单项选择题
A.Router R2 will not form a neighbor relationship with R1.
B.Router R2 will obtain a full routing table, including a default route, from R1.
C.R2 will obtain OSPF updates from R1, but will not obtain a default route from R1.
D.R2 will not have a route for the directly connected serial network, but all other directly connected
单项选择题 The network administrator has discovered that the power supply has failed on a switch in the company LAN and that the switch has stopped functioning. It has been replaced with a Cisco Catalyst 2950 series switch.What must be done to ensure that this new switch becomes the root bridge on the network?（）
单项选择题 Which IPsec security protocol should be used when confidentiality is required？（）
多项选择题 Which two subnetworks would be included in the summarized address of 172.31.80.0 /20? （）