OSI Model Flashcards
What Layer is Layer 1
Physical Layer 💪
Layer 1 (physical) spec
Specifies how to transmit and recieve RAW BIT STREAMS (could be things like voltage levels, timing, rates, distances, or anything really that could be used as a binary language)
T or F, are there individual addresses in Layer 1?
F - it’s only “broadcast” media
What is a layer 1 collision?
when two devices trasmit data on the same layer 1 link at the same time
What Layer is Layer 2?
Data Link! 🔗
What is a layer 2 frame
MAC address
a hardware address introduced by layer 2
Frame preamble
The first part of the frame which specifies the length
What is a switch
A Layer 2 device based on a hub. It can handle multiple host connections, and maintains a MAC address table, which maps addresses to devices.
This allows frames to be sent to the intended recipient
What happens when a switch gets a layer and the MAC address table is empty?
It will send it to all devices, but will get an aknwoldegement of which device the recipient is on – the table then gets updated so it can send directly in the future.
What layer is layer 3?
The Network Layer 🌐
Layer 2 sends frames; what does layer 3 send?
IP Packet
What is TTL and what does it do
TTL how many “hops” the packet can move through, after which is discarded.
Prevents infinite loops (or infinite hops)
In ipv4, what is an octet?
One section of an IP address (before one of the “.”)
When refering to the 1st, 2nd octet, etc, which directon do we start at, left or right?
left (ending at right); the first octet is the left-most octet.
