The 7 Layers of the OSI Model Flashcards
Why does networking exist in the first place?
To allow one device or person to speak with another device or person in another location.
Do the individual OSI layers care about the way other layers work?
No, only that the inputs and outputs are as expected
What does the physical layer concern itself with?
The ingestion of data.
How does the physical layer work?
Through a predefined electrical format such as voltage and frequency.
At what layer can one machine talk directly to another machine?
At the datalink layer.
What is the hardware address called that each machine or network interface have?
the MAC address
What does MAC stand for?
Media access control
What is the data encapsulation at the datalink layer called?
Frames
What types of information are contained in a frame
source and destination MAC address
At what layer is sequencing and flow control handled?
datalink
What is sequencing and flow control?
Controls transmission speeds and sequencing of data packets.
What layer handles error correction?
Datalink
What is error correction?
Datalink knows when data is damaged at the physical layer, and can resend the corrected packet(s).
What is the data encaspulation at the network layer?
Packets
What adressing is used at the network layer?
IP addresses
Does the networking layer handle error checking?
No.
What are some common protocols used at the networking layer?
IP
IPX
ICMP
What is the data encaspulation at the transport layer?
data segments
At what layer is host to host flow control added?
At the transport layer
True or false: Transport layer provides some error correction?
True, only in some cases.
What common protocols are used at the transport layer?
TCP
UDP
What transport layer protocol is designed for reliability over speed?
TCP
What transport layer is designed for speed over reliability?
UDP
When would TCP be used?
where accurate data is required, such as requesting a web page, or downloading a file.
When might UDP be used?
Where datapackets can be lost, such as Voice over Internet.
At what layer allows for ongoing connection of communication between to machines?
At the session layer.
At what layer are communication ports opened? (Think ports in security groups)
At the session layer.
What common protocols are used in the session layer?
TCP/IP AT (used by HTTP) UDP 53 (used by DNS)
At what layer to services understand the protocols being used?
At the application layer
What are the processes known as that allow one layer to submit information to another?
Data encapsulation
Data de-encapsulation
What protocol is used to discover the IP address associated to a MAC address?
ARP - Address Resolution Protocol
What is does a fully encapsulated packet look like?
data || TCP Header || IP || RMAC |
What is Layer 1?
Physical
What is layer 2?
Datalink
What is layer 3?
Network
What is layer 4?
Transport
What is layer 5?
Session
What is layer 6?
Presentation
What is layer 7?
Application
