A.open报文B.update报文C.keepalive报文D.notification报文
单项选择题10.254.255.19 255.255.255.248的广播地址是()
A.10.254.255.23B.10.254.255.20C.10.254.255.1D.10.254.255.111
单项选择题IP 172.16.2.160,子网掩码为255.255.255.192,则该IP的网络地址是()
A.172.16.2.0B.172.16.2.128C.172.16.2.63D.172.16.2.252