osi layers.pdf

OSI
Open system interconnction
Layers

1. Layer
No.
Layer name Responsibility Information
Form
Device
7 Application
layer
• It provides user interface
and supports various
services such as e-mail, file
transfer, and access to the
World Wide Web.
Message -
6 Presentation
Layer
• Presentation layer serves
like a translator & takes
care that the data is sent in
such a way that the
receiver will understand
the information
Message -
5 Session Layer • It acts as the dialog
controller for the network.
Its job includes establishing,
maintaining, synchronizing,
and lastly terminating the
interaction among the
devices that communicate
with each other.
Message Gateway
4 Transport
Layer
• Take service from network
layer and provide it to
application layer
Segment Firewall
3 Network
Layer
• Transmission of data from
host to other in another
network
Packet Router
2 Data Link
Layer
• It provides functional and
procedural methods of
transferring data between
two points.
Frame Switch, Bridge

2. • This layer is responsible for
transferring frames from
one device to another,
without errors
1 Physical Layer • It is responsible for
transmission of data
between sending &
receiving devices.
• It also defines the means of
transmitting raw bits over
the transmission media
Bits Hub, Repeater,
Cables