Understand Open Shortest Path First (ospf) Design Guide

General View of the Database

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RTC#show ip ospf database
OSPF Router with ID (203.0.113.67) (Process ID 10)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link count
203.0.113.67 203.0.113.67 48 0x80000008 0xB112 2
203.0.113.16 203.0.113.16 212 0x80000006 0x3F44 2
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
203.0.113.41 203.0.113.67 602 0x80000002 0x90AA
203.0.113.64 203.0.113.67 620 0x800000E9 0x3E3C
203.0.113.15192 203.0.113.67 638 0x800000E5 0xA54E
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
203.0.113.41 203.0.113.41 179 0x80000029 0x9ADA 3
203.0.113.67 203.0.113.67 675 0x800001E2 0xDD23 1
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
203.0.113.68 203.0.113.41 334 0x80000001 0xB6B5
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
203.0.113.150 203.0.113.67 792 0x80000002 0xAEBD
Summary ASB Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
203.0.113.16 203.0.113.67 579 0x80000001 0xF9AF
AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
0.0.0.0 203.0.113.16 1787 0x80000001 0x98CE 10
203.0.113.1288 203.0.113.16 5 0x80000002 0x93C4 0
This is a general look at the whole OSPF database. The database is listed in accord with the
areas. In this case, we look at the RTC database which is an ABR. Both area 1 and area 0's
databases are listed.
Area 1 is composed of router links and summary links. No network links exist because no DR
exists on any of the segments in area 1. No Summary ASBR links exist in area 1 because the only
ASBR happens to be in area 0.
External links do not belong to any particular area as they are flooded all over. Note that all the
links are the cumulative links collected from all routers in an area.
Concentrate on the database in area 0. The Link-ID indicated here is actually the Link-State ID.
This is a representation of the whole router, not a particular link. This seems ambiguous.
Remember that this high level Link-ID (actually Link-State ID) represents the whole router and not
just a link.

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