Name the two standards used for VLAN trunking.

Name the two standards used for VLAN trunking.

• A. 802.1Q
• B. ISL
• C. 802.3
• D. 802.1Q and ISL

Answer: (D)

VLAN trunking uses tagging protocols to carry traffic for multiple VLANs over a single physical link. The industry standard method is 802.1Q, defined by IEEE, which inserts a VLAN tag into Ethernet frames to identify their VLAN. Another method is ISL, Cisco’s proprietary trunking protocol that encapsulates frames to indicate VLAN membership. While 802.1Q is the widely adopted, vendor-neutral solution, ISL was used primarily on older Cisco networks. 802.3 is the basic Ethernet standard and does not specify trunk tagging. Therefore, the two standards used for VLAN trunking are 802.1Q and ISL.

VLAN trunking uses tagging protocols to carry traffic for multiple VLANs over a single physical link. The industry standard method is 802.1Q, defined by IEEE, which inserts a VLAN tag into Ethernet frames to identify their VLAN. Another method is ISL, Cisco’s proprietary trunking protocol that encapsulates frames to indicate VLAN membership. While 802.1Q is the widely adopted, vendor-neutral solution, ISL was used primarily on older Cisco networks. 802.3 is the basic Ethernet standard and does not specify trunk tagging. Therefore, the two standards used for VLAN trunking are 802.1Q and ISL.