At least one device needs to be assigned to a Vlan 99 to
bring the protocol up. Assuming that the Status is UP and the protocol is DOWN
may mean that there are no ports assigned to Vlan 99 and thus no host assigned
to this Vlan.
The protocol of a management interface with VLAN 99 could be "down" because there are no ports assigned to it, meaning there are no hosts assigned to that interface. In this case, the status of the interface can be displayed as "up" regardless of the protocol.
