2a: OSI Model – A Practical Perspective Flashcards
(16 cards)
What is the purpose of networking?
To allow two hosts to share data with one another automatically.
What is the OSI Model?
A model with seven layers that explain how computers communicate over a network.
What does Layer 1 (Physical) do?
Transports bits (1s and 0s) between hosts using physical technologies.
What are examples of Layer 1 technologies?
Cables, Wi-Fi, Repeaters, Hubs.
What is a Repeater?
A device that extends a signal over longer distances (e.g., boosting Wi-Fi or cable signal).
What is the function of Layer 2 (Data Link)?
Handles hop-to-hop communication between two directly connected hosts.
What hardware works at Layer 2?
Network Interface Cards (NICs) and Switches.
What is a MAC address?
A unique hardware address assigned to every NIC.
What does a Switch do?
Forwards data to the specific port/device based on MAC address, enabling hop-to-hop communication.
What is the main job of Layer 3 (Network)?
Enables end-to-end communication between hosts using IP addresses.
What addressing scheme is used at Layer 3?
IP addressing — 32-bit addresses split into four octets (IPv4).
What devices operate at Layer 3?
Routers and any host with an IP address.
Why are both IP and MAC addresses needed?
IP addresses guide the data to the final destination across networks, MAC addresses guide the data on each local segment.
What is ARP (Address Resolution Protocol)?
A protocol used to map an IP address to a MAC address.
In the parcel analogy what does the IP address represent?
The delivery address of the parcel.
In the parcel analogy what does the MAC address represent?
The address of the current delivery truck or depot handling that leg of the journey.
