1. [多选题]The Ezonexam network administrator issues the ping 192.168.2.5 command and successfully tests connectivity to a host that has been newly connected to the network. Which protocols were used during the test? (Choose two)
A. ARP
B. CDP
C. DHCP
D. DNS
E. ICMP
2. [单选题]帧中继环境下，为了区分虚电路，应该使用的地址是（）
A. IP地址
B. MAC地址
C. DLCI
D. IPX地址
