OSI Layers Flashcards
What is the 7th layer of OSI?
Application Layer
What is the 6th layer of OSI?
Presentation Layer
What is the 5th layer of OSI?
Session Layer
What is the 4th layer of OSI?
Transport Layer
What is the 3rd layer of OSI?
Network Layer
What is the 2nd layer of OSI?
Data Link Layer
What is the 1st layer of OSI?
Physical Later
What is the application layer?
Where the user inputs data and data are output to the user.
What is an example of an application layer?
Web browsers - chrome, firefox, safari, skype, outlook
What is the presentation layer?
ensures that the information sent is reformatted back into the same format as the original and renders the underlying code into words, pictures, video, or audio. Encryption, decryption, and data
compression is also typically done at this layer.
What is an example of a presentation layer?
JPEG, GIF, MPEG, MIDI, TIFF
What is the session layer?
sets up, coordinates, and terminates communications, exchanges, and dialogues between the applications on each host. It deals with sessions and connection coordination.
What is an example of a session layer?
NetBIOS names, and Structured Query Language (SQL)
What is the transport layer?
deals with the coordination of the data transfer between end systems and hosts. It determines how much data is sent and at what rate.
What is an example of the transport layer?
Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)
What is the network layer?
Responsible for addressing packets and translating logical (Internet Protocol (IP)) addresses and names into physical (Media Access Control (MAC)) addresses. The network layer is concerned with the path data takes to reach the receiving device. Enables switching and routing technologies to create logical paths.
What is an example of the network layer?
Address Resolution Protocol (ARP), Routing Information Protocol (RIP), Internet Protocol Security (IPsec), and IPv4 & v6. Routers are network layer devices.
What is the data link layer?
responsible for the node-to-node delivery of the message. The main function of this layer is to make sure data transfer is error-free from one node to another, over the physical layer. When a packet arrives in a network, it is the responsibility of DLL to transmit it to the Host using its MAC address. It is divided into two sub-layers.
What is an example of a data link layer?
Institute of Electrical and Electronics Engineers (IEEE) 802.11 Wi-Fi, MAC, virtual local area network (VLAN), Fiber Distributed Data Interface (FDDI) and Neighbor Discover Protocol (NDP.) Switches are Layer 2 devices and operate at this layer.
What are the two sub-layers of the data link layer?
The MAC layer and the Logical Link Control (LLC) layer.
What is the MAC sublayer?
controls how a computer on the network gains access to the data and permission to transmit it
What does LLC stand for?
Logical Link Control
What is the Logical Link Control (LLC) sublayer?
controls frame synchronization, flow control and error checking
What is the physical layer?
represents the electrical and physical representation of the system. This can be conveyed either through electrical impulse, light, or radio signal through the network at the electrical and mechanical level.
What is an example of the physical layer?
physical topologies, digital subscriber line DSL, Ethernet physical layer, RJ45, and RS-232 connectors
Which layers are considered the “media” layers?
Network, Data Link, Physical
Which layers are considered the “host” layers?
Transport, Session, Presentation, Application
What does “PDU” stand for?
Protocol Data Unit
What is a PDU?
A unit of information that is sent by a protocol at a particular OSI layer
What is the PDU for the application layer (7)?
Data
What is the PDU for the presentation layer (6)?
Data
What is the PDU for the session layer (5)?
Data
What is the PDU for the transport layer (4)?
Segment, Datagram
What is the PDU for the network layer (3)?
Packet
What is the PDU for the data link layer (2)?
Frame
What is the PDU for the physical layer (1)?
Symbol
In what layer does the operating system lie?
The presentation layer