What are the characteristic of link state routing protocols? (Choose all that apply.)<br>A. The exchange of advertisement is triggered by a change in the network.<br>B. All routers exchange routing tables with each other iIn a multipoint network.<br>C. Packets are routed based upon the shortest path to the destination.<br>D. Paths are chosen depending on the cost efficiency factor.<br>E. Every router in an OSPF area is capable of representing the entire network topology.<br>F. Only the designated router in an OSPF area can represent the entire network topology.<br><br>答案:ACE<br><br>D错在哪里???<br>