多项选择题
A.PPP B.WAP C.DSL D.Ethernet E.L2TPv3
At which layer of the OSI model dose PPP perform?（）A.La...
单项选择题At which layer of the OSI model dose PPP perform?（）
A.Layer 3 B.Layer 4 C.Layer 2 D.Layer 5
Which protocol is an open standard protocol framework t...
单项选择题Which protocol is an open standard protocol framework that is commonly used in VPNs,to provid secure end-to-end communication?（）
A. L2TP B. IPsec C. PPTP D.RSA
which command is used to enable CHAP authentication whi...
单项选择题which command is used to enable CHAP authentication whit PAP as the fallback method on a serial interface?（）
A.(config-if)#authentication ppp chap fallback ppp B.(config-if)#authentication ppp chap pap C.(config-if)#ppp authentication chap pap D.(config-if)#ppp authentication chap fallback ppp
