ISO OSI MODEL OF NETWORKING PART 2
What is ISO OSI??
Open System Interconnect/Interface is an open standard for all communication systems. OSI model is established by International Standard Organization(ISO).
This model has seven layers:
1 Application Layer: This layer is responsible for providing interface to
the application user. (directly interact with the user.)
2 Presentation Layer: This layer defines how data should be represented to the users by the host (basically design and creativity is used to attracts the users)
3 Session Layer: This layer maintains sessions between remote hosts. For example, once user/password authentication is done, the remote host maintains this session for a while and does not ask for authentication again in that time span.(example zoom link )
4 Transport Layer: This layer is responsible for end-to-end transfer of data/files between hosts.
5 Network Layer: Handles the routing and sending of data between different networks. The most important protocols at this layer are IP and ICMP.
6 Data Link Layer: This layer is responsible for reading and writing data from and onto the line. Link errors are detected at this layer.
7 Physical Layer: This layer defines the hardware, cabling wiring, power
output, pulse rate etc.
TCP/IP protocol suite //Internet Model??
Internet uses TCP/IP protocol suite, also known as Internet suite. This defines Internet Model which contains four layered architecture. This model has the following layers:
1 Application Layer: This layer defines the protocol which enables user to interact with the network. For example, FTP, HTTP etc.
2 Transport Layer: This layer defines how data should flow between hosts. Major protocol at this layer is Transmission Control Protocol (TCP). This layer ensures data delivered between hosts is in-order and is responsible for end-to-end delivery.
3 Internet Layer: Internet Protocol (IP) works on this layer. This layer facilitates host addressing and recognition. This layer defines routing.
4 Link Layer: This layer provides mechanism of sending and receiving actual data.
