Match each switchport configuration scenario on the left with its corresponding IEEE 802.1Q frame processing behavior or operational link state on the right.
- An untagged Ethernet frame arrives on a trunk port configured with 'switchport trunk native vlan 99'.The frame is mapped internally to VLAN 99 and forwarded without requiring an 802.1Q header.
- An 802.1Q tagged Ethernet frame with VLAN ID 30 arrives on a port configured with 'switchport trunk allowed vlan 10,20'.The ingress frame is dropped at the switchport interface boundary due to trunk pruning filter rules.
- A switchport configured with 'switchport mode dynamic auto' connects to an adjacent switchport configured with 'switchport mode dynamic desirable'.The port actively negotiates via Dynamic Trunking Protocol (DTP) and establishes an operational trunk link.
- An 802.1Q tagged frame with VLAN ID 50 arrives on a switchport configured with 'switchport mode access' and 'switchport access vlan 10'.The frame is discarded because an access port expects untagged frames and drops incoming 802.1Q tagged frames not matching its access membership.
Answer
Untagged ingress on native VLAN 99 maps internally to VLAN 99 without a tag; VLAN ID 30 on a trunk allowing only 10,20 is dropped due to pruning rules; dynamic auto connecting to dynamic desirable successfully negotiates an 802.1Q trunk link via DTP; tagged VLAN 50 traffic arriving on an access port for VLAN 10 is dropped.
The correct pairings accurately reflect standard IEEE 802.1Q frame processing rules and Cisco DTP negotiation matrix rules: native VLAN frames travel untagged; non-allowed VLAN traffic is dropped by trunk interface filtering; dynamic auto and dynamic desirable negotiate a functional trunk; and unexpected tagged traffic on access ports is dropped.
Step-by-Step Solution
Key Concept
VLAN Configuration and 802.1Q Trunking
Estimated Time:3m 0s