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cisco braindumps 2019.It is assumed that all routers in the segment are started at the same time. In this case, the OSPF routers will go through the following three states (switching process) to determine if they become neighbors.1. Down state: The router is not exchanging OSPF information with any other router. 2.2. Init state: The target router receives a Hello message from the new router and adds the new router to the neighbor list (assuming the previous aspects are the same). Note that communication is still one-way at this point.Two-way (Two.way) state: The new router receives an answer to its Hello packet from the target router and adds the target router to its neighbor database.Once the routers enter the bidirectional state, they are considered neighbors. Next, an election is held to select the Designated Router (DR) and Alternate Designated Router (BDR) for the network segment19.2.3 Designated Router and Alternate Designated RouterOSPF routers do not establish an adjacency relationship with any router; instead, OSPF makes a neighbor in each broadcast network segmentChapter 19 OSPF Routing 501using the client/server model. In each multi-access broadcast segment (such as Ethernet), there is a DR and a BDR, as well as other OSPF routers-these routers are called DROTHERs. for example, if there are 10 VLANs in a switched network, there will be 10 DRs and 10 BDROs A network segment without either of these The router's segment is the WAN point-to-point link.When the OSPF router boots up, it establishes adjacencies with the DRs and BDRs in each of its connected multiple access segments; if three segments are connected, three sets of adjacencies will be established. Routing information is exchanged between the DR/BDRs in the segment and the other OSPF routers. OSPF routers use IP multicast address 224.0.0.6 to communicate with DRs, while DRs and BDRs use IP multicast address 224.0.0.5 to communicate with other OSPF routers.