Editing Open Shortest Path First (section)

=== {{anchor|Database description}} Database description (DBD) ===
{| class="wikitable  floatright mw-collapsible mw-collapsed" style="width: 400px;"
|+ OSPF v2 and v3 database description, field lengths in bytes
|-
! 16 or 24
! 2
! 1
! 1
! 1
! 4
! Variable
|-
| rowspan="2" colspan="1" | '''Header'''
|-
| Interface MTU
| Hello Interval
| Options
| Flags
| DD sequence number
| LSA Headers
|}

''Database description'' messages contain descriptions of the topology of the autonomous system or area. They convey the contents of the link-state database (LSDB) for the area from one router to another. Communicating a large LSDB may require several messages to be sent by having the sending device designated as a leader device and sending messages in sequence, with the follower (recipient of the LSDB information) responding with acknowledgments.