OSI Layers Flashcards
How many layers are in the OSI Model?
7 Layers
What are the seven layers of the OSI Model?
Physical, Data-link, Network, Transport, Session, Presentation, Application (Please Do Not Throw Sausage Pizza Away)
What defines the OSI Model layers?
ISO 7498
Why do people refer to a Network stack?
The layers either operate from the top down, or the bottom up.
What is Layer 1 (of the OSI model) and what is it responsible for?
The Physical Layer. It transmits logical bits over physical current (1’s and 0’s). Even a wireless system is considered physical as far as the network stack is concerned.
* could be transmitted as electrical impulses across a copper wire, waves over an RF signal, or light over a fiber optic.
What are some devices that work at Layer 1 (Physical Layer)?
NICs (Network Interface Card), Repeaters and concentrators.
Which Layer in the OSI Model is called the MAC Layer?
Layer 2: Data-link.
What Layer does physical addressing occur?
Layer 2: Data Link
- MAC Layer
- Link Layer
- Deals with a unique address per device that is used for collision detection, error detection
- Deals with the reliable transfer of data.
In the Data-Link Layer (Layer 2), what does the link-layer (LLC) focus on?
governs sequence numbers and acknowledgements.
In the Data-Link Layer (Layer 2), what does the MAC deal with?
(Media Access Control) MAC governs data transfer and collision handling.
What are some devices that are associated with the Data-link Layer (Layer 2)?
ATM (asynchronous transfer mode), switches, bridges.
What Level does Logical Addressing occur?
Network Layer (Layer 3)
What level does Internet Protocol (IP) reside?
Network Layer (Layer 3)
Where does routing of packages occur? (From 1 point to another)
Network Layer (Layer 3)
At the Network Layer (Layer 3) what is a fragment of data called?
A packet
At the Data-link Layer (Layer 2) what is a fragment of data called?
A Frame
At the physical layer (Layer 1) what is a fragment of data called?
A bit
What are some devices you would find at the Network Layer (Layer 3)?
Bridges and routers
What are some protocols found on the Network Layer (Layer 3)?
IP, ICMP, IPSec
What layer deals with ensuring the delivery of information, and the control of the flow of information?
Transport Layer (Layer 4) . End to end connection reliability.
What protocols are associated with the Transport Layer (Layer 4)?
TCP (Transport Control Protocol), UDP.
Which layer is responsible for Inter-host or inter-application communication.
Session Layer (Layer 5)
What are some protocols associated with the Session Layer (Layer 5)?
RTCP, PPTP, RPC
What layer deals with compatibility between desperate systems, and data formatting. The layer that does the final steps to get the data in the proper format prior to delivering to the application.
Presentation Layer (Layer 6)
What layer does the Client software communicates with the network stack.
Application Layer (Layer 7)
What protocols are associated with the Application layer.
DNS, FTP, SSH, HTTP
