quote of the day, 2-way...

from:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f0e.shtml

2-Way

This state designates that bi-directional communication has been established between two routers. Bi-directional means that each router has seen the other's hello packet. This state is attained when the router receiving the hello packet sees its own Router ID within the received hello packet's neighbor field. At this state, a router decides whether to become adjacent with this neighbor. On broadcast media and non-broadcast multiaccess networks, a router becomes full only with the designated router (DR) and the backup designated router (BDR); it stays in the 2-way state with all other neighbors. On Point-to-point and Point-to-multipoint networks, a router becomes full with all connected routers.
At the end of this stage, the DR and BDR for broadcast and non-broadcast multiacess networks are elected. For more information on the DR election process, refer to DR Election.
Note: Receiving a Database Descriptor (DBD) packet from a neighbor in the init state will also a cause a transition to 2-way state.