OSPF Redistribute Problem

RouterOS Forwarding Protocols
1

R2 <----> R1 <----> R3

[adm@R1] /routing ospf instance> pr
Flags: X - disabled, * - default 
 0  * name="default" router-id=172.16.25.78 distribute-default=never redistribute-connected=no 
      redistribute-static=no redistribute-rip=no redistribute-bgp=no redistribute-other-ospf=no 
      metric-default=1 metric-connected=20 metric-static=20 metric-rip=20 metric-bgp=20 
      metric-other-ospf=auto in-filter=ospf-in out-filter=ospf-out

I am struggling with the above now. On R1, although redistribute connected, static routes etc.. are all set to no, I still see the full routing table on R2 and R3
Why does R1 keep sending all the routes to other Routers (R2 and R3) when everything is set to NO ?

I dont need the full routing table on R2 and R3 since they only have a single uplink which is R1.

2

not sure why it would do that, but you could use the ospf-out route filter and create a default discard rule so it doesn’t advertise any routes.

3

Actually I dont want to play with the filters now since the OSPF instance parameters should take care of this.
Could anyone please try the simple scenario above and check whether if no matter how the instance is configured, it always distrubutes the routes or not ?

Version is 6.43.4 on CCR1072

4

It would have been great if you included /routing ospf export of R2 and R3 -

5 
[admins@R2] > rout ospf exp
/routing ospf instance
set [ find default=yes ] redistribute-connected=as-type-2 \
    redistribute-other-ospf=as-type-2 redistribute-static=as-type-2 router-id=\
    192.168.254.100
/routing ospf interface
add interface=ether1 network-type=broadcast
/routing ospf network
add area=backbone network=172.16.100.0/24

Same with R3. Simple setup 1 backbone area 3 routers.

6

Anyone ?

7

What is considered by “full routing table”? If you are talking about inter/intra area routes learned from other OSPF neighbors then those will always be installed in routing table for all routers in the same area.

8

there is only one backbone area. And R1 is the gateway of all other routers (r2 and r3).
I dont want R1 to distrubute any routes to R2 and R3 because in any case their gateway is R1.
How to stop R1 announcing all of its routes to other routers ?
I thought ospf-instance paramaters were supposed to do this.

9

What is the config on R1?

10 
[admin@R1] /routing ospf instance> pr
Flags: X - disabled, * - default 
 0  * name="default" router-id=172.16.2.2 distribute-default=never redistribute-connected=no redistribute-static=no redistribute-rip=no 
      redistribute-bgp=no redistribute-other-ospf=no metric-default=1 metric-connected=20 metric-static=20 metric-rip=20 metric-bgp=20 
      metric-other-ospf=auto in-filter=ospf-in out-filter=ospf-out




[admin@R1] /routing ospf network> pr
Flags: X - disabled, I - invalid 
 #   NETWORK            AREA                                                                                                                   
 0   172.16.100.0/24       backbone   
 ... etc




[admin@R2] /routing ospf instance> pr
Flags: X - disabled, * - default 
 0  * name="default" router-id=192.168.254.100 distribute-default=never 
      redistribute-connected=as-type-2 redistribute-static=as-type-2 
      redistribute-rip=no redistribute-bgp=no redistribute-other-ospf=as-type-2 
      metric-default=1 metric-connected=20 metric-static=20 metric-rip=20 
      metric-bgp=auto metric-other-ospf=auto in-filter=ospf-in 
      out-filter=ospf-out

[admins@R2] /routing ospf network> pr
Flags: X - disabled, I - invalid

NETWORK AREA

0 172.16.100.0/24 backbone

11

[admin@R1] /routing ospf network> pr
Flags: X - disabled, I - invalid

NETWORK AREA

0 172.16.100.0/24 backbone
… etc

Every added OSPF network that match IP address, will be advertised to neighbours. So if you do not want area routes received on other neighbors, then put those neighbors in stub area.

12

Thanks for your answer mrz.
Actually what I want to accomplish is not to distrubute the routes from R1 in the first place to minimize the multicast traffic on the wireless links.
I think what you are suggesting is filtering them on the R2 and R3 (on the receive side) so again R1 will distrubute them over the wireless link but will be neglected on R2 and R3.
Cant we do just the opposite and make R1 to stop announcing any routes at all ?

13

Taking a networks into stub area stops advertisements on both ends.
Is there a way to stop R1 announcing its area routes to R2 and R3 ?

14

Is there any particular requirement to use OSPF, instead of BGP? I find BGP is easier to configure, and the route filters work without troubles.

15

The router R1 will distribute all routes learned from routers of the same area by default. That is what OSPF is about. The redistribute-other-ospf=no is if you want to distribute or not routes of other areas. So you have to specify ospf-out filter to discart those routes in R1 in order to not distribute the routes or you have to use stub area.

16

Not correct, it is used to redistribute routes from one OSPF instance to another.

17

I think there shoud be a way to do it.
OSPF-OUT filter on R1 also doesnt stop R1 announcing its routes to R2 and R3 ?
Is this also an expected behavior ?

18

You can discard only external OSPF routes with routing filters. Everything you add to ospf networks will not be “external”.

19

My main concern was reducing multicast traffic on the links between R1 and R2,R3.
As far as I understand, it cant be done. Inner-area routes can not be filtered etc..

So what is the solution ?
Should I switch to BGP or is there any other way I can try to reduce the multicast traffic in the network using OSPF ?

20

I have the same problem. My ospf It is redistributing even if it is by default (do not redistribute in the ospf instance).

i did route filter but not work.

what is the solution?? there’s somewith with it?