On the network shown in the figure, PC1 and PC4 belong to VLAN 10, and...

A, B, D, B, A, D

Interface-based VLAN assignment associates an incoming untagged Ethernet frame with the VLAN configured on its access interface.

On SW1, GE1/0/1 connects PC1 and therefore belongs to VLAN 10. GE1/0/2 connects PC2 and belongs to VLAN 20.

On SW2, GE1/0/1 connects PC3 and belongs to VLAN 20, while GE1/0/2 connects PC4 and belongs to VLAN 10.

The inter-switch interfaces GE1/0/3 must carry traffic belonging to both VLANs while preserving VLAN identification. Configuring these interfaces as hybrid ports with tagged forwarding for VLANs 10 and 20 achieves this requirement.

Using untagged forwarding for both VLANs on the inter-switch connection would remove their VLAN tags and prevent the receiving switch from reliably distinguishing the two VLANs.

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