Yes, it is inevitable that I cover these.  I’m sure network types will be next.  Per my usual request, please correct my stupidity.

Type 1 - Router : This LSA type lists all the routers by RID as well as the networks to which that router connects.

Type 2 - Network : These LSAs represent broadcast network where more than one OSPF router may live.  Think Ethernet or multipoint segment.  These LSAs are flooded by the DR for that segment.

My prediction about covering network types was wrong.  I’m going to puke out some information about neighbor states for now.  As is always the case, corrections are welcome.

Down : No hellos have been received from this router.

Attempt : This state only applies to manually-configured neighbors on an NBMA network.  In this state, a router has sent unicast hellos to the neighbor but has not received any back from it.

I have had my nose deep in several books in preparation for my CCIE R&S written exam, so I haven’t been blogging much at all.  Now that I’ve made it to the more familiar topics, I’m hoping to get some notes posted.  I’ll start with OSPF message types.

As always, please feel free to correct me here.  I’m learning just like the rest of us.

Hello : These messages are used to establish neighbors and serve as keepalives among other things.