Which OSPF state involves the exchange of routing information?

The Exstart state is crucial in the Open Shortest Path First (OSPF) protocol as it is the phase where routers begin to negotiate the parameters for the exchange of link-state information. During this state, the routers establish a master-slave relationship, determining which router will control the sequence of database description packets being sent and which will respond. This is an essential step before the actual routing information can be shared between the routers.

In the context of OSPF, the Exstart state serves as the starting point for the process of synchronizing the link-state databases, which is necessary for creating an accurate and consistent view of the network topology. Only after the Exstart state is successfully completed can the routers enter the Loading state, where they will actually exchange the routing information. Thus, the Exstart state is the correct answer because it specifically pertains to the establishment of exchange parameters for routing information, setting the groundwork for later stages of communication.