单项选择题 A new asynchronous connection is being installed in your network. Which pair of WAN encapsulations types is suitable for asynchronous lines?（）

单项选择题 Which WAN technology was designed to give homes and small business high speed digital dial-up service over already existing communication infrastructure?（）

单项选择题 You are preparing to create a point to point WAN by connecting a Cisco router with a Juniper router by way of their serial links. Which one of the following commands would you use?（）