Open System Interconnection (OSI)
The OSI Model is a logical & conceptual model
that defines network communication used by systems open to interconnection and
communication with other systems.
Layer-1 (Physical Layer) –
Its consist of hardware
which is require Ethernet & Serial technology.
RJ45, BNC, 10B2, 10BT, HUB, CAT4/5/6 this are use in
Ethernet technology.
RS323, RS422, V.35 this are use in Serial
technology.
Layer-2(DATA Link)-
Its use to understand
communication between two devices.
In Ethernet technology 802.2, 802.3, ARPA,CSMA/CD
this protocol is use.
Serial technology PPP, HDLC, Frame-Relay, ATM, X.25 this
protocol is use.
Layer-3 (Network Layer)-
Network layer is for
updating routing protocol.
Router exchange information router to router to
reach the destination.
Protocol is use- RIP, EIGRP,ISIS, OSPF, BGP, IGRP.
Layer-4 (Transport Layer)-
The role of transport
layer is transmit & receive the data.
The data flow from Application to Presentation,
presentation to session & session to transport layer.
Transport layer transmit the data with the help of
TCP & UDP.
Sliding window is perform in Transport layer.
Layer-5 (Session layer)-
Session layer is use to
establish, maintain and disconnect between two devices.
This layer allows a process to add checkpoints which
are considered as synchronization points into the data.
These synchronization point help to identify the
error so that the data is re-synchronized properly, and ends of the messages
are not cut prematurely and data loss is avoided.
The session layer allows two systems to start
communication with each other in half-duplex or full-duplex.
Layer-6 (Presentation layer)-
Presentation layer is
known as Translation layer.
This layer is for Compression, decompression,
encryption, decryption of the data if only tool is allow.
Layer-7(Application layer)-
Application layer is use
by User to perform the task like Telnet, HTTP, WWW, FTP etc.
If the user want to file transfer it can use FTP
If user want remote access its use Telnet.
