Which layer is this device working at?
The OSI model stacks seven layers, each using the one below it. Layer 7 sits at the top, closest to the user; layer 1 at the bottom, where actual signals travel.
The layer a device works at tells you exactly what it can and cannot see. That's not trivia — it's why one load balancer can route on a URL path and another one can't.
Place each device at the layer it operates on.
Components — tap one, then tap a slot on the diagram
?The layer a device works at decides what it can and cannot see — which is why one load balancer can route on a URL and another can't.
Boundaries, outermost first: Layer 7 · Application (HTTP, DNS): an empty slot for the reads URLs Layer 4 · Transport (TCP, UDP, ports): an empty slot for the sees ports Layer 3 · Network (IP, routing): an empty slot for the forwards packets Layer 2 · Data link (MAC, frames): an empty slot for the forwards frames This diagram draws no connections between its components.