A. DHCP snooping commands are not available until the feature is enabled with the feature dhcp- snooping command.
B. When you enable the DHCP snooping feature， the switch begins building and maintaining the DHCP snooping binding database.
C. The switch will not validate DHCP messages received or use the DHCP snooping binding database to validate subsequent requests from untrusted hosts until DHCP snooping is enabled globally and for each specific VLAN.
D. Globally disabling DHCP snooping removes all DHCP snooping configuration on the switch.
E. Globally disabling DHCP snooping does not remove any DHCP snooping configuration or the configuration of other features that are dependent upon the DHCP snooping feature.

A. The AED is responsible for sending all unicast traffic in a site， while either node in a site can transmit multicast and broadcast.
B. The AED is responsible for load balancing all traffic for all VLANs across the transport network.
C. The AED is responsible for handling all unicast， broadcast， and multicast traffic for a given VLAN within a site.
D. The AED is responsible for MAC address dispute contention for a given VLAN.