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cisco c certification.(LSU), which contains the link details; and the slave router adds this information to its local link state database and sends an LSACK to the master router again, acknowledging that the LSU has been received. o If the slave router's information is updated, it repeats the previous exchange and load states.4. Full adjacency (Full) state: After the master and slave routers are synchronized, they are in the full adjacency state. In summary, OSPFRouters share an LSA message to propagate available routes; basically, an LSA update message contains links, state, and other information. The link is the router interface on which the update is generated (a directly connected route); the state is a description of that interface, including the configured IP address and the relationship to neighboring routers. However, OSPF routers do not share this information with other OSPF routers, but only with DRs/BDRs on the network segment.OSPF routers share information about their directly connected routes with DR/BDRs, including the link state type, the ID of the annunciating router, the overhead of the annunciated link, and the sequence number of the link. This is different from the distance vectoring protocol. Distance vectoring protocols share the entire routing table with neighbors, except for routes learned from neighbors (horizontal splits), and except for directly connected routes covering neighbors. Be sure to familiarize yourself with the 4 steps a router takes to share a route with a DR/BDR.Upon entering the full adjacency state, OSPF uses incremental updates. This means that whenever a change occurs, the change is shared only with the DR, which in turn shares this information with the other routers in the segment. Figure 19.3 provides an example of this. In this example, network Z, which is connected to router C, goes down, and router C sends a multicast (with a destination address of multicast address 224.0.0.6) to the DR and BDR, telling them about the change. After the DR and BDR add this information to the link state database, the DR then informs the other routers in the segment about the change in network Z (using a multicast message that is sent to address 224.0.0.5, which represents all OSPF routers). The other routers receive such updates and then share them with the DRs of the other network segments to which they are connected.Note that the communication between OSPF routers is connection-oriented, although multicast is used. For example, if a router informs theChapter 19 OSPF Routing 503to the DR, the DR must acknowledge receipt of this new information to the source device. Similarly, the DR expects to receive an acknowledgement from all of these neighbors when it shares information with other routers in the network segment. Don't forget that when OSPF routers exchange updates with each other, an acknowledgement must be made, which ensures that the router received the update.In addition to incremental updates, the DR floods its database every 30 minutes to ensure that all routers in the segment have the latest link state information. The destination address used by the DR to do this is 224.0.0.5 (indicating all OSPF routers on the network segment) o