Cyber EOP - Network Devices By Mr. B

Understanding the OSI

Model

Layers, Components, and Mnemonics for Easy Recall

OSI Model Overview

The OSI (Open Systems Interconnection) model is a conceptual framework
used to understand network interactions.

Purpose: It has 7 layers, each with distinct functions, which ensure reliable
data transmission across a network.

Multiple Choice

What does the acronym OSI stand for?

• Open Source Integration

• Operational Systems Interface

• Operational Systems Interconnect

• Open Systems Interconnection

OSI Layers and Functions

OSI Layer
Application

Presentation

Session

Transport

Purpose
API, Interface,
Application Management

Formatting, Encryption,
Compression

Authentication,
Authorization

Data Transfer Reliability

Packet Data Unit
(PDU)
Message

Message

Message

Segment (TCP),
Datagram (UDP)

Multiple Choice

Which layer is responsible for reliability in data transmission?

• Session

• Transport

• Network

• Application

Components Operating at Each OSI Layer

Application Layer (OSI) - Corresponds to the Application layer in TCP/IP. Protocols: HTTP, SMTP, etc. Devices: None.

Presentation Layer (OSI) - Corresponds to the Application layer in TCP/IP. Protocols: HTTP, SMTP, etc. Devices: None.

Session Layer (OSI) - Corresponds to the Application layer in TCP/IP. Protocols: HTTP, SMTP, etc. Devices: Gateway.

Transport Layer (OSI) - Corresponds to the Transport layer in TCP/IP. Protocols: TCP, UDP. Devices: Firewall.

Network Layer (OSI) - Corresponds to the Internet layer in TCP/IP. Protocols: IP, ICMP. Devices: Router.

Data Link Layer (OSI) - Corresponds to the Link layer in TCP/IP. Protocols: Ethernet, Wi-Fi, PPP, etc. Devices: Switch,
Bridge.

Physical Layer (OSI) - Corresponds to the Link layer in TCP/IP. Protocols: CAT 5, RJ-45, etc. Devices: Hub, NIC, Cable.

Multiple Choice

What is the main function of the Session layer?

• Data Formatting

• Routing

• Authentication and Authorization

• Data Transmission

Addressing & Troubleshooting

1.Application Layer (OSI)

○Address: None

○Troubleshooting Tool: Wireshark

2.Presentation Layer (OSI)

○Address: None

○Troubleshooting Tool: Wireshark

3.Session Layer (OSI)

○Address: None

○Troubleshooting Tools: NSLOOKUP, NBTSTAT, Wireshark

4.Transport Layer (OSI)

○Address: Port

○Troubleshooting Tools: TELNET, NETSTAT, Wireshark

5.Network Layer (OSI)

○Address: IP Address

○Troubleshooting Tools: IPCONFIG, PING, TRACERT, Wireshark

6.Data Link Layer (OSI)

○Address: MAC Address

○Troubleshooting Tool: ARP, Wireshark

7.Physical Layer (OSI)

○Address: None

○Troubleshooting Tools: Lights on Device, Cable Checks

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Multiple Choice

Which tool is commonly used for troubleshooting at the Network layer?

• NSLOOKUP

• Wireshark

• ARP

• TELNET

Mnemonics for OSI Layers (7-1)

All

People

Seem

To

Need

Data

Processing

Popular Acrostic:

●Away Pizza Sausage Throw Not Do Please

Bombal’s Suggestion:

●All People Sleeping Through Networking Don’t Pass

Multiple Choice

What is the acronym used to remember the OSI layers?

• A - All, P - People, S - Sleep, T - Through, N - Networking, D - Don't, P - Pass

• A - Always, P - Play, S - Safe, T - Together, N - Never, D - Doubt, P - People

• A - All, P - People, S - Seem, T - To, N - Need, D - Data, P - Processing

• A - Always, P - Provide, S - Support, T - To, N - New, D - Data, P - Processing

Mnemonics for OSI Layers (1-7)

1.

Please

2.

Do

3.

Not

4.

Teach

5.

Students

6.

Pointless

7.

Acronyms

India Schools Acrostic:

●Please Do Not Take Sales Person's Advice

Conclusion

Key Takeaway: Understanding the OSI model layers, components, and
mnemonics can simplify troubleshooting and network management.

Tip: Use the right mnemonic to easily recall each OSI layer in order.