9tut ccna practice test

9tut ccna practice test.Complete exchange of LSAs with neighborsThe OSPF neighbor 2-way state means that the router can exchange its LSDB with its neighbor O In other words, it is ready to start the two-way exchange of LSDBs. Thus, once the two routers on the point-to-point link reach the 2-way state, they can immediately continue the process of database exchange.The database exchange process can be quite complex, containing several OSPF messages and several intermediate neighbor states. This chapter is more concerned with some of these messages, and the final state at the completion of the database exchange: the fUll state.After two routers decide to exchange databases, they do not simply send the contents of the entire database. First, they tell each other a list of LSAs in their respective databases, rather than all the details of the LSAs, just a list. (Think of these lists as checklists.) Each router can then check which LSAs it already has, and then request only those LSAs from the other router that it doesn't already know.For example, R1 might send a checklist to R2 with 10 LSAs (using an OSPF database description packet, i.e.1.2 Base Content 163DD package). R2 then checks its LSDB,and finds 6 of the 10 LSAs. So, R2 asks R1 (using a link state request packet) to send the other four LSAs O2.2 Base Content 164Thankfully, most OSPFv2 work does not require detailed knowledge of these specific protocol steps. However, there are some terms that are used more frequently and you should keep them in mind. In particular, the OSPF messages that actually send LSAs between neighbors are called Link-StateUpdate (LSU, Link-StateUpdate) packets. That is, the packet (LSU) contains the data structure known as an LSA. The Link-StateAnnouncement (LSA) is not a packet, but a data structure, which is inside the LSDB and describes the topology.Figure 8-3 uses an example that ties together these terms and processes. Continuing with the example in Figure 8-2, Figure 8-3 shows an example of the database exchange process between routers R1 and R2. The middle shows the protocol message, and the items on either side show the status of the neighbors at different points in the process. Pay particular attention to the following two items.