📖 What is Trunk Port?
A switch port configured to carry traffic for multiple VLANs over a single link, typically used for connections between switches or between a switch and a router.
"By default, a trunk link allows all VLANs (1-4094). Use the 'switchport trunk allowed vlan' command to restrict unnecessary traffic across the trunk."
📚 Certification: Certified Network Associate (200-301)
🔑 What are the Key Concepts of Trunk Port?
- ▸ Multiplexing multiple VLANs over a single physical link
- ▸ 802.1Q frame tagging to identify VLAN membership
- ▸ Trunk allowed lists for traffic pruning and security
🎯 How does Trunk Port appear on the 200-301 Exam?
Configuring a link between two switches to ensure VLAN 10 and 20 traffic can traverse the uplink.
Troubleshooting a missing VLAN from a trunk's allowed list.
Implementing Router-on-a-Stick by configuring a switch's uplink to a router as a trunk.
❓ Frequently Asked Questions
How does a trunk port differentiate between traffic from different VLANs?
It uses tagging (typically 802.1Q) to insert a VLAN ID into the Ethernet frame header.
Can an end device like a PC be connected to a trunk port?
Normally no, as standard PC NICs don't understand 802.1Q tags, though some servers with virtualization do use trunking.