OSPF : redistribute connected

[jeremygoutal]

Hello,

I have a question regarding the redistribute : connected command

I have a partial mesh topology with four routers R1,R2,R3,R4. the only missing link to have a fully meshed topology is from R2 to R4.

My question is : is there any guidelines regarding the "redistribute connected" command ?

I need to enter it on my R1 router as I have another network connected that is not participating in OSPF.

But on my other routers (R2-R3-R4), all my networks are already advertised in OSPF (except for my loopbacks) - I'm thinking the "redistribute connected" command is not necessary but would like to have confirmation.

Many thanks

Jeremy

[Rolf Fischer · Accepted solution]

Hi Jeremy,

when you use the redistribute connected command instead of enabling OSPF on the connected interfaces, the directly connected prefixes are injected as external routes into OSPF. This has impact on the flooding scope (domain-wide), filtering possibilities and increases the LSDB as well as the amount of OSPF traffic.

So nomally the much better approach is to enable OSPF on the interfaces and configure them as passive if needed.

HTH

Rolf

P.S.: The topology (full vs. partial mesh) is more a question of using the adequate network type.

[Rolf Fischer]

Here you can find a great posting by Peter Paluch with very detailed information about the disadvantages of redistributing connected prefixes: https://supportforums.cisco.com/message/3970307