Network Devices on One Revision Card

Lesson notes

Key points

• Hub – Layer 1: A hub repeats every bit out of all ports, one shared collision domain.
• Switch – Layer 2: A switch forwards frames using MAC addresses; each port is its own collision domain.
• Router – Layer 3: A router forwards packets between networks using IP addresses and blocks broadcasts.
• Firewall: A firewall filters traffic by rules on addresses, ports and protocols.
• Access point: A wireless access point bridges Wi-Fi clients onto the wired Ethernet network.
• Domains rule: Switches break collision domains; routers break broadcast domains. Say it before exams.

Takeaway: Switches split collision domains; routers split broadcast domains.