Hello @gowdakssujan ,
the complex neighbor state of OSPF often creates confusion.
During the Exstart step A Master / Slave is elected based on OSPF RIouter ID RID.
During the loading phase the DBD database descriptor packets provide a list of LSA headers only
LSA header includes
LSA ID (it depends from type)
LSA sequence number : it ia a signed 32 bit integer first value id 0x80000001
Max Age (a bvalue less then 3600 seconds)
the slave takes notes of all missing or newer LSAa and sends out a LSRequest OSPF packet containing a list of LSAs it needs the master answers back with the whole content of each LSA .
The slave it irs tunr may need to provide at least the contect of its own Router LSA.
Only at this point the two routers reach the FULL state meaning their OSPF LS db for that area is in full sync.
see
https://datatracker.ietf.org/doc/html/rfc2328
To be noted the adjacency is built between two single devicess a pair.
in a Lan segment with multiple routers a new router builds the FULL adjacency with DR an BDR only and remains at state two way with other DR other nodes .
Hope to help
Giuseppe
