In my previous post I covered Type 1 and Type 2 LSAs in relation to broadcast networks. In this post I’ll demonstrate how you can use these LSAs to map the topology an OSPF area.
Broadcast Networks – Type 1 + Type 2 LSAs = Area Diagram
First, let’s take a look at which LSAs exist in this area:
R1(config-if)#do sh ip ospf database
OSPF Router with ID (1.1.1.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 1850 0x8000000C 0x003FB9 1
2.2.2.2 2.2.2.2 370 0x8000000D 0x00278E 2
3.3.3.3 3.3.3.3 339 0x80000004 0x0001EA 1
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.1.2.1 1.1.1.1 823 0x80000003 0x0055C4
10.2.3.2 2.2.2.2 370 0x80000002 0x006C9F