The document discusses the OSI model, which defines a standard framework for network communication. It breaks communication into 7 layers, with each layer providing specific services to the layers above and below. The layers are physical, data link, network, transport, session, presentation, and application. The model provides abstraction and modularity to simplify network protocol design and ensure interoperability between different network equipment and technologies.

2. OSI MODEL
akshit panchal-171080107015
tasveer Rajput-171080107014

3. WHAT IS OSI MODEL?
 The Open Systems Interconnection (OSI) Model is a conceptual and logical layout that defines
network communication used by systems open to interconnection and communication with other
systems.
 The model is broken into seven subcomponents, or layers, each of which represents a conceptual
collection of services provided to the layers above and below it. The OSI Model also defines a
logical network and effectively describes computer packet transfer by using different layer
protocols.
 The OSI Model may also be referred to as the seven-layer OSI Model or the seven-layer model.

4. SEVEN-LAYERS OF OSI MODEL
 Upper layers-
7)application layer
6)presentation layer
5)session layer
 Lower layers-
4)transport layer
3)network layer
2)data link
1)physical layer

5. APPLICATION LAYER
 OSI Model, Layer 7, supports application and
end-user processes.
 Communication partners are identified,
quality of service is identified, user
authentication and privacy are considered,
and any constraints on data syntax are
identified.
 Everything at this layer is application-
specific. This layer provides application
services for file transfers,email and other
files.

6. PRESENTATION LAYER
 This layer provides independence from
differences in data representation
(e.g., encryption) by translating from
application to network format, and vice
versa.
 The presentation layer works to transform
data into the form that the application layer
can accept.
 This layer formats and encrypts data to be
sent across a network.

7. SESSION LAYER
 This layer establishes, manages and
terminates connections between applications
 The session layer sets up, coordinates, and
terminates conversations, exchanges, and
dialogues between the applications at each
end.

8. TRANSPORT LAYER
 OSI Model, Layer 4, provides transparent
transfer of data between end systems,
or hosts, and is responsible for end-to-end
error recovery and flow control.
 It ensures complete data transfer.

9. NETWORK LAYER
 Layer 3
provides switching and routing technologies,
creating logical paths, known as virtual
circuits, for transmitting data from node to
node. Routing and forwarding are functions
of this layer, as well as addressing
, internetworking, error handling, congestion
control and packet sequencing.

10. DATA LINK LAYER
 At OSI Model, Layer 2, data packets
are encoded and decoded into bits.
 The data link layer is divided into two sub
layers: The Media Access Control (MAC)
layer and the Logical Link Control(LLC) layer.
 The MAC sub layer controls how a computer
on the network gains access to the data and
permission to transmit it.
 The LLC layer controls frame synchronization,
flow control and error checking.

11. PHYSICAL LAYER
 OSI Model, Layer 1 conveys the bit stream -
electrical impulse, light or radio signal —
through the network at the electrical and
mechanical level.
 It provides the hardware means of sending
and receiving data on a carrier, including
defining cables, cards and physical aspects.

12. BENEFITS OF OSI MODEL;
 Seperating the network communication into smaller pieces , the osi model simplifiesrs how
network protocol designed.
 The osi model was designed to ensure different types of equipment(such as network adapters ,
hubs and routers , etc ….)

13. ADVANTAGES OF OSI MODEL
 It is a truly generic model. And it is considered as a standard model in computer networking
 Layers in OSI model architectures are distinguished according to the services, interfaces, and
protocols.
 It is more secure and adaptable than having all services bundled in a single layer.
 This layered architecture follows abstraction principle. Change in one layer does not impact
much on other layers

14. DISADVANTAGES OF OSI MODEL
 It doesn’t define any particular protocol.
 It may find sometimes difficult to fit a new protocol in this model. This is because this model was
created before the invention of any of these protocols.
 The session layer is used for session management. Presentation layer deals with user interaction.
Though they are useful, not as much as other layers in the OSI model.
 There is some duplication in services at various layers.
 Such as, both transport and data link layer have error control mechanisms.