Computer Network Fundamental Part 02

Computer Network Fundamental Part 02. 

ISO Model .

5. Session Layer: Its create and manage session. Example:
when we are open a browser. Its called session.
 
In the browser when open two tab. Example:
In one tab we open www.google.com
Other one we open www.youtube.com
Then At a time we search different keyword. And our result is also different.
when its worked at a time its can not block one another. For this different internet browse session layer give port number for each (url or https or browser Tab ) addresses.


4. Transport Layer: Its a big layer of ISO. End to end deliver of data from source to destination.
There are two main protocol in transport layer.
a. TCP
b. UDP

A. TCP   
1. Transmission Control protocol.
2. Acknowledgement System. Example:
when user send request(its also called sync ) google or other. Then google or other send Acknowledgement request(its mean pls again send request.)
3. Data delivery guarantee. Example:
Is data lose for any reason. TCP retransmit data again.
4. Its a connection oriented.
5. It has flow control . (when router throw many data in a one time. Then TCP control flow. its control one by one).
6. It has segmentation protocol.(Its make data big to small)
7. Sequencing and error correction .
   
B. UDP
1. User Data-gram protocol.    
2. No Acknowledgement.Example:
Direct Data send. No request, No syn .
3. No data guarantee of data delivery.
4. connection less.
5. its used audio/video chart.

Short INFO

Application
Presentation         Those are DATA.  ITS called PDU (Protocol Data Unit )
Session

The three layer PDU is Data.
When Data come in transport layer. Then transport layer make those data in small pieces.
Then we can said what is the PDU of transport layer ?
its segment.

                                                                                                                           

                (coming............)