单项选择题 Which protocol is used between the RAS and the authentication server in a narrowband network environment？（）

多项选择题 Which two forms of DSL connectivity provide the same bandwidth in both directions？（）

单项选择题 You would like toconfigure an ATM PVC with a virtual circuit identifier of 33 on virtual path 0.The PVC should use an unspecified bit rate and be encapsulated in the AAL5SNAP format. Which command accomplishes this goal?（）