modify priority. OSPF neighbors can reach the 2-Way state without forming a full adjacency on a broadcast multiaccess segment when they are not required to become DR or BDR adjacencies. Changing OSPF priority is the mechanism that controls whether a router participates in the DR/BDR election. A priority of 0 prevents a router from becoming DR or BDR, so the neighbor relationship can be visible without the routers advancing to full adjacency with each other as DROTHER neighbors. Cisco CCNA 200-301 v1.1 IP Connectivity tests this because OSPF adjacency rules are not the same on all network types. Matching hello timers is required to become neighbors at all, but it does not explain the deliberate ' without forming an adjacency ' behavior. Process IDs are locally significant and do not have to match. The priority setting is the answer that changes the OSPF election role and therefore the adjacency outcome.