The document discusses the seven-layer OSI model, which provides standards for how network operating systems communicate. It defines each of the seven layers - physical, data link, network, transport, session, presentation, and application - and their functions in transmitting data packets from one host to another. The physical layer transmits raw bits, while each higher layer performs more complex functions like error checking, routing, and data formatting until the data reaches the application layer.

2. Learning Outcomes
1. Define seven layer of OSI Model
2. Define functions of each layer in OSI
Model
3. Use OSI Model to explain the
communication between two network
nodes
4. Describe data packets and frames
5. Describe two types of addressing
covered by the OSI Model

3. OSI Model?
 The OSI (Open System Interconnection) model is
developed by ISO in 1984.
 Why OSI? as a guidelines how network operating
systems communicate on a network.
 OSI model was to provide a set of design standards
for equipment manufacturers.
ISO is the organization
OSI is the model
Note:

4. 7 Layer of OSI Model
A good what to
remember the seven
layers is
All
People
Seem
To
Need
Data
Processing

5. OSI Model vs Protocol

6. Data is transmitted from (Host A) to (Host B) the data flows down the 7
Layers at Host A and across the physical media in the form of binary
data, when it arrives at Host B the data travels back up through the
seven layers on Host B.

7. An exchange using the OSI model
Host A Host B
Layer 7
Layer 6
Layer 5
Layer 4
Layer 3
Layer 2
Layer 1

8. Layer 7: Application
• DATA
• Used for applications specifically written to run over
the network
• Provides services to end user’s applications
• Does not provide services to any other OSI layer
• Example: apps are file transfer, e-mail, NetBIOS-
based applications. Example: DNS; FTP; TFTP;
BOOTP; SNMP;RLOGIN; SMTP; MIME; NFS;
FINGER; TELNET; NCP; APPC; AFP; SMB

9. Layer 6: Presentation
• DATA
• Translates from application to network format and
vice-versa (network format to application)
• Ensures info from one system’s application layer can
be read by another system
• Translates among multiple data formats
• Does encryption and decryption

10. Layer 5: Session
• DATA
• Establishes, maintains and ends sessions across the
network.
• Responsible for name recognition (identification) so
only the designated parties can participate in the
session
• Examples: are interactive login and file transfer
connections, the session would connect and re-
connect if there was an interruption; recognize names
in sessions and register names in history

11. Layer 4: Transport
 SEGMENTS
 Responsible for delivery of a message from one
process to another
 Two transport protocols: Transmission Control
Protocol (TCP) and User Datagram Protocol (UDP)
 A train is a good analogy => the data is divided into
identical units
• Example protocols: TCP, ARP, RARP, SPXNWLink,
NetBIOS / NetBEUI, ATP

12. Layer 3: Network
 PACKETS
• Determine the path for data from the source to the
destination computer. It manage switching and routing
of data packets based on network addresses concern
on PACKET ROUTING.
• Protocols: IP (Internet Protocol), IPX (Internet
Protocol Exchange)
Data H3
IP Address

13. Layer 3: Network (cont…)

14. Layer 2: Data Link
 FRAMES
 This layer is where the network packets are
translated into raw bits (example: 00110101) to be
transmitted on the physical layer.
 Responsible for transmitting frames from one node to
the next. This is also a layer that uses the most basic
addressing scheme, MAC Addresses

15. Physical Address (Mac Address) ???
MAC (Media Access Control) address is the unique hardware
address that is installed to the network card by its manufacturer

16. Layer 1: Physical
 BITS
 Physical layer defines the cable or physical medium.
 Responsible for transmitting individual bits from one
node to the next.

17. To be Continue….

18. I don’t stop when I’m tired.
I only stop when I’m done…