多项选择题
A. Define the encapsulation type.
B. Define the standby router.
C. Define the standby IP address.
D. Enable the standby priority.
单项选择题 Refer to the exhibit. HSRP has been configured and Link A is the primary route to router R4. When Link A fails， router R2 （Link B） becomes the active router. Which router will assume the active role when Link A becomes operational again？" （）
单项选择题 Refer to the exhibit. The Gateway Load Balancing Protocol has been configured on routers R1 and R2， and hosts A and B have been configured as shown. Which statement can be derived from the exhibit？（）
单项选择题 Which command will need to be added to External_A to ensure that it will take over if serial 0/0 on External_B fails？（）