- A. Cisco Discovery Protocol traffic travels on the native VLAN by default.
- B. Traffic on the native VLAN is tagged with 1 by default.
- C. Control plane traffic is blocked on the native VLAN.
- D. The native VLAN is typically disabled for security reasons.
The native VLAN is the VLAN that is configured for packets that dont have a tag. The default native VLAN on all Cisco Switches is VLAN 1. It is always enabled by default. These settings can all be changed: That is: you can designate a different VLAN as the native VLAN, disable VLAN 1, etc. Knowing that, we can eliminate
D) as the correct answer because it is enabled by default. We can also eliminate B) because Native VLAN packets dont get tags by default (you can change this).
Finally, Control Plane traffic is never blocked on Native VLAN 1, and even if you change the Native VLAN, the control plane traffic still comes across VLAN 1.