Question-about the behavior of VLAN 1 BPDUs in a situation where the native VLAN configured as VLAN 99 and the native VLAN is tagged. (Choose two.)
A. Normal STP VLAN 1 BPDU travel across VLAN 99 untagged
B. PVST+ VLAN 1 BPDU travel across VLAN 99 tagged
C. Normal STP VLAN 1 BPDU travel across VLAN 1 untagged
D. PVST+ VLAN 99 BPDU travel across VLAN 99 tagged
AB?
https://community.cisco.com/t5/switching/how-bpdu-is-transmitted-with-native-vlan-for-pvst-and-mstp/td-p/1631995
If the native VLAN is different from VLAN1 then:
VLAN1 standard STP BPDU is sent untagged
VLAN1 PVST+ BPDU is sent tagged with VLAN1
Other VLAN’s PVST+ BPDUs are sent tagged accordingly (the one for the native VLAN will be untagged)
So, All vlan native such as Vlan99 is tagged, so all vlan is tagged.
The answer is B and D