Which three mechanisms are used to secure management traffic from outside IPS sensors？（）

• A、 secure tunnels
• B、 a separate management VLAN
• C、 secure VLANs to isolate sensors
• D、 an out-of-band path around the firewall
• E、 asymmetric traffic flows to isolate sensors
• F、 private VLANs to put all sensors on isolated ports