I understand that when moving upwards from init through exchange to full states, ospf neighbors use received DBD packets to know which LSAs they need and make LSReqs as necessary.
- But, would 2 ospf neighbors ever move from 'Full to Exchange' or 'Full to Loading' states ?
- When a router sends Link State Refresh LSAs, does the neighbor state change from Full to any other state on it's table or on it's neighbor's table ?
- When a router sees that a previously received LSA has expired, does it make an LSReq for it ? (I think not, but the question is probably relevant here because, if an LSReq is sent, then maybe the state of the respective neighbor would be moved back to Loading/Exchange ?)