Which two VLAN trunking encapsulation methods exist, and which is non-proprietary?

Which two VLAN trunking encapsulation methods exist, and which is non-proprietary?

• A. IEEE 802.1Q and ISL; IEEE 802.1Q is non-proprietary.
• B. IEEE 802.1Q only; ISL is non-proprietary.
• C. ISL only; IEEE 802.1Q is non-proprietary.
• D. IEEE 802.1Q and ISL; ISL is non-proprietary.

Answer: (A)

VLAN trunking encapsulation methods determine how VLAN tags ride on Ethernet frames across a trunk. The two methods in use are IEEE 802.1Q and ISL (Inter-Switch Link). IEEE 802.1Q is an open standard defined by the IEEE, so it is non-proprietary and widely supported by equipment from many vendors. ISL, on the other hand, is Cisco-proprietary, tied to that vendor’s implementations rather than an open standard. So the two methods are 802.1Q and ISL, and the non-proprietary one is IEEE 802.1Q.

VLAN trunking encapsulation methods determine how VLAN tags ride on Ethernet frames across a trunk. The two methods in use are IEEE 802.1Q and ISL (Inter-Switch Link). IEEE 802.1Q is an open standard defined by the IEEE, so it is non-proprietary and widely supported by equipment from many vendors. ISL, on the other hand, is Cisco-proprietary, tied to that vendor’s implementations rather than an open standard. So the two methods are 802.1Q and ISL, and the non-proprietary one is IEEE 802.1Q.