A trunk interface on a switch is used to carry traffic for multiple VLANs between switches or between a switch and another network device, like a router. Trunk interfaces use 802.1Q tagging to identify which VLAN the traffic belongs to.
Step-by-Step Breakdown:
Trunk Ports:
Trunk ports are typically used for inter-switch links or switch-to-router links where multiple VLANs need to be carried over the same physical connection.
VLAN traffic is tagged with a VLAN ID to ensure that it is properly identified as it crosses the trunk link.
802.1Q VLAN Tagging:
Trunk ports use 802.1Q to tag Ethernet frames with the VLAN ID. This ensures that frames are correctly forwarded to the appropriate VLANs on the other side of the trunk.
Juniper Reference:
Trunk Interface Configuration: In Juniper switches, trunk ports are configured to carry tagged traffic for multiple VLANs, which is essential for interconnecting multiple network segments.