OSPF database

[gauravprakash]

HI,

I am confused with stub network concpets on OSPF database. Plz have a look on the Cisco doc .

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801ec9ed.shtml#exam

The networks of 5.0.0.0 /8 & 6.0.0.0/8 are shown as stub network. Network 6.0.0.0 /8 is a part of Backbone area and also 5.0.0.0 is in Area 1.

It reads: <<If the interfaces are on a common subnet, the routers install routes for any stub networks listed in their neighbor's router LSA. >>>

You can see the display of Show ip ospf data commands..these are shown as stub network.

PLz explain.

Thx,

Gaurav

[Richard Burts · Accepted solution]

Gaurav

I think that first we should be clear about what OSPF means by stub network. Note that the OSPF meaning of stub network is quite different from the EIGRP meaning of stub network. I quote this from the OSPF Design Guide from the Cisco web site:

Stub network links: This term has nothing to do with stub areas. A stub segment is a segment that has one router only attached to it. An Ethernet or Token Ring segment that has one attached router is considered a link to a stub network. A loopback interface is also considered a link to stub network with a 255.255.255.255 mask (Host route).

So the explanation is that since network 5.0.0.0 and 6.0.0.0 are point to point links and connect to only a single router that OSPF considers them as stub networks.

HTH

Rick