Right condition for exchange the router by OSPF
The conditions for properly conveying route information are summarized in the table below.
|Establish neighbor||In Hello packets, following is the same,
|Exchange LSA||The topology type of Connetion Interface is multi-access,
and there is router(s) who has DR priority more than 1.
MTU of Connection Interface is the same.
|If Priority is 0, do not proceed from 2way.
If MTU is different, do not proceed from ExStart.
|Make Shortest Path Tree||The topology type must be the same.
(Multi-access to each other, or P2P each other)
|LSA exchange has done even if topology type is different,
but cannot make the tree because the link is inconsistent.