单项选择题 A new building has been added to the enterprise campus network， providing client access for desktop PCs， laptops， and IP phones for employees and guests. During verification， only a few laptops using  wireless are reported to have problems， while other desktops， IP phones， and most other wireless laptops are fully operational. Additional information received about the problem indicates that， while the problematic wireless laptops cannot reach internal corporate websites， they can reach the Internet.  Where should troubleshooting about this connectivity issue be focused？（）

单项选择题 You work as a network engineer for. You study the exhibit carefully. You have configured an interface to be an SVI for Layer 3 routing capabilities. Assuming that all VLANs have been correctly configured and based on the configuration example shown，  what can be determined？ （） Exhibit：

单项选择题 You have configured a Cisco Catalyst switch to perform Layer 3 routing via an SVI and have  assigned that interface to VLAN 20. To check the status of the SVI， you issue the show interfaces vlan 20 command at the CLI prompt. You see from the output display that the interface is in an "up/up" state.  What must be true in an SVI configuration to bring the VLAN and line protocol up？（）