多项选择题 Which of the following are common VPN transports? (Select TWO)（）

单项选择题 A user reports sporadic connectivity with their wireless connection. A technician determines the wireless speed reported by the laptop to be 1Mbps. Which of the following is the MOST likely cause of this issue?（）

单项选择题 At which of the following layers does the ICMP protocol operate?（）