Solution:-
OSI means open System Interconnect
model. It was developed by the International organization for standardization
in 1974. It consists of seven layer, each layer has specific processing
function. Figure below.......
1. Application layer: It is responsible for providing network services to the user. It is also known as desktop layer.
2. Presentation layer: It is responsible for concerting data
into standard format. eg. ASCII, JPG, MPG, BMP.
3. Session layer: It is responsible for establishing
maintaining and terminating session. Session ID work at session layer.
RPC- Remote
procedure call
SQL- Structured
query language
NFS- Network
File System
4. Transport layer: It is responsible for end- to- end
connectivity. It is also known as the heart of OSI layers. Following tasks are
performed at transport layer:
i. Indentifying service
ii. Multiplexing and
De-multiplexing
iii. Segmentation
iv. Sequencing and reassembling
v. Error correction
vi. Flow control
5. Network layer: It is responsible for providing best
path for data to reach the destination. Logical addressing works on this layer.
Router is a Network layer device.
6. Data link layer: It is divided into two sub layers.
a. LLC:
Logical link control which talks about WAN protocols.
b. MAC: Media
Access Control which talk about physical address. It is responsible for error
detection also.
7. Physical layer:
It is responsible for electrical mechanical and procedural checks. Data
will be converted into Binary (i.e.) O's and I's devices working at physical
layer are Hubs, Repeaters, cable, Modem etc.
