Networking Concepts
At which OSI layer do routers primarily operate?+
- • Layer 2 — Data Link
- • Layer 4 — Transport
- ✓ Layer 3 — Network
- • Layer 1 — Physical
Routers forward packets between networks using logical (IP) addresses at Layer 3. Switches work mainly at Layer 2 using MAC addresses.
At which OSI layer do switches forward frames using MAC addresses?+
- • Layer 3 — Network
- • Layer 1 — Physical
- • Layer 5 — Session
- ✓ Layer 2 — Data Link
The Data Link layer handles frames and MAC addressing. Standard switches build MAC address tables to forward frames.
At which OSI layer do TCP and UDP operate?+
- ✓ Layer 4 — Transport
- • Layer 3 — Network
- • Layer 5 — Session
- • Layer 7 — Application
The Transport layer handles segmentation, port numbers and, for TCP, reliable ordered delivery.
Which OSI layer is responsible for encryption, compression and data formatting?+
- • Layer 5 — Session
- ✓ Layer 6 — Presentation
- • Layer 4 — Transport
- • Layer 2 — Data Link
The Presentation layer translates, encrypts and compresses data for the application layer.
Cables, connectors and voltages are defined at which OSI layer?+
- • Layer 2 — Data Link
- • Layer 3 — Network
- ✓ Layer 1 — Physical
- • Layer 4 — Transport
The Physical layer covers media, signaling, connectors and bit transmission.
Which port does HTTPS use by default?+
- • 80
- • 22
- • 3389
- ✓ 443
HTTPS uses TCP 443. Port 80 is plain HTTP, 22 is SSH and 3389 is RDP.
