单项选择题
A.VDSL
B.HDSL
C.ADSL
D.SDSL
多项选择题 Refer to the exhibit. Which three statements describe the steps that are required to configure an IPsec site-to-site VPN using a GRE tunnel？（）
多项选择题 WhatarethreeconfigurableparameterswheneditingsignaturesinSecurityDeviceManager（SDM）？（）
多项选择题 Whichtwostatementsaretrueaboutbroadbandcable（HFC）systems？（）