OSPF Route Summarization on ABR

0daymaster · Nov 27, 2019, 6:52 PM

Hi. I'm trying to summarize routes between two different OSPF areas. This should be fairly simple, right? Here is my config page for area 0.0.0.0 on my ABR. In area 0.0.0.10 I have a bunch of /24 subnets in the 172.16.0.0/16 and 10.6.0.0/16 prefixes. I want to advertise only 172.16.0.0/16 and 10.6.0.0/16 to my interior gateways in area 0.0.0.0. My current configuration seems to have no effect on route summarization (see screenshot of MikroTik router). What am I doing wrong here? Thanks.

pete35 · Feb 8, 2020, 9:47 PM

Same here, it looks like, it isnt implemented yet in FRR, see : https://github.com/FRRouting/frr/issues/5290

jimp · Feb 10, 2020, 6:36 PM

This worked the last time I tried it, but I don't have it enabled right now to check and none of the backups from my lab have it setup, just fragments.

Leave the substitute prefix blank. Putting the same value there is not valid and may be why it's not working (FRR may be rejecting the line)

Last time I did it, I believe what I did was:

Set the summaries on the local area (0.0.0.10 in your case)
Set this area as a stub
Set this area on the LAN interface(s)
Set the area to the backbone (0.0.0.0) on the interface facing the rest of the OSPF routers

pete35 · Feb 10, 2020, 8:32 PM

Do we really need a stub area for summarization?
According to that: https://study-ccna.com/ospf-summarization/
it isnt required.

jimp · Feb 10, 2020, 8:33 PM

No, that's just how I had mine setup in the lab when I know it was working. YMMV.

pete35 · Feb 11, 2020, 7:06 AM

I tried it again, but no success. OVPN routes and static routes are classified as external routes (AS External Link States) into the OSPF database,
so according to this: https://github.com/FRRouting/frr/issues/5290 they are not summarized. Only local LAN addresses have a chance to get summarized.