Which statement describes the role of 802.1Q tagging in Ethernet networks?

Which statement describes the role of 802.1Q tagging in Ethernet networks?

• A. It inserts a VLAN tag into Ethernet frames to indicate VLAN membership.
• B. It encrypts wireless frames.
• C. It prevents collisions on the network.
• D. It assigns IP addresses to VLANs.

Answer: (C)

802.1Q tagging inserts a VLAN tag into Ethernet frames to indicate which VLAN the frame belongs to. This tag travels on trunk links that carry multiple VLANs, allowing switches to keep traffic separated and deliver frames only to ports within the correct VLAN. The tag carries the VLAN ID (and optional priority), and on access ports frames are typically untagged for a single VLAN while trunk ports carry tagged frames for several VLANs. This tagging is what enables VLAN segmentation and traffic isolation on shared Ethernet networks. Encryption of wireless frames, preventing collisions, or assigning IP addresses to VLANs are not functions of 802.1Q tagging. Encryption is a security feature for wireless frames, collision control comes from switching and network design (separate collision domains and full-duplex links), and IP addressing is handled by DHCP or manual configuration.

802.1Q tagging inserts a VLAN tag into Ethernet frames to indicate which VLAN the frame belongs to. This tag travels on trunk links that carry multiple VLANs, allowing switches to keep traffic separated and deliver frames only to ports within the correct VLAN. The tag carries the VLAN ID (and optional priority), and on access ports frames are typically untagged for a single VLAN while trunk ports carry tagged frames for several VLANs. This tagging is what enables VLAN segmentation and traffic isolation on shared Ethernet networks.

Encryption of wireless frames, preventing collisions, or assigning IP addresses to VLANs are not functions of 802.1Q tagging. Encryption is a security feature for wireless frames, collision control comes from switching and network design (separate collision domains and full-duplex links), and IP addressing is handled by DHCP or manual configuration.