单项选择题 Which address is the IPV6 all-RIP-routers muticast group address that is used by RIPng as the destaion address?（）

单项选择题 Which statement is true, as relates to classful or classless routing?（）

单项选择题 Which device might be installed at a branch office to enable and manage an IPsec site-to-site VPN?（）