OSPF Tables

OSPF Tables:

In link state routing protocol there are different tables for storing different types of information regarding router and its networks. There are three tables in OSPF same like in EIGRP.
1.       OSPF Neighbor table
2.       OSPF Topology table
3.       OSPF Routing table

OSPF Neighbor table
Neighbor table contains the information of all connected OSPF routers.  In OSPF neighbor table OSPF have the information of neighbor status, IP address, timers, interfaces DR\BDR status, router-ID of connected OSPF router etc.
You can check the OSPF neighbor on a CISCO router by following command:

router#show ip ospf 1 neighbor

Router#show ip ospf 1 neighbor detail

Note: Where ‘1’ is OSPF process ID.

OSPF Topology table
In OSPF process each router have full road map of its entire area and this the one of difference between link state routing protocols and distance vector routing protocols that in Link state every router have complete understanding of their entire area. All such information in OSPF is stored in OSPF topology table. The difference between OSPF and EIGRP topology table is that EIGRP only know about it connected neighbor where as OSPF has full road map of entire area.
You can view the topology structure on a Cisco router by following command:

router#show ip OSPf 1 database

OSPF Routing table
Routing table has best routes for reaching different networks. OSPF use the SPF for calculation of best path in OSPF process.  You can check the routing on a CISCO router by following commands:

Router#show ip route
Router#show ip route ospf
Router#show ip route ospf 1

For More OSPF details you can visit OSPF design and concepts, link state routing protocols , distance vector routing protocols, OSPF virtual linksOSPF LSA Types.

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