| Physical Layer | all data from above layers converted to bits here transmit over a medium,all media fall in this layer |
Written on April 21, 2023