As a network administrator, you issue the interface auto qos voip cisco-phone command on a port in an edge network. It is possible for a Cisco Catalyst switch to check if a Cisco IP Phone is directly attached to that port by:()
- A using DHCP snooping
- B snooping the incoming 802.1Q VLAN tag
- C using CDP
- D snooping the CoS marking on the incoming frame